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lost overdrive?

L

lbc187

New member
While accelerating (my 2002 GP GT 127K miles) to pass at about 70mph recently, I had a sudden and temporary power loss and heard almost a squeaking sound from engine compartment. I then
noticed that if I took my foot of gas pedal, rpms would immed drop to near 1000 rpm...and when I then tried to moderately accelerate, engine would race back up to 3,000ish rpm before producing any more acceleration (and rpms required to travel 60mph are now about 3,000 rather than normal 1900ish). There is no check engine light. On the plus side, car seems to drive normally in 3rd gear (albeit w/less fuel economy etc). I do expect to go to a tranny shop to get a def diagnosis, but does this just sound like a simple loss of 4th gear? Could I expect to get a lot more miles out of the car if I just keep in 3 from now on, as cost of fixing wouldn't be worth it

Thanks for any insight.
Tom
 


Unfortunately this is a very common occurrence; you probably just lost the 4th gear clutch hub. This is a well know problem that has been corrected in newer GPs. You need your tranny rebuilt. I would fix it, these trannys and cars are actually pretty good baring a couple oversights.
 
would love to fix it b/c I like car so much, but I've got other issues besides tranny that make me think its lifespan is limited. If its just the 4th gear clutch hub failure, can I expect to drive around normally in 3rd gear, or should I expect other tranny problems in my future?
 
It's the 4th clutch hub. You can fix this in about 20 side cover bolts, 10 channel plate bolts and 2 channel plate gaskets plus the 4th hub.

The downside is dropping the cradle and drivetrain to do it. I've done a bunch of these types of things lately. Overall it's easy and just time/effort. If you can turn a wrench you don't need the trans rebuilt fully. You only need to change the one part and two gaskets that are needed to get to it.

I have done so many lately that I can be into the trans in under an hour. :eek:
 
Manhattan but commute to norwalk CT. Assuming I don't get it fixed, is there any harm in continuing to drive in 3? is 4th gr clutch hub sort of independent from rest of transmission?
 


I have the same exactly problem. Anyone in Cincinnati area can help change this 4th gear hub. I m in a very tight budget and looking around for a used trans to replace but even though with labor can't go less than 500-600, and you have the risk the used one to be bad also..:(

BTW what's your gas mileage with 3rd gear? Mine is about 20mpg mixed.

thanks
 
I have this exact same problem in our 2000 GTP. I am fairly good with wrenches as I drop and swap motors and trans axles on Fiero's all the time. I just finished 2 swaps that needed new engines one requiring a new clutch along with the new engine.

Is there a good write up some place on what needs to be done to drop the cradle on this. Can you leave the trans attached to the engine and cradle. From the sounds of this, I just need to pop the side cover same as if I was doing a TCC on a 125C Auto Trans in a Fiero, then from their dig a bit deeper. However the "bit deeper" is where it gets fuzzy. I unfortunately don't have a 4 post hoist, just a cherry picker that I use to lift Fiero body's up and leave the subframe on the ground.
 
Um?
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Ya I saw it was a few years old, but some of the posters in here are still active on the forum. I figured instead of starting a new thread, I would ask in an old one. I am a forum admin on another board and hate seeing 20 zillion threads on the same topic. So I hit "search" BEFORE I hit "new thread" and found this one.
 


I just dropped my cradle and removed my tranny today.

It's not that hard.

The best write up is here: http://www.grandprixforums.net/how-remove-transmission-35485.html

A couple of things Bill left out:

1) You need to remove (or at least unbolt) the sway bar (at least I did) to remove the power steering rack bolts
2) You need to remove the air filter box and inlet elbow (to the MAF/TB) to access the tranny-to-engine bolts
3) One of the bolts that mounts the tranny to the engine is also a ground stud. You need to remove the wires (15mm) before you can access this bolt. And, it didn't look like a bolt on mine - I put a socket on it and it grabbed (to my shock, after 20 min looking around for the 4th bolt)
4) the picture Bill has posted of the backside 18mm bolt (from engine to trans) is a little misleading - notice he has the engine out and manifold off. This bolt is a straight shot from the passenger wheel-well (with a long ass extension), but it's much closer to the bottom of the trans than it looks (at least to me) in that picture Bill has. I kept looking for this bolt near the VC but it's much lower than that.
5) disconnect your cooler lines (obviously) - I did it at the trans and not the radiator

Also other things (re: how I did it):

1) I took off the hood - I have the engine supported from above on a roof joist in a barn.
2) Put down some sort of towel when you remove the tranny. Even when you drain it completely, the TC will leak all over the place
3) The gear selector linkage is easier to remove from below (I think). I took a long flathead screwdriver and hit the back of it with my palm - it popped right off (after 10 min of fighting it from above)

I did the project in two steps:

Day 1: tear it apart down to removing the axles (about 2 hours)
Day 2: drop the cradle, de-couple engine and trans, remove trans (about 4 hours total)

I don't have air tools, I could have sped things up with those.

The hardest part of the whole process, I think, is getting the damn bj's loose.

All in all it's not that bad. Be prepared to break lots of the little plastic wire/pipe/inner fender clips.
 
Thank You SJAndrew for the link and the extra info. Sounds like it is pretty straight forward and very similar to pulling an auto from a Fiero. With the obvious change being we don't have to deal with power steering in the rear, just toe link rods. (same as tie rods in a front drive car, just solid mounted to the cradle at one end)

My next thing is to start sourcing the 4th gear clutch pack locally. There is a guy in our club that rebuilds transmissions professionally so I'll give him a call for parts. Maybe even ask him to give me a hand with it once I get the trans out.
 
Yep bringing this one back from the dead. I have a question:

BillBoost37 said:
It's the 4th clutch hub. You can fix this in about 20 side cover bolts, 10 channel plate bolts and 2 channel plate gaskets plus the 4th hub. :eek:
Click to expand...

BillBoost37 did you mean that I have to buy replacement bolts as well as gaskets, or merely that I have to remove all those bolts?

And another question - where should I get the new 4th gear clutch hub from?

And here is my contribution to this thread - there is a link at post 12 that no longer works because I think our forum hosts have re-arranged the thread filing system. I was able to hunt down the thread again so here is a link that will work for instructions on removal of the tranny: http://www.grandprixforums.net/threads/35485-How-to-remove-a-transmission
 
Just the channel plate gaskets and the 4th hub. It'd probably be a good idea to change out the TCS and PCS solenoids while you are in there.
 
Booba5185 said:
Just the channel plate gaskets and the 4th hub. It'd probably be a good idea to change out the TCS and PCS solenoids while you are in there.
Click to expand...

Yup, what this guy said.

You can do this in the car, jack up the left side as high as you can, support it and drop the cradle down. Tie up the steering rack so that the shaft doesn't come apart.
 


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