: Repairs to a 4T80E after 600+ hp

10-17-08, 07:30 AM
This trans worked great We did not expect to find any issues and I didn't plan for them.

This started out as Maintenance. The DHS is going to fall out of Certification Warranty. We have that 3500 Stall converter in the car. The stall Converter does NOT use a Viscous Clutch. Because of this the Turbine Shaft Seals can fail and the car will won't set a P0741 until the seals are missing.

We had planed to do a P0741 repair to this car. I know the seals are bad because the Side Cover was mismachined.

I raised the car up and found a slight leak out the left aft shaft. We know this to be a 3rd clutch housing issue and GM has update the the housing with a revised bushing to allow for better lubrication.

I had planned to do some work to the 2-3 shift accumulator because the trans had a long shift on N2O and after we stepped up to the 225whp Nitrous jet. If you think about WOT 2-3 shift with max HP (620) at 6800 rpm's this would be normal.

I figured a 3rd clutch housing and ordered the parts before I tore into it. I moved on to another third clutch housing job and waited for the part to come in.

We see the 3rd clutch piston burnt at time along with the clutches. I figured that this very minor leak would prove to be just a worn bushing. :hmm:
The clutches are burnt DUH it has slipped a few times. We just thought it was a long shift speed from the normal valving in the valve body.
I found the second clutch worn also, but this is normal to see and it was normal wear.

I will have some new pictures to post.
I will post all the modifications I do to the Upper Valve Body also.

10-18-08, 08:12 AM
What are you talking about?:confused:

10-18-08, 08:27 AM
An oil leak may be caused by bushing wear in the third clutch housing, causing excessive fluid build-up at axle seal.

Replace the third clutch housing with service P/N 8682114, which has revised bushing material to extend life and reduce left front axle seal leaks.

10-18-08, 08:36 AM
I did 2 of these in the car this week
I wasn't sure how it would go.
I pinched a ISS wire in the first one:rant2:
Lots of the other Techs came to see how it was going and if it was saving time.

10-18-08, 09:06 AM
First I drain the trans by removing the pan and the drain plug for the side cover. This is located on the left hand side and near the front of the car. It is an 11mm headed plug. I also pull the screens down to allow for more fluid drainage.
I reinstall the drain plug, screens, and the trans pan.

I pull down the front air deflector and start the coolant draining.

I then remove the air filter box and leave the PCM in it.

On the Seville I did - I removed the Surge Tank next

I removed the upper radiator hose

I removed the upper trans cooler line from the radiator and the lower one from the trans (just under the Thermostat Housing)

I removed the A.I.R. hose from the left bank valve and pushed the hose down towards the A.I.R. pump.

I disconnected the large C101 connector from near the master cylinder.

I pulled the wires looms over the engine to keep them out of the way.

I removed the shift cable and the bracket from the trans and pulled it back over the engine also.

I removed the master cylinder mounting nuts and unclipped the lines from the left frame rail. Now the master cylinder can be set over on the engine.

I removed the 2 throttle cables going to the Throttle Body and pulled them up by the windshield.

Then I remove the heater hoses from the engine. The one from the Connector at the back of the Cross-Over and the other from the Water Pump Cover. Then I tucked them beck by the Brake Booster.

Now I removed the pass through bolt for the engine mount on the Left Frame Rail.

Then I removed the Lower Radiator Hose.

I pull the vent hose off the trans and the dip stick/trans cap

I install a bungee cord to the lines going into the ABS unit and connected the other end so it just had enough pressure to keep it the unit suspended later.

10-18-08, 09:26 AM
Now I raised the car up and removed the cradle.

I started by removing the front cradle bolts an the front engine mount nut.

I removed the left front inner fender extension.

Then I remove the A.I.R. pump and removed the 3 blots holding the ABS unit to the cradle.

I removed the 1 bolt holding the brake lines in place on the front and pulled the 3 brake line retainers out of the cradle on the right side

I unclipped the A.I.R. plastic tube from the left side of the cradle

Then I unclipped the 2 clips from the left side of the cradle and the 2 from the front of the cradle

Then I remove the sway bar links

then I removed both ball joint nuts and popped the ball joints loose.

I removed both Tie Rod Ends, but you don't have to and they can be a pain to get the nut off.

I unbolted the P/S rack from the cradle and removed the 1 Bolt or Clip holding the P/S Pressure line to the cradle

Then I removed the bolts holding the rear engine mount to the cradle

I loosen the 4 nuts on the Catalytic Converter. I think it allows the engine to drop down better.

Now I remove the 4 rear cradle mounting bolts and lower the cradle down.

10-18-08, 10:05 AM
Next I remove the right axle from the trans

I remove the lower bracket from the trans bell housing to the oil pan because the GM trans jack adapter hits it.

I hook up the trans jack now

I remove the 2 brackets from the extension housing of the trans to the engine on the right side to the of the car.

I remove the Extension Housing next

Next I remove the Diff Carrier from the trans

Now I remove the clip from the oil cooler line on the trans near the extension housing. Some lines may be screwed in instead of the clip.

Now I remove the 2 nuts retaining the cooler line and get it out of the car.

After the I pooped the Left Axle out and I also remove it from the knuckle.

I push the output shaft into the trans and remove the clip on the right side.

Now I can remove the Shaft

Next I remove the LEFT Trans mount nut and lower the trans down part way

Remove the Steering Shaft Bolt from the Rack

I remove the trans mount from the frame rail and the mount bracket from the trans.

Now I slowly lower the trans side down until I can remove the Side Cover and set off to the side in a clean area

Next I remove the FILTER and unclip the wire harness

I lower the trans more to get to the Case Cover Bolts and bet clearance to remove it

Now this part I do a little different.
I remove all the bolts EXCEPT the red ones.
This allows for the Case Cover, Valve Body, and pump to be removed as one.
You will need to pry the Case Cover off the trans and two bearing will fall out at this time. Set the parts off to the side in a clean working area

This is were the bearing came from. Now remove the snap ring from the turbine shaft ( that is the one with the fluid running out of it ) and pry both of the sprockets off together. again set these off to the side in a clean area

Now remove the Driven Sprocket Support aka 2nd clutch housing and place it off to the side in a clean area.

Remove the rest of the 2nd gear clutch pack

Now I just loosen the 4th band servo cover, but you can remove it. This cover is on the back side of the trans near the P/S rack.

Now you can slide out the reverse clutch housing and the 3rd clutch housing and place them in you Clean Working Area

Now you can jack the trans back up if you want to take some pressure of the last mount.

10-18-08, 10:08 AM
On this car I had a lot of parts that show signs of slipping.
This is somewhat normal, but SI says to replace them so I am. They would probably go another 80K if we didn't use Nitrous. I have seen a lot worse on cars that other techs have reassembled using the old parts.

10-18-08, 03:05 PM
any room for additional clutch packs?

01-31-13, 07:54 PM

This article sounds like you were able to replace the 3rd clutch bushing and housing unit through the side cover. If so were you successful, how long did it take you, and around how much did it cost you to repair it. I ask because I have a 2004 Cadillac Deville DTS with a left axle seal leak and I know that it is a 3rd clutch bushing from the excessive play in the driver side axle. The car drives great and I have no DTC codes. I currently go through a quart tranny fluid every other day. I have replaced the axle seal twice with no luck. Any help would be greatly appreciated!

01-31-13, 10:02 PM
Holy 5 yr old thread resurrection batgirls!

01-31-13, 10:14 PM
I didn't realize this thread was 5 years old... ooops! I hope this AJ guy is still around so he can answer my question. To me this article seems to say that it is possible to remove the 3rd clutch bushing and housing through the side cover.

01-31-13, 10:15 PM
All the answers are in the last 4 posts................ and none of the principals have been around for years............... AJ may still check in once in a while.

........... and there are transmission threads in Cadillac Tech Tips.

01-31-13, 10:25 PM
Any tips or advice that you would give before I have someone fix the tranny. I would think accessing the 3rd clutch housing from the side cover would be far less intensive than completely dropping the tranny but I am not very mechanically inclined.

Manic Mechanic
01-31-13, 11:24 PM
Don't attempt what AJ did up there. I considered doing a similar repair with the tranny out and the costs of parts to replace the seals and other common wear parts on those covers and gears he's pulling and putting back was going to be well over $1,200. The complete trans from GM, all new or rebuilt by them is just over $2,000 my costs. Seriously? Why would I ever open that can of worms. I couldn't even get any of my transmission guys to open it up, they hate the 4t80E and only swap them. because they are so complex, so hard to pull and install, and often don't work right afterwards meaning they have to do it again and again until fixed, usually for warranty. So I could spend over half of what it would cost to replace it with a GM unit, trying with a chance of success (no guarantee that I could have even done it right without all the dealer tools and experience AJ has) to repair mine at 135K. No thanks I'll just get another new one and save my sanity. seriously I'm very mechanically inclined and the more I looked into performing major repairs on a 4T80E the more it seemed futile compared to replacing it with a reman. Not trying to be party pooper but you asked for advice and that's the best I can give you.

BTW, It would be cool for AJ to still be around but I can't even get him to answer PM's.


02-01-13, 12:35 PM
You can't get to the third clutch housing through the side cover.

The side cover is where the main filter, oil pump and tcc solenoid resides. You have to remove the channel plate that houses the seal. From there you can access the 3rd clutch housing.

I had spoken to AJ about this. It was doable in the car, but he stated other parts will be needed. Driving up the cost to repair the unit.

Otten33, take my word on this one.

Find another transmission that functions correctly.

02-01-13, 05:35 PM
My radiator ruptured and dumped coolant into trans fluid and trashed my trans internals. Fluid looked like mud. Is sitting in back of dads shop. Has lots of good hard parts in it. Too bad I hope to never need spare parts for my new trans. I hate to scrap it since I know that most of the parts are ok.

Manic Mechanic
02-01-13, 05:47 PM
I wish you were close, I need the front pump drive shaft. I think mine got a hair bent when the tranny was riding in the back of my pick-up and the converter started sliding off. I'm going into the Houston salvage yards yet again tommorrow morning in search of another.


02-02-13, 11:42 AM
I did

02-17-13, 08:56 PM
I have a 4T80E all apart that I would like to get rid of ASAP. It will be scrapped soon

02-24-13, 09:39 PM
I would prefer a good used trans over a rebuilt one any day, the 4T80E is a pretty common trans and easy to find for a reasonable price. Here is some information relating to Auroras, but it works for Cadillacs, too. I am putting a 3:71 Cadillac trans in my Aurora, along with a 275hp 4.6.

"All of this information is for 1995-1999 4T80-E Transmissions.

1. A 3.11 gear ratio transmission is ok as long as you can use your original torque converter and differential. When swapping the differential there is a spacer (washer) and thrust bearing on the end of the differential. The spacer is there for final assembly end play adjustment (5 different thickness ranges) and should stay with the transmission it came out of, not to be swapped out with the differential.
2. The wiring harness pinout is identical across these model years, but the internal harness of a '95 will not fit into later transmissions (into the case) due to the seal at the case where the harness comes out of the transmission. This is not an issue unless you are changing out the harness for some reason.
3. The shift cable bracket, and the shift lever (external bolted to transmission) need to stay with your Aurora, the Cadillac ones are different, and they are also different in Auroras (usage is from 95-96 same to 97-99 same). 1995 Park/Neutral safety switches are unique to an Aurora also and needs to stay with the vehicle (put it on your replacement transmission) if it's a 1995 car.
4. Replace the filter in the side cover. This should be done whenever you have the transmission or engine out, it doesn't make it much past 100k miles before starting to plug up with clutch material. If you get a hydraulic whine on a cold start in the winter you should change this filter immediately. I've seen more than 5 transmissions fail after seeing this warning sign."-aurorabrain from Aurora Club of North America.