: Torque Converter Whine



Mark D
12-10-11, 09:30 PM
I bought this really beat up '95 SLS, vin Y, for my wife to use while I have her '98 STS apart.
It doesn't have to go very far.
I knew about this whine before I bought it, and I'm just crossing my fingers that it'll keep going for a few weeks.
It's interesting, though, that the torque converter does not lock up, but it also sets no codes. I'm pretty sure it's torque converter, but it can easily be a pump, too.
That's all I know about it.
I appreciate any comments of other experiences of this sort ( I have been reading the other converter whine thread here)
The transmission is a recent install from a salvage yard, judging by all the yellow paint marker writing on it.
Thinking of driving it on a 400 mile round trip next week. I'm trying to get enough information to make a educated guess on how far I might get before I have to walk.

At 60 mph, how much slippage should I see judging by rpm change from throttle closed to throttle acceleration without dropping down a gear? I'm seeing roughly 1200 rpm. IIRC, the STS uses a different style converter, and my STS has had that changed anyway, but it only shows less than half that.

I could take my '95 STS, but it's salt season now.
Mark D.

Ranger
12-10-11, 11:49 PM
At 60 mph, how much slippage should I see judging by rpm change from throttle closed to throttle acceleration without dropping down a gear? I'm seeing roughly 1200 rpm.
I'm not sure what you mean by this Mark. The only time you can SEE the slippage is by holding the throttle steady above 41 MPH with your foot (no cruise) and then VERY lightly tap the brake to disengage the TCC solenoid. IF it was engaged, you should see a 200 - 300 RPM increase. THAT is the slippage being prevented by the TCC solenoid. No increase means the TCC is not engaged. IF you are asking what RPM you should see at any given speed, maybe this will help.

Mark D
12-12-11, 12:15 AM
I can understand why you didn't quite follow me. I didn't really state that properly.
I was just thinking that although the converter does NOT lock up, it seemed awfully loose to me as compared with my '95 STS. But they have different converters, so I can't really use that as any sort of comparison. Driving at 60 mph at a steady cruise, if I give it heavy throttle, but not enough for it to downshift, the tach jumps a good 1000 or more rpm. If I unlock the converter on my STS, it doesn't go half that. But, as I mentioned above, the two cars have two different converters. It would be comparing apples to oranges.
Forget all about that.
In fact, when I posted the OP, I sort of went off half cocked in the first place. I really didn't have my ducks in a row.
After driving it some today, and actually looking for specific things, I found that I can hear the whine in all gears, and in neutral.
This leads me to believe it's probably not a converter. I believe it's more likely a pump.
I'm not planning on doing any major repairs on this car. When it dies, it's dead.
I am, however, just trying to get some sort of input beyond what I already know.... that it can quit in fifty feet or fifty miles of five thousand miles or never.

This thing has, as you know, three pumps. I'm not at all familiar with the inner workings of a 4T80-E. I have worked on a few turbo 400's, but they're pretty simple. Other than that, automatic transmissions are not something I spend much time with.

So I'm looking for comments from anyone who has experienced a similar problem with their 4T80-E. What did it do? How long did you drive it like that before you repaired or replaced it? Was it a pump? If it died on you while you were driving, did it fail entirely, or did you manage to get home, even if it only had two gears left working?
And any other pertinent information. I don't really care that the converter doesn't lock up. That is a common problem, and a lot of people just ignore it. So will I. But that whine has me wondering about a bigger issue here. And no codes, with the converter not locking up. Weird?
I should add that when I first looked at the car, thinking to buy it, it had a converter code. Along with about 200 other codes. So many that I cleared them all, then went back a couple weeks later and checked it again to see what had reset during that time. Only two engine codes, an ISC code and something else I forget now. But no converter code, and still none.

About 7 or 8 years ago, my '95 STS gave me no warning at all, I was driving outbound on a 160 mile round trip. I stopped at a stop sign on a road in the middle of nowhere. When I started up, it shifted hard, and wouldn't go beyond third gear. Next time I stopped, it wouldn't go beyond 2nd gear. That's all I had 'till I got home. But it got me home.
I put in an A.C. Delco reman. But I don't think it was a pump failure in that case. Seems to me, it wouldn't do anything with a pump failure. Or is there a difference when there's three pumps in it?
Mark D.

Ranger
12-12-11, 12:50 AM
I was not aware that the two cars used different TC's. That 1000 RPM tach jump almost sounds like it is down shifting. If it's not, then I don't know what to say. I don't know much about transmissions. I DO believe you are correct about the whine though. I think that is pump related. Your '95 was probably simple shift solenoids. Cheap easy repair. Now all that said, have you have seen maeng9981's TC thread in this forum? That puts holes in the not the TC theory. :noidea:

maeng9981
12-12-11, 01:30 AM
I had whining noise, then I found P0741 which I cleared then it never came back. Performed trans fluid replacement with no improvement, except found a bunch of clutch material in the pan. I first lost 4th gear, then 1st, and then 3rd. I could still drive in second. Transmission fluid would puke out of overflow hose until it was dry inside.

I just got the used transmission installed on the engine, but I have yet to put it back in the car yet. I cut the old TC half, and found that the internal of the TC was all messed up. It looked like the quality of the TCC was terrible and it led to a total trans failure. The TCC produced bunch of clutch material and mixed the internal silicone fluid with trans fluid. You can find pictures in my thread.

If your TC isn't stock, there is a possibility that the quality of the unit is inferior to the factory one. 4T80E is reliable, but terrible quality TC like my old one could kill a perfectly fine transmission.

Mark D
12-12-11, 02:00 PM
Hi Ranger
Actually, the transmission failure in my STS (years ago) set a multitude of codes that indicated a lot more was wrong than shift solenoids. Using the service manual, I went through the diagnostic procedures and found that, without tearing it apart to know for certain, the most likely problem was loss of pressure because of failed seals, or O rings, that caused fluid to blow back into the pan instead of where it should have gone. I don’t recall exact specifics today.
With the torque converter problem already an issue, I made the decision to go with a total reman from a reliable rebuilder rather than patch up what I already had.
Not only are there different style converters from year to year and model to model, but GM changed converter styles for replacement units, too. I found that out when my "new" rebuild would still set a tq conv code after driving a few hundred feet down the highway. It turned out I needed a different EPROM to work with that converter. It works fine, now. Locks up nice and solid.
Did I mention that the transmission in the car was not original to the car? From the tag on it, I was able to determine that it had originally had the taller gear ratio ( I never remember numbers for long, but I think it’s like 3.11 or something) instead of the slightly deeper ratio used in the STS. Probably from an SLS. The gears, however, had been changed in it. And that, possibly, could have been what was causing the converter code to set, because it was the wrong converter for the PCM. At that time, a change of EPROM might have fixed that issue.
In the end, I think I made a much better car out of it by putting in that “new” transmission. It’s gone about 100K miles with hat “new” transmission now, with no torque converter issue.

I'm going to use the chart you provided, not on the SLS because that definitely doesn't lock up, but just to see how my STS matches up. Thanks for that. Is that in the service manual? I don’t recall seeing it.

Maeng,
How long did your transmission continue to work before the final meltdown began? Did yours whine in all gears and neutral?
I do know a guy who has ( had, he hit a deer pretty hard not long ago) a 2000 Deville that had the converter code from somewhere around 150,000 miles until the deer hit, at which time it had close to 250 K on it. The converter no longer locked up, he didn't care, and everything continued to work. But that was a factory original converter, not some whack job flushed-out claimed to be rebuilt converter from some hole in the wall transmission shop. Maybe I'm being too harsh, but your experience sort of leaves me cold.
That 4T80-E is a pretty complex transmission. My own opinion is that not just any shop is qualified to tackle it. Apparently not even the converter.
I might find out just how far this thing will go this coming weekend.
Mark D.

Ranger
12-12-11, 02:41 PM
You are correct on the 3:11 (SLS) final drive ratio Mark. The STS uses the 3:71.

No, that chart did not come out of the FSM. It was compiled by someone here with input from several members, but I have to apologize to the author for forgetting who to give credit to.

maeng9981
12-12-11, 04:42 PM
All this happened in 11 days. I found the whining noise on 9/21/2011 and the transmission finally quit on 10/1/2011. Yes it whined in every gear including parking and neutral. If it's just P0741 then it looks like you can just ignore. But with the whining noise it most likely means something else is not working right.

And I agree, the 4T80E is not like a normal automatic transmission. IMO It's not that complicated, but just like the Northstar, it needs to be handled by someone who knows what he's doing. (Apparently the "remanufactured" unit isn't really good also).

I hope nothing bad happens while you are on the road trip.

Mark D
12-13-11, 12:58 PM
Well, my AC Delco reman transmission has been working flawlessly since I installed it. That is, after I got the right EPROM in it.
When the converter locks, there is a barely discernable change in rpm when I give it heavy throttle, without allowing it to downshift. I was told by the parts guy at the GM dealership, that according to his book the converter is a new design to replace all the older converters in the earlier cars that had chronic torque converter problems. He just gave me the EPROM. Come to think of it, I think it's just a PROM.

The codes for my car would be different from yours, maeng, because your car is OBD-2, while mine is older, 1995, and is OBD-1. The typical slipping conver clutch code for the OBD-1 is P-039. There are other DTC's that can also disable the converter, but not necessarily converter related. Among them, from memory, is P086, which is undefined gear ratio. Several things can set this code, but it causes the ECM to disable the torque converter. One of these things would be running a transmission with the wrong gear ratio for the car.
If one were to use a transmission from a different model, like Seville SLS into an STS, that code would set if the gears were not changed. I understand the gears are easy to change, but I haven't done it myself. Not saying I couldn't do it, I haven't had to do it.

And there are a number of shift solenoid codes that will lock the car into second gear only. But in those cases it loses 1st gear too. In my case, when I had transmission trouble that fateful day, I still had first, it would not go beyond second. Second free-wheeled. I don't recall the codes that were set, but it was more than one.

I have access to a clean salavage yard 4T80-E that came from a '94 ETC. That should be about the same transmission as was used in the SLS, as it has the same 275 hp version Northstar engine. So I think it'll couple up to my '95 SLS if I were to wind up needing a transmission in it, and if I were to decide to repair it.
Mark D.