'94 Olds Transmission - Car "won't" Reverse?

[Mezmeer]

Hello all. I am new to this forum and have never actually posted for help in a forum before. My issue is that I'm a computer guy - I fix computers, networks, check the security of networks, etc... I own a car though, and have a vested interest in learning to fix what I can.

 

So enough of the intro, here's my problem:

The car backs up, but any throttle applied will not effect the process. It will back up at an idle speed (sort of). If there is ANYTHING behind the tire (pinecone, foot, etc...) it will not have enough torque/power to push itself over it. This also means I cannot reverse if I am in a hole/puddle/bumpy area.

 

Background:

The check engine light comes on; I went to a garage and had our local mechanic/friend put it up on the "computer". It reported a problem with the quad driver module. I don't know what this is, and neither does any mechanic I've talked to in the area. I read that it controls all kinds of things though, but I don't quite understand it. My idea with my limited understanding is that if the QDM controls the converter clutch (lock-up transmission thing) and the clutch is burned out... that may be why the error is being reported. The blue plug which controls the TCC has been unplugged and the car no longer bucks at 30-45 miles an hour. The check engine light, however, still comes on. I have no idea if this is relevant - but it seems to be related to transmission in some way.

I do make sure the fluid is apt and I JUST changed the filter 2,000 miles ago. This reverse issue has been happening for the last 75,000 miles or so (before I got the car).

 

Thanks or reading, and any help or suggestions would REALLY be appreciated.

 

 

Edit: This is a

1994 Oldsmobile Cutlass Sierra S

2.2L - 4 banger - automatic transmission

[oldscsc]

If you can, get the exact codes (POxxx). That would help us out.

 

The torque converter clutch is never applied in first or reverse gears, so that's not what's causing your issue. Does the car just rev up when you give it gas in reverse?

 

When you're going down the road (slowly -- about 25 MPH would work) and put the gearshift in manual low (1), do you have engine braking?

[Mezmeer]

If you can, get the exact codes (POxxx). That would help us out.

 

The torque converter clutch is never applied in first or reverse gears, so that's not what's causing your issue. Does the car just rev up when you give it gas in reverse?

 

When you're going down the road (slowly -- about 25 MPH would work) and put the gearshift in manual low (1), do you have engine braking?

 

The check engine light should have no bearing on this really - as it only came on in the last 5,000 miles. If you're asking if when I manually downshift, does it pull the car down in speed, yes.

[oldscsc]

You have no issues whatsoever in any other gear, right?I'll see if I can find some hydraulic schematics to read pretty soon. Is this a 4T60E...anyone?

[RobertISaar]

alldata is saying a 94 2.2 cutlass ciera uses a 3T40(TH125C).

 

i have hydraulic diagrams for it... mentions in reverse that the direct clutch is applied and low/reverse clutch are applied.

 

checking 1st gear... low/reverse clutch applies, but instead of the direct clutch, the forward clutch is applied.

 

i imagine that's a clue.

[oldscsc]

Do you have an application chart Robert? (all planetary control devices and solenoids, preferably)

[RobertISaar]

i have hydraulic diagrams.

 

i'm not sure what all you're looking for, but i have a text based and graphical description of what goes on in specific gears and shifter positions.

[oldscsc]

I can try and interpret the hydraulic diagrams for the guy if you want to post em up. I guess the 3T40 is fully hydraulic so there wouldn't be solenoids...but an application chart just says which clutches, bands, or OWC's are applied in what gear. GM using non-electronic transmissions all the way into OBD II cars...

[RobertISaar]

more crazy GM fun: geo/chevrolet metros with the 1.0 used TBI up until they quit producing them(2000 was the final year). they used a cam sensor for OBD2 required misfire diagnostics, but still a single injector for all cylinders.

 

here's an album for the diagrams, since i don't feel like copy/pasting 20 IMGUR links...

 

http://imgur.com/a/mJhlw

[Mezmeer]

I can try and interpret the hydraulic diagrams for the guy if you want to post em up. I guess the 3T40 is fully hydraulic so there wouldn't be solenoids...but an application chart just says which clutches, bands, or OWC's are applied in what gear. GM using non-electronic transmissions all the way into OBD II cars...

 

I don't know much - as in all this talk of clutches and stuff is over my head... I do know that my car is not OBD II or OBD I... it's from the the transitionary period.

[oldscsc]

Ya know, sometimes GM is spot on the money...and others, they couldn't be more wrong W-bodies fall somewhere in between

 

That's a lot of stuff to look at. It's about my bedtime so I'll see if I can look at them tomorrow. But basically, all you have to do is isolate what reverse uses that nothing else uses. It's a lot easier than the diagrams make it look

[Schurkey]

The car backs up, but any throttle applied will not effect the process. It will back up at an idle speed (sort of). If there is ANYTHING behind the tire (pinecone, foot, etc...) it will not have enough torque/power to push itself over it. This also means I cannot reverse if I am in a hole/puddle/bumpy area.

Trans is fried. Internal problems. Could be simple, could be total overhaul.

 

Background:

The check engine light comes on; I went to a garage and had our local mechanic/friend put it up on the "computer". It reported a problem with the quad driver module. I don't know what this is, and neither does any mechanic I've talked to in the area. I read that it controls all kinds of things though, but I don't quite understand it.

It's a package of four output transistors. There are several quad-driver modules in the on-board computer. If the device they turn on/off is drawing too much amperage, the transistor pops due to current overload. GM was too stupid to install a current-limiting protection circuit.

 

Translation: Computer is popped, you need a rebuilt. You've also got a shorted wire or defective device that the computer turns on/off, that caused the quad-driver to fail. Examples could be: EGR solenoid, Idle Air Control motor, AIR pump solenoid, Torque Converter Clutch, or shift solenoid of an electronic transmission.

 

 

My idea with my limited understanding is that if the QDM controls the converter clutch (lock-up transmission thing) and the clutch is burned out... that may be why the error is being reported. The blue plug which controls the TCC has been unplugged and the car no longer bucks at 30-45 miles an hour. The check engine light, however, still comes on. I have no idea if this is relevant - but it seems to be related to transmission in some way.

I do make sure the fluid is apt and I JUST changed the filter 2,000 miles ago. This reverse issue has been happening for the last 75,000 miles or so (before I got the car).

 

Thanks or reading, and any help or suggestions would REALLY be appreciated.

 

 

Edit: This is a

1994 Oldsmobile Cutlass Sierra S

2.2L - 4 banger - automatic transmission

Cutlass Ciera isn't a W-body...is it?

 

alldata is saying a 94 2.2 cutlass ciera uses a 3T40(TH125C).

 

i have hydraulic diagrams for it... mentions in reverse that the direct clutch is applied and low/reverse clutch are applied.

 

checking 1st gear... low/reverse clutch applies, but instead of the direct clutch, the forward clutch is applied.

 

i imagine that's a clue.

Other car manufacturers have different names for the clutch packs or bands.

 

Direct clutch = High/Reverse clutch.

 

You must have at least two holding mechanisms to engage a gear. They can be a clutch, a band, or a one-way (roller or sprag) clutch. Sometimes three things hold a gear, but always at least two.

 

High/Reverse and Low/Reverse engaged at the same time = reverse gear

Low/Reverse and Forward engaged at the same time = Low gear

Intermediate and Forward engaged at the same time = Second gear

High/Reverse and Forward engaged at the same time = High gear

 

The issue here is that in low gear, there is usually a one-way clutch that ALSO engages--and the Low/Reverse is only engaged in MANUAL Low gear. Low/Reverse is therefore "optional" when going forward, but mandatory when backing up.

 

SO: If the Low/Reverse is weak, but the roller clutch engages along with the Forward, you'll have low gear but no engine braking in manual low. Reverse won't work properly because Low/Reverse is slipping.

 

First Guess: Low/Reverse is toast on this transmission. Could be hydraulic control; maybe more likely a popped seal.

 

If the trans is electronic, fixing the computer might fix the shifting. More likely, at least two separate problems; and the trans needs help anyway because the TCC is unplugged to "band-aid" a lockup shudder.

 

First thing I'd do is test the engine braking from about 25 mph. There should be MORE engine braking in manual low gear than in manual second, and essentially none in "Drive".

Edited June 1, 2012 by Schurkey

[Mezmeer]

I'm sorry, but I don't understand what's being said. I don't know what a w-body is. I just happened across this forum looking up information on QDM and you all seemed like very informed people on this technical stuff. I'm pretty sure the QDM code is talking about the TCC and is unrelated to my reverse issue. I understand I'm only band-aiding it, but I don't want to be stranded when the TCC gets so bad the car won't go into first (had a vehicle with that issue - my first car). So what all should I do to further troubleshoot and diagnose this reverse issue? I'm sure it's already been said but I don't understand much of what was said. Something about clutches engaging different things and somehow I can find out which is working and not. Thanks.

[Schurkey]

I'm sorry, but I don't understand what's being said. I don't know what a w-body is. I just happened across this forum looking up information on QDM and you all seemed like very informed people on this technical stuff. I'm pretty sure the QDM code is talking about the TCC and is unrelated to my reverse issue. I understand I'm only band-aiding it, but I don't want to be stranded when the TCC gets so bad the car won't go into first (had a vehicle with that issue - my first car). So what all should I do to further troubleshoot and diagnose this reverse issue? I'm sure it's already been said but I don't understand much of what was said. Something about clutches engaging different things and somehow I can find out which is working and not. Thanks.

Take the vehicle to a transmission specialty shop.

[Mezmeer]

I don't really want to do that - which is why I've consulted all of you very talented and smart people here on this board. =)

[AL]

First thing I'd do is test the engine braking from about 25 mph. There should be MORE engine braking in manual low gear than in manual second, and essentially none in "Drive".

Try this first, either way, your looking at having yours rebuilt or getting a known good trans installed

[Mezmeer]

Thanks, I guess that's about it. I guess I was hoping that it could be a bearing or something easy/inexpensive (no idea what I'm talking about). Thank you all though, and I guess if I decide to fix it, I'll report back the true solution.