convertor stays locked up when stoping

Randy N Connie

Registered User
When I got in to my SC auto 1990 this morning.I drove
about 1 mile.When I got to a stop sign & applied the
brakes.At about 5 MPH I noticed that the torque convertor
seem to stay locked up and started to make the motor
drag down and shutter like it was going to die.

I put this tranny and torque convertor in about 5000 miles
ago.It was a low mile tranny & torque convertor from a 93 SC.

I don't know what kind of trans fluild it had in it originally.
But after I installed the trans in my 90 SC I put some
AAMCO synthetic blend MERCON V.I think that I got most of
the old fluild out but not all.

So any one no why my torque convertor would stay locked up,
shutter and, drag the motor down.Do I need a new torque convertor?
Would this happin if I left a couple quarts of the old and maybe differrent
brand fluild.And then mix in new fluild?

After that every thing worked just fine when stoping and the motor was warm.


Randy
 
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hey i dont know about the sc but all gm cars (i know cause i fix alot of em) have a sesnor called the torque converter lockout sensor which sometimes go bad causing it to stick. also if you mixed synthetic fluyid with mineral based that is usually not good. some work together and some dont . if they dont they can gell up and clog crap and cause all kinds of problems.
 
the AOD does not have a lock up torque converter . the AODE and the 4r70w do.......but the 90 is definitely and AOD and the 93 tranny should be too.
 
I mixed the two randy and had no bad effects. I did flush it when I modified the valve body and drained the torque converter. I used mecon V also and it works great. Maybe something got caught up in the vavle body. If it keeps happening then I would investigate. My cars some times do some weird crap but then as fast as it comes its gone and life is good again. Mark
 
Randy it sounds like you had a couple of different clutch's applying at the same time. Did I understand you to say that the problem stopped later on? Possably a small crossleak in the valvebody. Before you installed the tranny did you install a shift kit or do any valvebody work at all?
All these things can cause your problem.
1. Forward clutch leakage.
2. Overdrive servo leakage.
3. Valvebody bolts loose.
4. Main oil regulator valve sticking.
Dont start taking it apart yet. Drive it some more and see if it does it again, if so try putting the shifter in L, D and D OD and see if any of those posistions effect it.
I've run into that a couple of times and both times it turned out to be loose valvebody bolts. The giveaway of loose bolts is the tranny will do it when its cold but disappear once the tranny warms up. Do you get where I'm heading with this?
Look for an Email from me and let me know if I dont get through again.;)
 
Mike The tranny is all stock.no shift kits.I do not no if the torque convertor
is stock.I bought the tranny and torque covertor and i was geuss that it had
10,000 miles or less after a rebuild.

Every thing is stock in my SC except parts that I have made,or bolt ons
I bought.For the outside.

RANDY
 
Well if the tranny has been rebuilt its possable that the valvebody bolts have come loose causing cross leaks in the valvebody which sometimes apply 2 or more clutch's at the same time. That kinda makes the car feel like the brakes are dragging on takeoff. Back in the summer that is what we found wrong on Duanes tranny if you remember.
His rebuilder got sloppy with the torque on the valvebody bolts.
Another shop told him it was toast and needed rebuilding again.
We fixed it for less than $25.00.;)
 
Mike :
I pull the SC out of the shop .I let it idea moveing about 20 ft.
Then after the 20 ft. as the SC rolled along at ldel.It started to shutter.

The trans is full of fluild.The fuild looks to be good as far as color.
I smelled the fluild and thought it had a slight burn smell.but smelled
it again and it smelled ok.

This is my first auto trans.never again.

RANDY
 
Well thats kinda hard to say because if its shuddering that can be the torque converter however it could also be 1 to many clutch's engaging and disengageing rapidly. Did it still go away after the tranny warms up?
Do you have transmission pressure test gauges?
I know what you mean about auto's, my SC is the only auto tranny car I have and I only like it because the SC has the torque to make it work good. But when they act up I dont like them!LOL!!!
 
kevenj90sc said:
the AOD does not have a lock up torque converter . the AODE and the 4r70w do.......but the 90 is definitely and AOD and the 93 tranny should be too.

Randy,
Sorry to jack your thread, But kevenj90sc AOD tranny DO have lock up converter unless someone has changed the converter to nonlock up by replacing it. When you drive you car and it goes into drive and overdrive the rpms drop and slowly climb back up due to the split shaft acting as a direct drive.

Kevenj90sc, I not trying to smarta**, but trying to set the record straight.

Randy, it sounds like mike38sc has a great starting point. I have to look at my valve body this spring. I am having shifting problems, but only between drive and overdrive.
Later
Ken
 
I haven't takin the time to drop the pan off yet.

I will do that today.And check the torque on the valve body.
And check out what I can with that veiw.

If I can't get it going.I will look into swaping out the motor &
trans for a more suitable power and drive train that will suit
my style.I have been stock pileing lighter body parts,May be time
to push my schedule up for my mods.And do the body & power.
Maybe I will get it done before the 04 SHOOTOUT.But then I will
be to fast and probably will not be aloud to play.:D

I have been trying to buy another SC block to build up the proper
way.Since it hasen't been done yet.But can't find one.I don't think people
want to see the ET & MPH put to far out of there reach.So no one will
sell me one.At a decent price! So it may be FI-SC-V-8 time .I will keep
it an SC.

I really wanted to try out my SC with the v-6 with lighter body & stock
inturnal motor.Before putting a moded v-6 in.

It seems kinda silly to have owned v-8 powered cycle,and then have
a little V-6 in my car.

Thanks for the suggestions.
RANDY
 
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Mike: I did not get to check the trans with the pan off today.
Had to have a meeting two farmers that lease my some of my land.
So maybe tomorrow I will get back to check the valve body.

What is the torque spec for the valve body.

Thanks Randy
 
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