Auto tranny problem

[Ivan Tuma]

Doug,

You mentioned that the tranny was overfilled .... this can cause 
problems, or so I've heard. I had an '84 quantum 5 cylinder with an auto 
(not sure which series 09x, but similar in design)
The oil from the differential had leaked into the tranny side .... 
causing the tranny to shift funny when cold (fluid was THICK) and the 
differential eventually burned out because it was dry.
I had a vibration under accelleration and eventual metallic shuddering. 
This is how I learned that these trannys have two sides.

Check the linkage between the gas pedal, throttle body and tranny ... 
sometimes these break or get out of whack, thus causing the car not to 
shift properly. The Haynes manual does a good job of explaining the 
operation of this linkage and it's proper adjustments.

Yea ... as you can see by the replies, there are many different 
illnesses with similar symptoms though.

Hope your experience is less educational.

Tschus,

Ivan

Doug Yoder wrote:

> Thanks for all the replies on this one.  I have a little more 
> information, in reply to some of the points that were brought up.
>
>> -Is there noise or shudder from the transmission under load?
>
> Can't really tell if it is from the tranny or elsewhere on the drive 
> line.  Again, only happens under moderate to heavy load at lower RPMS.
>
>> -What do the fluids look like?
>
> When I bought the car the mechanic who did a pre-sale inspection for 
> me said the tranny fluid was overfilled.  Thats the only thing I know 
> about the fluid(s) so far.  I will check the car...
>
>> -Is there any gear lube left in the differential side  (the 097 has  two
>> fluids ... on for tranny and one for differential side)
>>      -sometimes the seal breaks and the gear oil gets into the tranny
>> side, or the gear oil actually evaporates out of the bleeder valve on
>> the top of the diff.
>
> I'll check...
>
>> -Is your throttle possition switch operating correctly (this would cause
>> the engine revs to stay high after to take your foot off the gas and
>> make it feel like you got your feet on both pedals).
>
> Yes, it checks out (both idle, WOT, and TPS).
>
>> 1. car wants to go when you brake
>> As for #1, my Chevy Lumina also does something similar, especially 
>> after taking it up to 85 or so and then slowing down at an exit 
>> traffic light. I'm not 100% sure, but a friend w/ the same car said 
>> it was the tranny. Basically, the tranny wasn't down-shifting, so 
>> even though the car was only going 10-15 mph, it was stuck in 2nd 
>> gear. Since the engine has a minimum idle speed, the idle speed 
>> controller fights w/ the brakes, b/c idle speed in 2nd gear is more 
>> than 10-15mph. Mine has a similar feel, and it also feels like it 
>> will stall (and does sometimes). I also had this problem on a Pontiac 
>> 6000 which had a torque converter lockup system. The system 
>> eventually had problems disengaging and would stall the engine all 
>> the time. The solution on that was to just unplug the lockup system. 
>> Unfortunately on more modern trannies, I think the solution is either 
>> a rebuild or replacement (probly the cheaper method).
>
> I have noticed my tranny doesn't want to downshift.  For example, I 
> will be driving along the city street at ~35mph and the car is in 4th 
> gear @1500RPM , I will need to accelerate, but it doesn't shift to 
> third to give me power, even when I floor it.
>
>> 2. engine hesitates when you accelerate
>> For #2, this seems like the engine is becoming lean when 
>> accelerating. If the engine gets a lean mixture it will hesitate and 
>> feel like you lost power for a second. The ECU can probably 
>> compensate, but there is a limit and may take a while to respond. I 
>> highly suspect a vacuum leak somewhere in the intake system. Leaks 
>> are common on these cars and cause lots of trouble. You should remove 
>> and check every hose (esp. the big ones) b/c the problem probly won't 
>> stare at you in the face. Cracks are often on the underside or near 
>> the clamps. Also there are things like oil cap and valve cover leaks 
>> that can cause trouble too. This place is a good place to start 
>> running down the checklist:
>> http://www.sjmautotechnik.com/vac.html
>> http://www.sjmautotechnik.com/trouble.html
>
> Yeah, the dreaded vacuum leaks.  The car passes the "dipstick test".  
> I am pretty sure the crankcase breather hose is faulty... it's nice 
> and soft.  Unfortunately it also seems baked on, can't get it off 
> easily.  I guess it won't hurt to cut it off though, heh.
>
>> IF your car wants to do more than this then either your idle speed is 
>> too
>> high or there is indeed a problem with the transmission.
>>    So to cut to the chase, what is your idle speed?
>
> The car idles at about 1000 rpm.  It sometimes drops to 850-900, but 
> then revs back up to around 1000.  Would this be related to vacuum leaks?
>
>> But it doesn't sound like slipping, as far as holding the brake at stops
>> sounds like not slipping but Idle speed too high, did you ever put it in
>> neutral to see if  revs way high. 
>
> When I start the car (in park, obviously), the idle is around 1000.  I 
> have not tried putting it in neutral when I come to a stop sign.
>
>> If it hesitates when you push on the gas pedal does it also do this 
>> in neutral
>> with no load. I the torque converter was slipping under these 
>> conditions the
>> engine would likely rev up.
>
> Yes, it hesitates with no load.  It will sometimes even stall if I 
> floor it from idle (both in gear and in neutral).
>
> So thats where I am now.  I will replace the crankcase breather hose 
> and see if that helps the idle speed and hesitation.  I will look in 
> my bentley and see how to check the diff gear oil, and also check the 
> tranny fluid again.
>
> Thanks again,
> -Doug
>