2G Automatic Transmission Rebuild

[Genhero]

I just bought an AWD 97 talon for very cheap but the automatic transmission had some issues. It engaged in D once or twice but would only do it the first time. Now it won't do it at all anymore. Reverse works every time.

I removed the transmission's pan and the fluid was very dark. Swapped the filter and replaced the fluid that came out. Cleaned the magnets, they weren't bad but the fluid was dark. I tried flushing the trans cooler but the pump wasn't pushing much fluid. It turns out it was way too low on fluid. I put it back together and put it in neutral and found out the transmission was 4 quarts low. I replaced the 4 quarts but didn't check how the flow to the cooler was afterwards.

If the PO ran it 4 quarts low, I'm guessing at least the front clutches are toast (which explains the black fluid). I can't seem to find a good used auto locally or that someone is willing to ship -- otherwise I'd buy it today. I'm going to disconnect the cooler lines again to see if the pump works in neutral now. If the pump works I was thinking of just doing a cheap rebuild and replacing the front clutches myself (only $100, worth a shot). There are no TCU codes. I haven't tried disconnecting the TCU to see if it moves in limp mode but I will just for kicks this weekend. It won't move with OD off either so it's not the end clutches (not saying they aren't junk too).

I don't know the condition of the torque converter or if I can even do a stall speed test if the forward gears aren't engaging but it probably took some abuse.

Would you guys pull the transmission and check the front clutches to see if they are toast and replace them/clean the valve body, etc or just call the transmission a throw-away (maybe keep it around for parts) and keeping looking for another one.

Any other ideas?

 

[Cougar232]

I know when the fluid gets really low it will default to reverse gear drive regardless of 1,2,D,OD. Sounds like the damage has been done if fluid is dark and smells burnt/toasty. I would either rebuild kit or find a decent used AWD Auto tranny on Classifieds . I found mine for a Spyder Turbo GST so you'll have better luck keep checking forums.

 

[Kapok6]

If its just a matter of replacing the clutches...its not that difficult.

 

[Genhero]

What do you mean by "it will default to reverse gear"? Will the TCU actually lockout forward gears for safety or just not enough fluid pressure to engage forward gears?

I was going to disconnect the battery tonight after work just to see if it would engage after it cooled off. I'm just worried that the extremely low fluid may have destroyed something besides the clutches (fluid pump or torque converter).[DOUBLEPOST=1412791333][/DOUBLEPOST]

If its just a matter of replacing the clutches...its not that difficult.

I'm not sure if it is just the clutches, the front and end clutches look very easy to change. I haven't checked the manual for the location of the rear clutches yet but hopefully it won't be too bad.

I'd prefer to find another awd transmission so I can rebuild this one on the side and spend more time on it but I'm kind of under the gun (it's a second car but it's going to be getting cold fast).

 

[Kapok6]

I'd prefer to find another awd transmission so I can rebuild this one on the side and spend more time on it but I'm kind of under the gun (it's a second car but it's going to be getting cold fast).

That would be the ideal solution IMHO. Find another known good trans, and rebuild this one while the other one is in the car and able to drive.

 

[Cougar232]

Yea not enough fluid pressure causes reverse in any gear happened to me a couple times when tranny was leaking out front pump seal. I know the AWD system is easy to disconnect(Did it as a newbie w/ no lift on cardboard) and you dont need a new transfer case or anything else.

 

[Genhero]

That would be the ideal solution IMHO. Find another known good trans, and rebuild this one while the other one is in the car and able to drive.

I'm still looking around but finding a 2g awd transmission around my area is like searching for a leprechaun. Bunch of fwd automatics or awd manuals. Most sites won't let me post WTB in classifieds yet so it may be a few weeks. =\

Yea not enough fluid pressure causes reverse in any gear happened to me a couple times when tranny was leaking out front pump seal. I know the AWD system is easy to disconnect(Did it as a newbie w/ no lift on cardboard) and you dont need a new transfer case or anything else.

I'll give it a try again tonight but I'm thinking there is no hope for those front clutches though. I'm not too worried about doing the actual swap -- I've been working on cars for about 10 years now. I'm just new to DSMs.

Thanks for the replies

 

[Genhero]

I disconnected the TCU and the transmission goes into drive (3rd gear limp mode) just fine.

---Summary---
No transmission codes.
With TCU:
Car won't go into D or any other forward gear
Reverse works fine

TCU Disconnected:
Reverse works fine
3rd gear limp mode works fine

The transmission does clunk pretty hard into R or D.

 

[BANGIN4]

I would rebuild...i just had the same issue with my trans did a full rebuild..seals clutches est. and that took care of the issue. I would take off the trans cooler and clean it out too.

 

[Beaubo]

Have you tried the 4G63 & EVO Buy and sell trader facebook page? Check it out you might find what you are looking for or find someone who can help you out.

 

[bmxfelon420]

I'd inspect the TCU for damage. Had a club member whose car wouldnt shift, he had some bad caps on the TCU. Replaced them and it's good as new.

Never heard of the car only going into reverse when low. Then again, the lowest my car has been on trans fluid was less than two quarts. The car just sorta lost forward bite going up steep inclines when it was that low, only for a second. It got a big air pocket in it from sitting. Luckily I purposely only drove it on very very short trips during that time to sort out the kinks.

 

[mustracetsi]

Please don't bash me. I go by old school tale. If trans was never service or maintain before 90k miles don't bother doing maintenance on it. Already has the wear and draining that dark fluid and cleaning the metals out you just removed what kept the car from slipping. If it was low I would just added quarts it was missing. Every car is different with trans services. Example lets say trans due every 45k and your car has 115k miles and service never done that's already twice the time it wasn't done. Same way with differentials. I go by this because I once did same thing as you but with different type of car and trans went to shit and couldn't fine the trans so I junked that ford probe. Do take my word just saying my opinion.

 

[bryanwheat]

Please don't bash me. I go by old school tale. If trans was never service or maintain before 90k miles don't bother doing maintenance on it. Already has the wear and draining that dark fluid and cleaning the metals out you just removed what kept the car from slipping. If it was low I would just added quarts it was missing. Every car is different with trans services. Example lets say trans due every 45k and your car has 115k miles and service never done that's already twice the time it wasn't done. Same way with differentials. I go by this because I once did same thing as you but with different type of car and trans went to sh** and couldn't fine the trans so I junked that ford probe. Do take my word just saying my opinion.

This is silly as hell and a myth. If there is no friction material left on the clutches than metal in the fluid won't keep the trans from slipping. There is either friction material left and it doesn't slip, or there is no friction material left and it slips, pretty simple. If you realize that your fluid is dark and burn't and the transmission is still working fine, than you WILL want to service is as soon as possible. The fluid as it breaks down looses it's ability to be pressurized. As this happens the trans will eventually stop working because the fluid can no longer properly be pressurized and the clutch packs and band's won't be able to be locked in properly. If you changed the fluid and the transmission failed than it already had internal issues that was going to fail soon anyway.

 

[mustracetsi]

Thank you for the info and more depth explanation on how the trans work. On you post you said if you change the fluid and fails it already has internal issues and going fail soon. But yet I seen cars well in 200k and never serviced the trans and trans still working and seen same car who change fluids in 100k but is pasted the recommend service mile and trans fail. Either way I learned something new.that's why I love this forum and all the members.

 

[Genhero]

It has all new fluid and a new filter. I checked the pressure control solenoid valve, solenoid a and b and TCC solenoid's ohms tonight and they are all within spec. They also all click when I put 12 volts to their terminal.

I don't think it's the front clutches. Based on the chart below "1" (low -- which doesn't engage) uses rear clutch and low-reverse brake. Reverse works so low-reverse brake is good and 3rd gear limp mode works so the rear clutch is driveable.

It goes into limp mode just fine when I either unplug the shift solenoids terminal or unplug the TCU but when everything is plugged in, it just revs and the solenoids won't engage 1st gear. I'm starting to think it's the TCU not controlling the solenoids correctly. There were no leaky caps when I pulled the TCU but I didn't look at the microprocessor to see if it was bulging (like I found in another thread). I guess it could also be a continuity issue in the harness but less likely.

I'm still looking for another transmission while I diagnose this one but I guess as long as I can move it around the driveway I'll continue to test it and work on other things on the car.

CLUTCH, BRAKE & BAND APPLICATION CHART
-------------------------------------------------------
Selector Lever Position Elements In Use
"D" (Drive)
1st Gear .................. Rear Clutch & One-Way Clutch
2nd Gear ................... Rear Clutch & Kickdown Band
3rd Gear ........ Front Clutch, Rear Clutch & End Clutch
4th Gear .................... End Clutch & Kickdown Band
"2" (Second)
1st Gear .................. Rear Clutch & One-Way Clutch
2nd Gear ................... Rear Clutch & Kickdown Band
"1" (Low)
1st Gear ............... Rear Clutch & Low-Reverse Brake
"R" (Reverse) .......... Front Clutch & Low-Reverse Brake
"N" Or "P"
(Neutral Or Park) .......... All Clutches, Brakes & Bands
Released Or Ineffective