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1995 Sedan De Ville (4.9 L)
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Discussion Starter #1
I thought I was going to own a troube free 95 SDV for a while after I rebuild the starter. It turned out that it lasted for only one day...

The starter is fine. But my transmission is acting a bit funny. It has about 101k miles on it.

Does a 4T60E have 1st to 4th and after in 4th gear does it lock-up at about 44 mph? I have to rev a bit more to shift from 1st to 2nd and 2nd to 3rd. It is shifting later than usual. Then, I feel that I don't get 4th. But I feel a shifting-like gentle shock at 44 mph as usual, which I assume it is locking-up. I feel that it goes like 1st -> 2nd, 2nd -> 3rd, 3rd to 44 mph and lock-up.

I didn't have a chance to go above 50 mph or so, so I am not very sure what I feel at about 44 mph is 3rd to 4th shifting or locking-up.

Anyway, nothing except this point seems to be going wrong. No codes. If some one said "this car has up to 3rd gear and lock-up", I would have believed because it appears to work just fine! But I know I should feel one more shock before going to above 44 mph... Any idea about what is going on? I am afraid this is an indication that the transmission is about to fail...

Thanks in advance.
 

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1995 FWB 128,*** miles
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It's hard to say at this point, but you can definitely test lock-up by maintaining constant 55 MPH with your right foot and slightly touching the brake pedal with your left foot (just enough to activate the brake switch). Watch RPM on the DIC (you might need to enter diagostics mode for digital reading). If RPM jump some 150-200 you are fine.

I assume your ATF is fine (level, color, smell).
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #3
Thanks HUF,

I confirmed that the transmission does lock-up, but without going into 4th gear.
When I checked, since it skipped 4th gear, rpm jumped by about 500 rpm or so without changing speed.

ATF seems to be fine to me. Maybe it looks a bit old (probably, never changed before), it is a bit brown red color and smells like ATF, no burning smell.

I studied a bit about a 4T60E:
it has 2 solenoids and uses both 2 while shifting from 1st to 3rd. So, if one of them were dead, I would have a trouble shifting not only 3rd to 4th, but also somewhere else. I will check signals to the transmission to see if they are OK. I even don't know if the trouble is internal or external to the transmission, since the transmission works fine except it doesn't go into 4th.

Any comments will be welcome!

Thanks.
 

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1995 FWB 128,*** miles
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100,

I just sent you info from FSM to test the solenoids (A,B and VCC). If your A solenoid failed you should have only D2 and D3. Are you sure you get D1. Does the car move if you start in D1?

The tranny is designed to lock up either in D3 or D4.
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #7
Thank you very much, HUF.

I really appreciate your help! I don't have a FSM yet. I thought if I needed it, I would bring it to a shop. But I am getting to the point that I feel comfortable doing something beyond what I can find at a library and on internet... One of my friends gave me a Chilton, but this is not very helpful. I will get a FSM soon (can't find it on eBay yet...).

According to what I learned, my 4T60E is slightly different from 4T60E on cars made before 1994 (wiring at the connector), but your copy explains what to do very well, so it is very useful. I may have to connect wires at different pins...

By the way, some questions:

(1) Does the transmission lock-up at 4th and 3rd? Doesn't it do so at 2nd? What I learned on the internet says 4T60E locks-up at even 2nd (but not at 1st). I just want to confirm it...

(2) When the transimisson does lock-up at 3rd, what is the gear-ratio? I suppose it would mean the converter physically locks-up, but the gear ratio should be equal to the value for the 3rd gear, not for 4th. Or when it does, does it lock-up at the final gear ratio for some reasons (mechanically, I don't think it would be the case, but I am just guessing...)? The reason I am asking this is because my car does go into the position where it gets final gear ratio when it locks-up. But I can't tell if this is because locking-up means fixing at the final gear ratio even it happens at 3rd or it is an indication that my 4th gear is alive.

(3) Can solenoids be replaced from the bottom of the transmission? I thought the side panel needs to come off, but I am not sure...

I made a little indicator to show what the PCM says to the transmission while driving. Unfortunately I couldn't put it between the transmission terminal and the harness. It was almost impossible to connect wires to the transmission terminal!!! Since I couldn't establish a good connection at the transmission terminal, I gave up to put the indicator and drive the car... I will have to get an extra connector that is on the harness side, so that I can connect my wires to the transmission with it. This would be much better... Maybe I will go to the junkyard and get it or hopefully I can find it on the web...

I didn't try to drive at 1st gear. I am almost sure I do still have 1st, but I will test and see if it it really true. My feeling is not accurate...

Again, thank you very much!
 

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1995 FWB 128,*** miles
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100,

You are welcome.

No lock up in 2nd gear in my tranny, only 3 and 4. Cannot say anything about the gear ratio. Cannot locate solenoids yet... The tranny section in the FSM can make anybody sick! LOL For "no 3-4 shift" the simplest thing to check out is the adjustment of the link (cable to PRND) switch right on the top of the tranny.

Unfortunately, it does not look like your solenoids are the problem. But I would still test them since it is the easiest thing to do. Anyone with tranny repair experience?
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #10
Update:

Today, I checked if the car moves when the shift lever is in 1st. It did. So I have the 1st gear (both solenoids) alive.

Also I put the lever in 3rd and observed how it locks-up. It did lock-up at about 44 mph and it locks-up at 3rd, I mean the gear ratio should be equal to the value of 3rd gear. I can tell that from rpm when it locks-up. Once the car locked-up at 3rd, I applied brake a bit and confirmed that it was not in 4th, but it really locked-up at 3rd.

Well, when the lever is in D, the car is in 3rd until it comes to 44 mph while I am driving it very gently. Then as soon as it hits 44 mph, it shifts into 4th and then locks-up almost simultaneously. I will check other stuff as HUF recommended, but I feel that it is a control problem, not an internal transmission problem.

My car has never acted like this. Why is it doing so???
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #12
OK, update...

Basic thing first! That is what I learned today.

I still notice a bit slow shifting from 3rd to 4th every now and then. Since this started happening, I also noticed slight reduction in mpg. So, I raised the car and checked how the wheels rotate. I worked on front this fall, so I checked the rear first. The rear left wheel was a bit heavy to rotate. When I removed the wheel and check the brake, the inner piston was stuck and the inner pad kept touching the rotor! That was bad. The pad was pretty worn, although the outer pad looks still fine. So, I broke the piston loose and... Yes, the car shifts fine now. It is still to early to say this was the cause, but I will keep my eyes on this.

Now I have to replace the pad and rotor, too. Previous owner said the brakes were replaced summer in 2003, oh well...
 

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1995 FWB 128,*** miles
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100 said:
OK, update...
Basic thing first! That is what I learned today.
I still notice a bit slow shifting from 3rd to 4th every now and then. Since this started happening, I also noticed slight reduction in mpg. So, I raised the car and checked how the wheels rotate. I worked on front this fall, so I checked the rear first. The rear left wheel was a bit heavy to rotate. When I removed the wheel and check the brake, the inner piston was stuck and the inner pad kept touching the rotor! That was bad. The pad was pretty worn, although the outer pad looks still fine. So, I broke the piston loose and... Yes, the car shifts fine now. It is still to early to say this was the cause, but I will keep my eyes on this. Pay attention the caliper bolts (pins) and their bushings.
Now I have to replace the pad and rotor, too. Previous owner said the brakes were replaced summer in 2003, oh well...
Rear brakes suck! They do only some 20% of braking, are hard to work on and are expensive. Pay attention to the caliper bolts (pins) and their bushings.
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #14
HUF,

HUF said:
Rear brakes suck! They do only some 20% of braking, are hard to work on and are expensive. Pay attention to the caliper bolts (pins) and their bushings.
Thanks for your advice!
Yeah, when I inspected, rubber boots were intact and the caliper moved smoothly. The piston was stuck, so at first I could not rotate the piston to back it up. I had to wiggle for a while to break it loose. Once it started moving, it felt fine to me. I didn't have time tonight, so I did it only on the left side. I will see the other side. It sucks that I didn't have new pads to install when everything was out!

I am glad I noticed this before it gets very bad.
 

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Discussion Starter #15
Today, I was playing a PCM while driving (I recently got FSMs, a lot to learn!). Then the car happened to start driving in the "better" way that I used to experience. I figured out that my thought of the transmission shifting late was wrong! My thought was that the transmission was not shifting from 3rd to 4th as it used to do. Well, it turned out that what I have been feeling was that my TCC started to engage late, not a shifting problem.

I could not find clear explanation on when the TCC engages during normal driving, but is it supposed to engage when the car is in 3rd in normal driving?
Or does it do only when the ATF is hot?

Thank you!
 

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Discussion Starter #17
Thank you for your reply!

HUF said:
Yes, TCC does not engage until ATF warms up.
Let me make sure... when you said "warm up", does it mean just "warm up" or the ATF gets abnormaly hot?

FSM gave me an impression that only when the ATF gets really hot (not within normal driving, like towing in hot weather or some sort...), the PCM uses a different shift/TCC control to reduce heat generation.

One more question. if the TCC engages when 3rd, does it cause any problems in long term? Like wearing TCC out quicker or so (this is what I am guessing)?
 

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1995 FWB 128,*** miles
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100 said:
Thank you for your reply!



Let me make sure... when you said "warm up", does it mean just "warm up" or the ATF gets abnormaly hot?

FSM gave me an impression that only when the ATF gets really hot (not within normal driving, like towing in hot weather or some sort...), the PCM uses a different shift/TCC control to reduce heat generation.

One more question. if the TCC engages when 3rd, does it cause any problems in long term? Like wearing TCC out quicker or so (this is what I am guessing)?
100,

I only remember that ATF should reach at least 160 F. Hopefully someone will chime in with more info.
 

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1995 Sedan De Ville (4.9 L)
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Discussion Starter #19
Some more additional info to share...

Today, my car locked up while in 3rd. I was monitoring the ATF temperature (PD19? I forgot...) and it was at around 30 C, way below 160 F (~70 C). I just don't know how the computer decide when to lock-up the converter! But after I turned the engine off, the car didn't lock-up in 3rd for the rest of the day, strange... My car runs and shifts fine, so I am not worried, but I am confused!
 
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