: 4T80E 3.11 to 3.71 swap



AJxtcman
06-26-07, 06:55 PM
I have never done a swap from 3.11 to 3.71 gears. Bert want to wake up his DHS and make it a DTS. I think The VIN Y cams are equal if not better in 03. I did some checking and it looks like 2 part numbers is all I will need.
#24205233 is a Carrier, Front Diff. INCLS 101 to 109.
#08678825 is the sun gear
Just the two parts. I can not say my price, but it is worth it. He has the 17" rims already. The difference between the 3.11 with 16" and the 3.71 with 17" is about 3 to 4 MPH at 70.
I would need to set the ABS up for the 3.71 also.

24205233 List $659.60 Trademotion.com $379.73

8678825 List $144.56 Trademotion.com $83.22

Has anyone done this?
I can program it for 3.71

AJxtcman
06-26-07, 09:43 PM
Has anyone done this swap???????????????:hitstick: :hitstick: :dammit:



:wtf: :burn:

eldorado1
06-26-07, 09:55 PM
I have. Pretty simple. The only difficult part is getting the 10" snap ring out. That sucker is like 1/4" thick and difficult to get out of the groove.

thu
06-27-07, 12:54 AM
You might want to tell the computer about the change. I dunno what the side effects would be without it. I suppose you could always go to a dealer and get them to use the Tech Scan Tool on it.

Let us know how it goes.

AJxtcman
06-27-07, 05:46 AM
I have. Pretty simple. The only difficult part is getting the 10" snap ring out. That sucker is like 1/4" thick and difficult to get out of the groove.

The ring gear is the same part # so the snap ring won't need to come off.
correct?

AJxtcman
06-27-07, 05:48 AM
You might want to tell the computer about the change. I dunno what the side effects would be without it. I suppose you could always go to a dealer and get them to use the Tech Scan Tool on it.

Let us know how it goes.

I work at a Dealer and can tune the PCM.

jadcock
06-27-07, 07:11 AM
I think that would be the idea situation. The LD8 engine (good torque) with the 3.71:1 final drive. That's how the Pontiac Bonne GXP came I believe (with the 275 hp engine and 3.71 transaxle).

Maxb49
06-27-07, 07:18 AM
Is there a significant improvement in acceleration?

Maxb49
06-27-07, 07:20 AM
By the way, what does this cost?

AJxtcman
06-27-07, 07:35 AM
I think that would be the idea situation. The LD8 engine (good torque) with the 3.71:1 final drive. That's how the Pontiac Bonne GXP came I believe (with the 275 hp engine and 3.71 transaxle).

2005 Pontiac Bonneville
RPO....FV4...Ratio Transaxle Final Drive 3.71
.........LD8...Engine Gas, 8 Cyl, 4.6L, MFI, V6, HO
:thumbsup:

eldorado1
06-27-07, 08:08 AM
The ring gear is the same part # so the snap ring won't need to come off.
correct?

If you can get by without removing that snap ring, then do it. I don't know to be honest, but I don't know why I would go through all that work if they were the same part :bouncy:

But then again, maybe I just assumed they were different.

AJxtcman
06-27-07, 08:44 AM
If you can get by without removing that snap ring, then do it. I don't know to be honest, but I don't know why I would go through all that work if they were the same part :bouncy:

But then again, maybe I just assumed they were different.

Is the snap ring the one for the sun gear that holds it in place on theoutput shaft?
The ring gear has a large snap ring on it also, but I should not have to take it out.
Warranty time is 3.5 hour to change it.

eldorado1
06-27-07, 10:13 AM
No, the large one holding in the ring gear that eats small babies.

Maxb49
06-27-07, 10:59 AM
No, the large one holding in the ring gear that eats small babies.

EH! I asked how much it cost! Answer!


:) HAHA

AJxtcman
06-27-07, 11:20 AM
I have had so many of these tranys a part it is hard to remember. I am not talking about P0741, but the left aft shaft leak (3rd clutch housing failure) or 4th gear band burn up. I had a finnal drive out in the car once, so I know it can be done. I think 3.5 hrs is a lot of time for the way I did it. I have a special snap ring pliers for the output shaft snap ring.

AJxtcman
06-27-07, 06:52 PM
Bert AKA Highline Cady Ordered the parts today.
Now we can see what I have done to a DHS for less than $1000 Total. That would include the exhaust and intake also. Full cat back system.

Highline Cady
06-27-07, 11:01 PM
Hey just wanted to thank everyone for their input on this, especially AJ. I'm looking forward to the swap. I've driven many, many DTS's and STS's and personally think that the gears (3.71) make a big difference with how the car acts from a dead stop. I just want a little more go off the line and figure that this will help, it can't hurt. Except mileage, but I figure it'll only be 2-4 mpg. We'll see, I'll let you all know after I get it done and run it around for a little while. Parts are already ordered.

jadcock
06-28-07, 06:22 AM
I prefer the better torque of the LD8 engine (like what's in the SLS, DeVille, DHS, etc). But the 3.71 final drive vs. the 3.11 final drive should make a nice difference as well. Can't wait to hear how this turns out.

eldorado1
06-28-07, 12:52 PM
Honestly I couldn't really notice a difference in acceleration. Maybe 1/2 sec faster 0-60. Maybe. Maybe not. The highway RPMs were a lot higher. My gas mileage probably went down.

AJxtcman
06-28-07, 01:12 PM
Honestly I couldn't really notice a difference in acceleration. Maybe 1/2 sec faster 0-60. Maybe. Maybe not. The highway RPMs were a lot higher. My gas mileage probably went down.

We ran a 15.09 in the 1/4 on a hot humid day with the traction control on

Highline Cady
06-28-07, 03:24 PM
Edlo1,
A 1/2 secound 0-60 would make it worth my money. I hope your guesstimate is right. Thanks for the info.

jadcock
06-29-07, 09:38 AM
I suspect that it's not going to make THAT big of a difference. The SLS cars (3.11) run 0-60 in the 6.7-7.0 second range. The new Buick Lucerne (same powertrain) does it in the mid-to-high 6 second range. Virtually the same.

I loved the highway rpm of the 3.11 ratio. I could run 75 mph and still be under 2000 rpm. In the STS, I'm already at 2000 rpm by 60 mph.

Highline Cady
06-29-07, 11:35 AM
Jadcock,
I hear what you are saying about the change in RPM's (SLS vs STS) especially relating it to gas mileage, I'm assuming. I personally don't care about that. I figure it'll help a little with acceleration, and you just made me think, that'll let the pipes rattle a little more also (I have aftermarket exhaust), plus it should keep me right in the powerband also. Anyway, I'll post my impressions when it gets done. I appreciate everyones input on this so, Thanks again everyone.

AJxtcman
06-29-07, 12:48 PM
I suspect that it's not going to make THAT big of a difference. The SLS cars (3.11) run 0-60 in the 6.7-7.0 second range. The new Buick Lucerne (same powertrain) does it in the mid-to-high 6 second range. Virtually the same.

I loved the highway rpm of the 3.11 ratio. I could run 75 mph and still be under 2000 rpm. In the STS, I'm already at 2000 rpm by 60 mph.

You must have missed the 0 to 60 time with the 3.11 gears. 5.88 seconds
That is one slick program I have. VIN Y motor WOW:worship:

94greencaddysls
06-30-07, 04:04 AM
Could this swap be done with from 3.11 to 3.71 without a computer modification? I have a 94 so I OBDI, I'm just thinking an inline resistor of some sort could modulate the signal to the computer and fool it, though I really dont know how the signal works. I have my trans apart and the differential at hand, I'm just not sure how I could get the computer to co-op with me. Any ideas? or electronics wizards?

AJxtcman
07-04-07, 01:02 PM
2000 to 2005 Devilles and Sevilles.
Case Extension Replacement
Tools Required
J 8001 Dial Indicator Set

J 25025-7A Dial Indicator Mounting Post

J 28585 Snap Ring Remover

Removal Procedure

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
Support the vehicle with safety stands.
Remove the right drive axle. Refer to Wheel Drive Shaft Replacement .
Remove the wiring harness.
Remove the vehicle speed sensor. Refer to Vehicle Speed Sensor Replacement .
Remove the right transmission to engine brace. Refer to Transaxle Brace Replacement .
Remove the ground wire from the case.


FIG #1
Remove the following parts from the case extension:
Five 13 mm bolts (128, 129)

One 15 mm stud (127)

Remove the case extension (134) and the seal (126).
Remove the roller thrust bearing (132) and the selective washer (133).

FIG #2

Remove the 8 mm scavenge tube bolt.
Remove the scavenge tube by prying on the differential.
Remove the scavenge tube seal.


.
.
Final Drive Assembly Replacement
Removal Procedure

Remove the case extension. Refer to Case Extension Replacement .


FIG #3
Rotate the manual shaft (16) counterclockwise in order to place the transaxle in Park (P) and prevent the differential from rotating.

FIG #4

Remove the 4 bolts (119) from the differential housing to transaxle case.
Remove the differential carrier.

FIG #5

Push on the output shaft in order to expose the left side differential gear snap ring. Remove the left side differential gear to output shaft snap ring (56).
Remove the differential side gear (118) and thrust washer (117).

FIG #6

Remove the final drive carrier (100) and the thrust bearing.
Remove the final drive sun gear (121).

Installation Procedure

FIG #7



Install the sun gear (121) with the bushing and the seal side facing differential.
Install the final drive carrier (100). Turn the unit until it meshes with the sun gear and the internal gear teeth.

FIG #8

Install the left thrush washer (117).
Install the left differential side gear (118).
Install the snap ring (56).

FIG #9

Use the manual shaft to place the transaxle in park.
This will lock up the final drive unit. The actuator rod will move up.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Install the differential housing and the four bolts (119). Hand tighten, using a star pattern.
Tighten
Tighten the bolts to 76 Nm (56 lb ft).

Install the case extension. Refer to Case Extension Replacement .

jadcock
07-05-07, 11:18 AM
You must have missed the 0 to 60 time with the 3.11 gears. 5.88 seconds
That is one slick program I have. VIN Y motor WOW:worship:

That's a whole different discussion. I didn't say your computer tune didn't work. I said that there's not a big difference in performance between identical 3.11 and 3.71 cars, using the "same" (LD8) Northstar tune.

If your 3.11 car does 5.88 seconds NOW, and that drops to 5.22 seconds with the 3.71 gears, THEN I'll be impressed!

Highline Cady
07-05-07, 11:34 AM
Hell, I'd be happy with a 1/2 second drop in the 1/4. LOL

AJxtcman
07-07-07, 01:03 PM
:rice:
I got the gears out and on the bench. I started on Friday about 10 after 5. I had all my tool put away and was clocked out just before 6pm. I would say about 30 to 40 minutes on the way out.
I had to find the wheel lock key.
Wheel lock keys are a pain. Have you ever looked for one in a car that is not yours?:want:
My Service manager wanted to race me in Bert's DHS against his DTS. I really wanted no part of a hot trans to work on.
The way I look at it Monday morning it will be done.
I think of this as the ultimate N/A tune.
.
Hey Bert how much are you in to you Tune total?
Exhaust + Intake + PCM Tune + Gear set + Time slip = ??? $$
I mean the cost not the replacement cost.

:burn:

Highline Cady
07-09-07, 12:17 AM
:rice:
I got the gears out and on the bench. I started on Friday about 10 after 5. I had all my tool put away and was clocked out just before 6pm. I would say about 30 to 40 minutes on the way out.
I had to find the wheel lock key.
Wheel lock keys are a pain. Have you ever looked for one in a car that is not yours?:want:
My Service manager wanted to race me in Bert's DHS against his DTS. I really wanted no part of a hot trans to work on.
The way I look at it Monday morning it will be done.
I think of this as the ultimate N/A tune.
.
Hey Bert how much are you in to you Tune total?
Exhaust + Intake + PCM Tune + Gear set + Time slip = ??? $$
I mean the cost not the replacement cost.

:burn:

Sorry AJ, didn't notice that anyone had posted on this thread for a while. To answer your question, I'm not really sure AJ, not as bad as some might think, the exhaust was free, well it was a swap with my factory pipes so all I payed for was the gasket, the intake was a birthday present, tune :worship: and gears well you know, find out on the gears this week, be gentle, LOL and the time slip, I think it's $37 on the weekend and $30 during the weekdays. Find out for sure this weekend have to get the Cady down there for giggles.:thumbsup:

AJxtcman
07-09-07, 11:32 AM
Gears

AJxtcman
07-09-07, 11:34 AM
85° outside and I left the AIR ON.
I can't believe I left the AIR ON
14.61 @ 103.5

Highline Cady
07-10-07, 01:58 AM
AJ, I'm loving the new gears. Great work!!! Thanks again.

Highline Cady
07-10-07, 02:00 AM
Oh ya and thanx for posting the pictures.

jadcock
07-10-07, 07:36 AM
Nice time. The car should have a WOT A/C cutout so it shouldn't matter if the A/C was on or not.

Highline, need more feedback! Better throttle response? Faster acceleration? Feels like another 100 horse? Details!

AJxtcman
07-10-07, 09:30 AM
Nice time. The car should have a WOT A/C cutout so it shouldn't matter if the A/C was on or not.

Highline, need more feedback! Better throttle response? Faster acceleration? Feels like another 100 horse? Details!

Close, but not quite. Yes the AC kick out at WOT, but how long does it need to see WOT before it releases the relay? How long does it take for the clutch to release?
1/2 second of lower power?
1/4 second before you get full power?
.
Jadcock Thank for your input from the beginning:thumbsup: I am glad you pointed out the GXP. That has real been a big help in shutting people up at the dealership. Thanks again.:worship:

AJxtcman
07-10-07, 09:32 AM
I was in to it all of 2 hours.

jadcock
07-10-07, 10:59 AM
Jadcock Thank for your input from the beginning:thumbsup: I am glad you pointed out the GXP. That has real been a big help in shutting people up at the dealership. Thanks again.:worship:

If I still had my '97 SLS, and you could tune out the difference in final drive ratio to make the PCM happy, I'd have you swap the gears. I agree that it's the best modification you can do to a LD8/3.11 car.

My brother owns my old '97 SLS now, maybe I'll mention this to him. :)

Highline Cady
07-11-07, 01:38 AM
Jadcock, sorry I've been out running around. To answer some of your questions, yes I think it has better throttle response, and yes the acceleration is better, no I don't think it added 100 horses. They are the same gears that you have in your STS. First the very little paperwork I can find on a factory stock DHS show 1/4 mile times at 16 flat. I know everybody has their opinions on G-Tech, but that G-tech on a hot humid day showed a 15.09 1/4 with the stock (3.11) gears and AJ's tune and exhaust and Volant intake. After the 3.71's were installed the very same G-tech showed a 14.61 on another hot humid day all other modifications were the same and the car had a full tank of gas.

So, no matter what your opinion of G-tech, there was a significant improvement. Now for all the years I'ved owned it with the 3.11's I personally feel a noticeable difference the last couple days with the 3.71's. AJ tuned it originally with the 3.11's and it would shift from second to third at 96 mph, with the 3.71's it shifts from second to third at about 83mph (I also have 17" STS wheels). So basically what I have noticed is quicker acceleration and when I'm driving around the car is reved up higher nearer to the torque band, which I like personally, but I'm sure will cost me some MPG's, but I personally don't care about gas mileage.

I personally think this was a huge change for my car. The gears and AJ's tune have really woken up my N*, bye far worth every penny, in my opinion, and truly that is all that matters to me. The exhaust, I think, did a little and the Volant only added noise (those things are shit for the Deville/DTS in my opinion, I laughed when I pulled it out of the box it was warped and there were huge gaps everywhere, so I modified it to fix all their F***UPS), it sounds great in combination with the exhaust don't get me wrong, but I think the intake may actually hurt performance slightly. Anyway, I was looking forward to getting the Cady down to the dragstrip this weekend but they aren't offering "fun racing" this weekend. They are on Wednesday nite, but I'm still not sure if I'll be able to get down there Wed. It sucks, this weekend would have worked out perfectly.

jadcock
07-11-07, 07:05 AM
Thanks for the review. It sounds like it was worth it.

I'm sure the G-tech isn't 100% empirically accurate, but I think it's a wonderful tuning tool, assuming you have your technique down and can launch the same every time. Even if it's not accurate to the 10th, as long as it's repeatable, it should be accurate to itself, and (as you say), a half second off the 1/4 mile is a half second off, whether it went from 16.0 to 15.5 or from 15.0 to 14.5.

Glad this worked out.

Highline Cady
07-12-07, 01:17 AM
Ya I'm loving it, I wish I'd have swaped these out years ago!

AJxtcman
10-03-07, 08:34 PM
:bump:
William I hope this will help.

Shaggy
10-04-07, 03:31 AM
My 02 STS is 3.71 final drive already, right?

AJxtcman
10-04-07, 06:43 AM
My 02 STS is 3.71 final drive already, right?

Correct.
You have a W rated tire STS also

Shaggy
10-07-07, 08:20 AM
Correct.
You have a W rated tire STS also

This is true. My shift points seem to be a lot higher than most of the other people are saying, too. Should I be expecting this with my programming?

MisterBlue
10-07-07, 08:39 AM
Is there a significant improvement in acceleration?

Yes, on the order of .3 to .5 tenths of a second in the 0-60 time. Passing times (50-70) wouldn't be as significantly affected, though.

AJxtcman
10-18-07, 07:27 PM
I did a 3.11 to 3.71 gear swap today in less than 1 hr. :eek:
Custom cradle hepls:cool2:

Now it is even faster:shhh:

BlackCaddy87
10-19-07, 02:52 AM
What was the total cost of this swap?

AJxtcman
10-19-07, 07:44 AM
What was the total cost of this swap?

:stirpot: $0.00

It was in my very own little turd. :thumbsup:

I am well aware that the 99 and prior needs the correct trans calibration to shift correctly. The 00+ is much easiers to swap that part of the program:eek: so now I have to work that out of my 99 program. It bounces of the revlimiter about 10 times before it will shift:(

:thumbsup:

BlackCaddy87
11-11-07, 07:00 PM
What all is needed to do this swap and how much money would it take?

AJxtcman
11-11-07, 08:13 PM
Could this swap be done with from 3.11 to 3.71 without a computer modification? I have a 94 so I OBDI, I'm just thinking an inline resistor of some sort could modulate the signal to the computer and fool it, though I really dont know how the signal works. I have my trans apart and the differential at hand, I'm just not sure how I could get the computer to co-op with me. Any ideas? or electronics wizards?

From what I have experienced you will need to change the PCM program on 93 to 99 cars. the 00 to 03 may not require it. I am not sure.


What all is needed to do this swap and how much money would it take?

You need 3 parts + fluid
Carrier #24205233 List $659.60 Trademotion.com $379.73
Sun gear #08678825 List $144.56 Trademotion.com $83.22
The Extension Case to Case Seal $??
Fluid about 6 quarts
96 to 99 PCM tune for this $200
$700 or so. New

AJxtcman
11-28-07, 06:42 PM
:bump:

dalamak
02-16-09, 10:33 AM
I was thinkgin about this swap myself, did you ever do it?

Highline Cady
02-17-09, 03:46 AM
Yep, been running around with the gears for well over a year now, threw in a stall while we were doing it. Love it!!! Should have been the first thing I did was get rid of those 3.11's. I personally think the 3.71's work real nice with the "base" cams. Why they didn't come from the factory that way, I'll never understand, they do stick the higher gear with the base N* finally but only in Pontiacs, go figure. God the Corsa's cackle on the highway from the extra rpms, I love that too!

dalamak
02-17-09, 04:06 PM
So it requires you to drop the Transmisson to do it?

dalamak
05-01-09, 11:52 AM
I Gonna be doing this swap, to wake up my SLS, MY question are the indicated tools Necessary, I don't see them refered to in the Procedure?

Also I have a 2001 STS Computer, since this swap is being done with a 2001 SLS, Is it better to swap the computers to have the Shift points match up but throw the fuel/timing tabels off or is it better to leave the SLS PCM and have the shift points off?






2000 to 2005 Devilles and Sevilles.
Case Extension Replacement
Tools Required
J 8001 Dial Indicator Set

J 25025-7A Dial Indicator Mounting Post

J 28585 Snap Ring Remover

Removal Procedure

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
Support the vehicle with safety stands.
Remove the right drive axle. Refer to Wheel Drive Shaft Replacement .
Remove the wiring harness.
Remove the vehicle speed sensor. Refer to Vehicle Speed Sensor Replacement .
Remove the right transmission to engine brace. Refer to Transaxle Brace Replacement .
Remove the ground wire from the case.


FIG #1
Remove the following parts from the case extension:
Five 13 mm bolts (128, 129)

One 15 mm stud (127)

Remove the case extension (134) and the seal (126).
Remove the roller thrust bearing (132) and the selective washer (133).

FIG #2

Remove the 8 mm scavenge tube bolt.
Remove the scavenge tube by prying on the differential.
Remove the scavenge tube seal.


.
.
Final Drive Assembly Replacement
Removal Procedure

Remove the case extension. Refer to Case Extension Replacement .


FIG #3
Rotate the manual shaft (16) counterclockwise in order to place the transaxle in Park (P) and prevent the differential from rotating.

FIG #4

Remove the 4 bolts (119) from the differential housing to transaxle case.
Remove the differential carrier.

FIG #5

Push on the output shaft in order to expose the left side differential gear snap ring. Remove the left side differential gear to output shaft snap ring (56).
Remove the differential side gear (118) and thrust washer (117).

FIG #6

Remove the final drive carrier (100) and the thrust bearing.
Remove the final drive sun gear (121).

Installation Procedure

FIG #7



Install the sun gear (121) with the bushing and the seal side facing differential.
Install the final drive carrier (100). Turn the unit until it meshes with the sun gear and the internal gear teeth.

FIG #8

Install the left thrush washer (117).
Install the left differential side gear (118).
Install the snap ring (56).

FIG #9

Use the manual shaft to place the transaxle in park.
This will lock up the final drive unit. The actuator rod will move up.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Install the differential housing and the four bolts (119). Hand tighten, using a star pattern.
Tighten
Tighten the bolts to 76 Nm (56 lb ft).

Install the case extension. Refer to Case Extension Replacement .

K STS
05-19-09, 09:09 PM
Highline and AJ,

I was thinking about doing a swap from the base 2.73 gears in my 1SE V8 STS to the 1SG 3.42 gears. Do you think either of you would have any information this install, IE whats required, etc?

K STS
05-23-09, 06:26 PM
bump...

Submariner409
05-23-09, 10:07 PM
The title of this thread is "4T80E 3.11 to 3.71 swap".

You are fooling with an entirely different critter. Based on your Profile post count you can PM either member and/or maybe start a new thread here or up in RWD STS.

K STS
05-24-09, 02:46 AM
I tried to start a new thread, it got moved to the 05-2010 STS section?

AJxtcman
05-24-09, 05:31 PM
let me do some research and let you know what it will take.

dalamak
05-26-09, 10:27 AM
You guys know if I can just manually shift the gears to get away without reprograming the shift points?

And wil this Swap throw off the speedo Calibration?

AJxtcman
05-26-09, 01:44 PM
You guys know if I can just manually shift the gears to get away without reprograming the shift points?

And wil this Swap throw off the speedo Calibration?

You can do some valve body work to control shifting better, bt the PCM does the other half. I would say it is maybe 70% & 30%.

dalamak
05-26-09, 01:58 PM
You can do some valve body work to control shifting better, bt the PCM does the other half. I would say it is maybe 70% & 30%.

So does this swap Idealing require Valve body modifaction and PCM reprogramming?



and the remark- "I would say it is maybe 70% & 30%" what do these % refer to?

Thanks Tim

AJxtcman
05-26-09, 08:08 PM
So does this swap Idealing require Valve body modifaction and PCM reprogramming?

Thanks Tim
NO on the valve body and Yes on the PCM.

AJxtcman
05-26-09, 08:17 PM
and the remark- "I would say it is maybe 70% & 30%" what do these % refer to?

Thanks Tim

If you were to disconnect the Trans connector and force the trans into first gear by powering up just the 1-2 shift solenoid the trans will still shift into 2nd via the valve body (fail safe). The PCM shift the trans by turning off the 1-2 shift solenoid.
Then if you were in 2nd and you wanted to down shift into 1st by a toggle switch on the 1-2 shift solenoid it still wouldn't down shift. Fail safe in the trans.
So you are out ice racing on a lake with a FWD Northstar Powered Caddy. You can't hold first gear unless you mod the valve body :sneaky:

dalamak
05-27-09, 09:49 AM
If you were to disconnect the Trans connector and force the trans into first gear by powering up just the 1-2 shift solenoid the trans will still shift into 2nd via the valve body (fail safe). The PCM shift the trans by turning off the 1-2 shift solenoid.
Then if you were in 2nd and you wanted to down shift into 1st by a toggle switch on the 1-2 shift solenoid it still wouldn't down shift. Fail safe in the trans.
So you are out ice racing on a lake with a FWD Northstar Powered Caddy. You can't hold first gear unless you mod the valve body :sneaky:

lol Well that's a very interesting scenario to put it as, thanks,

So under WOT accel, with an un modified Valve body, and not disconnecting the Trans connector, would the Higher Gear RAtio make the car shift gears to earlier or two late?

GizmoQ
05-28-09, 03:20 PM
Will you hurry up and move to Charlotte so you can start doing these mods on my ESC-V!

mazda1949
06-08-09, 05:35 AM
Hey guys , I've done this swap and the mechanical part is pretty simple. Of coarse I run a repair shop for a living and have been for about 40yrs or so.
I noticed a big difference in the bottom end acceleration so it was well worth the swap.
I have my northstar mounted in the rear of a Mazda pickup with a turbo. Plus I just put a 100 dry shot of of nitrous to get the turbo lag out of it. This thing is like a rocket!!!!!!!!!
To all you out there old AJxtcman is the (Guru) on the caddy northstar. He's like EF Hutton, when he speaks you better listen. AJ has helped me with the ECM and many other things since I started my little project.
I have a LS1 ECM running the engine and a stand alone transmission controller for the tranny.
I have a youtube video here if you'd like to see it in action.YouTube - Rear Engine Mazda pickup with a turbocharged Cadillac Northstar
Plus I have some pics on here of the swap.
http://www.cadillacforums.com/forums/cadillac-powertrain-control-module-pcm-tuning/121842-running-northstar-ls1-pcm-11.html

AJxtcman
05-13-13, 02:32 PM
Gears

I am getting old. Does anyone know how to ID these?

AJxtcman
05-17-13, 07:27 AM
90% sure the little sun gear is the 3.71

stoveguyy
05-23-13, 11:14 AM
I swapped trans and removed diff cover cuz donor had crack in bolt boss. Used my old case cover. Still not sure how diff is driven by fwd trans. Ya I understand how mechanical things work but have never torn apart a fwd transaxle