Auto Tranny Problem

[sunmicroman]

I have a 94 Metro auto transmission that has been having a strange tranny problem. When driving it home from work Friday it started to do what I thought was slipping. I would take off from a stop and it wouldn't shift gear but keep reving up until I almost took my foot off the gas and then it would shift. Then when it had to go into the next gear the same thing, I would accelerate the car and it wouldn't shift until I started to take my foot off the gas to keep the engine from overreving. Any ideas anyone? I vaguely remember another car I had a long time ago that did this and it was a vacuum hose to the tranny that was unconnected.

[DieInterim]

Originally Posted by sunmicroman

I have a 94 Metro auto transmission that has been having a strange tranny problem. When driving it home from work Friday it started to do what I thought was slipping. I would take off from a stop and it wouldn't shift gear but keep reving up until I almost took my foot off the gas and then it would shift. Then when it had to go into the next gear the same thing, I would accelerate the car and it wouldn't shift until I started to take my foot off the gas to keep the engine from overreving. Any ideas anyone? I vaguely remember another car I had a long time ago that did this and it was a vacuum hose to the tranny that was unconnected.

Hello,

These tranny's use a cable that controls shift pressure. If the cable has broken it will be stuck in "Full Throttle" setting; thus your high rpm shifting. However if your trans feels as if it is slipping... first check your fluid level as per the owners manual.

Blake

[hodunwun]

Originally Posted by DieInterim

Hello,

These tranny's use a cable that controls shift pressure. If the cable has broken it will be stuck in "Full Throttle" setting; thus your high rpm shifting. However if your trans feels as if it is slipping... first check your fluid level as per the owners manual.

Blake

DieInterim, I have a 96 LSI automatic that does not shift up or down.
Ruled out the ecm and the speed sensor on the tranny. The cable that controls shifting that you mention: would that be the shift linkage cable, the oil pressure cable or the interlock cable? Thanks for your attention.
doug

[Crvett69]

you have a dual cable coming from gas pedal, one goes to throttle and other goes to tranny. find where it is on top of transmission and have someone step on gas with car off a few times and see if cable on tranny is moving smoothly

[sunmicroman]

I think it may have been the cable to the tranny from the gas pedal. I adjusted it tighter and it seems to be OK now when I took it for a short drive around town. The real test will be on Monday when I commute to work. We'll see and keep posted here. Thanks for all of your help.

[DieInterim]

Originally Posted by sunmicroman

I think it may have been the cable to the tranny from the gas pedal. I adjusted it tighter and it seems to be OK now when I took it for a short drive around town. The real test will be on Monday when I commute to work. We'll see and keep posted here. Thanks for all of your help.

You know.. cables strech a little over time but they dont do it suddenly unless they are frayed and unraveling. I would treat that cable with suspicion.

Blake

[kvillard]

Hey folks,

I have an odd problem as well with my transmission. My car was stored for 9 months (driven a few times) while getting body work and chassis work done. Now that I'm driving it again, this happens:

When accelerating from a stop, the transmission in drive, the car takes of in drive, it does not shift down into 1st, then 2nd and then drive. It just slowly picks up speed in drive. If I manually shift into 1st and then 2nd and then drive, it works just fine. If I'm on the highway and apply the gas the car will not shift down (or into kickdown as we used to call it) -

Has anyone seen this - should I look at the cable mentioned above (I'm a car repair novice for sure)

Kent

[DieInterim]

Originally Posted by kvillard

Hey folks,

I have an odd problem as well with my transmission. My car was stored for 9 months (driven a few times) while getting body work and chassis work done. Now that I'm driving it again, this happens:

When accelerating from a stop, the transmission in drive, the car takes of in drive, it does not shift down into 1st, then 2nd and then drive. It just slowly picks up speed in drive. If I manually shift into 1st and then 2nd and then drive, it works just fine. If I'm on the highway and apply the gas the car will not shift down (or into kickdown as we used to call it) -

Has anyone seen this - should I look at the cable mentioned above (I'm a car repair novice for sure)

Kent

It would be wise to check the trans. fluid level as well as the cable. Low fluid level will slip clutches and engage improperly.

[hot_sd]

Originally Posted by kvillard

Hey folks,

I have an odd problem as well with my transmission. My car was stored for 9 months (driven a few times) while getting body work and chassis work done. Now that I'm driving it again, this happens:

When accelerating from a stop, the transmission in drive, the car takes of in drive, it does not shift down into 1st, then 2nd and then drive. It just slowly picks up speed in drive. If I manually shift into 1st and then 2nd and then drive, it works just fine. If I'm on the highway and apply the gas the car will not shift down (or into kickdown as we used to call it) -

Has anyone seen this - should I look at the cable mentioned above (I'm a car repair novice for sure)

Kent

Sounds like the shift signals from the ECU is not getting to the tranny. The PCM controls two shift solenoids (direct clutch and second brake) to generate first and second while in drive. If both solenoids are not energized the tranny will remain in third. I would check the circular connector with as I recall 2 wires and see if it is connected properly. Another possibility is one of the sensors like the VSS. If it is malfunctioning the ECU may not generate the shift signals correctly. Since you can maually shift into first and second it sounds to me like the main parts of the planetary gearset is fine.

[sunmicroman]

Well, the commute to work went great today and the car shifted fine through all gears at the right time. I think the accelerator to tranny cable adjustment did the trick. Thanks for everyone's help on here.

[docsplace]

I to have a trany shift problem, I have the 1994 that Shifts Fine when it is cold but as soon as it warms up it does not, I have to mannually shift it. Will not down shift or will not kick into passing gear it just like slips if you try to drop gears and goose it a little. Any Ideas on that one, Maybe the detent cable, Someone told me that there is a computer in the car under the dash that may have condensation and looses connection and may need cleaned.

Tom
Docsplace

[hot_sd]

Originally Posted by docsplace

I to have a trany shift problem, I have the 1994 that Shifts Fine when it is cold but as soon as it warms up it does not, I have to mannually shift it. Will not down shift or will not kick into passing gear it just like slips if you try to drop gears and goose it a little. Any Ideas on that one, Maybe the detent cable, Someone told me that there is a computer in the car under the dash that may have condensation and looses connection and may need cleaned.

Tom
Docsplace

Need a better description to suggest something with this problem. Does it remain stuck in third while in "D' or does it loose drive when you attempt a downshift. Is downshift the only problem - does it upshift OK.

Very easy to check whether the computer/sensors are to blame - when you have the problem disconnect the shift solenoid connector, put the car into 'D' and measure the voltage - you should see 12V on both lines (both solenoids should be energized).

I have to say that heat related problem usually tends to be due to things inside the tranny like dirty valves. You can try an transmission additive like lubegard and see if it helps - you may have some debris coating the shift valve(s) or the solenoid vent passages to the shift valves causing it to stick when hot. You can also check the cable from the gas pedal to the tranny's throttle valve - if it is out of alignment you could have problems with downshifts if the cable is becoming too slack due to heat (same thing as what the original poster had).

[docsplace]

Originally Posted by hot_sd

Need a better description to suggest something with this problem. Does it remain stuck in third while in "D' or does it loose drive when you attempt a downshift. Is downshift the only problem - does it upshift OK.

Very easy to check whether the computer/sensors are to blame - when you have the problem disconnect the shift solenoid connector, put the car into 'D' and measure the voltage - you should see 12V on both lines (both solenoids should be energized).

I have to say that heat related problem usually tends to be due to things inside the tranny like dirty valves. You can try an transmission additive like lubegard and see if it helps - you may have some debris coating the shift valve(s) or the solenoid vent passages to the shift valves causing it to stick when hot. You can also check the cable from the gas pedal to the tranny's throttle valve - if it is out of alignment you could have problems with downshifts if the cable is becoming too slack due to heat (same thing as what the original poster had).

It shifts fine downshift and upshifts when its cold, when it warms up it does not do either, If you start out in d when warm it goes but it is in d or 3, I have to down shift it. I can manually shift it but if i try to down shift while warm it just slips unless I am at a slower rpm or speed. I have put a new filter in it and lucas trany fix a week ago and drove it 350mi with no better results.

Thanks
Tom

[hot_sd]

Originally Posted by docsplace

It shifts fine downshift and upshifts when its cold, when it warms up it does not do either, If you start out in d when warm it goes but it is in d or 3, I have to down shift it. I can manually shift it but if i try to down shift while warm it just slips unless I am at a slower rpm or speed. I have put a new filter in it and lucas trany fix a week ago and drove it 350mi with no better results.

Thanks
Tom

Still not too clear about the "slipping". If you try to downshift and then car keeps going in 3rd then I would suspect an ECU/solenoid issue. If you do feel something happen but the tranny starts slipping/losing drive then I would suspect something inside the tranny.

Since you have already done some basic service the next steps would be - check shift signals from ECU as I suggested as well as TV cable alignmemt. It may be worth just removing and cleanout out the contacts on the connector. If those do not turn up anything it may be time to pull out the valve body, disassemble and service/clean. Luckily for the MX17 tranny the valve body can be removed without having to remove the whole tranny.

[docsplace]

Originally Posted by hot_sd

Still not too clear about the "slipping". If you try to downshift and then car keeps going in 3rd then I would suspect an ECU/solenoid issue. If you do feel something happen but the tranny starts slipping/losing drive then I would suspect something inside the tranny.

Since you have already done some basic service the next steps would be - check shift signals from ECU as I suggested as well as TV cable alignmemt. It may be worth just removing and cleanout out the contacts on the connector. If those do not turn up anything it may be time to pull out the valve body, disassemble and service/clean. Luckily for the MX17 tranny the valve body can be removed without having to remove the whole tranny.

No it does not keep slipping, If you down shift to 2nd or 1st while moving down the road and try to pass someone it just will not pickup 2nd or first gear, and then slips instead of staying in 3rd, but as soon as you shift back to drive it works fine. All this happens when the trany or car has warmed up, While it is cold when you take off in the mornings especially since this last cold weather we have had in ohio it works normally. Shifts just like it should up and down. ????

I'm not really clear on the dipstick level check either, If I check that first thing in the morning the level is way high, If I check it hot running in neutral it shows normal level. After I drained and dropped the pan I lost about 2 quarts of fluid and put about the same amount back in it.
What is the procedure for checking fluid level, It has 4 notches first 2 Are cold check add and full and the second is hot add and and full, Should I be checking that while trany is hot in neutral??

Thanks for all your help.
Tom
Docsplace