Something in the drivetrain is slipping!

[kpaske]

OK, I'm moving this to another post because I'm not sure my problem is what I originally thought. I posted earlier that I thought my clutch was slipping, but now I'm not sure if that is it. Here are the symptoms: whenever I accelerate, the RPM's go way up, but the car only accelerates slowly. After the RPM's spin up, it eventually "catches" and the car begins accelerating a bit faster. If I drive more aggressively, it's a bit less noticeable, but if I drive it gently it seems like something is slipping quite a bit. Could someone please suggest what my problem might be? As I mentioned in an earlier message, I just recently dropped my tranny to replace the rear main seal, so it could possibly be anything between the flywheel and the drive shaft. The gear lube is topped off and the hydraulics have been bled. Any help would be appreciated!!!

[Norbie]

There is nothing in the drivetrain that will slip apart from the clutch. Possibilities include an excessively worn drive plate, broken pressure plate, clutch hydraulics playing up, or oil on the clutch.

[kpaske]

Well, I'm not much of a mechanic, so correct me if I'm wrong - but doesn't the clutch only grab when you're changing gears? It doesn't slip when I'm easing the clutch out, but once it's released completely and I'm giving it some gas, the RPM's rev up, but the car doesn't accelerate as quickly as the RPM's are rising. I don't think the parts are excessively worn or broken, because it seemed to operate OK before I dropped the tranny. Oil on the clutch is a possibility, although I was careful not to get oil on it, so if that's the case, oil must be leaking in there some how. What do you mean by clutch hydraulics "playing up"?

[BillyM]

any time the pedal is depressed, the clutch plates are seperated, when you let up it connects it all...

you have exactly what norbie said.

--BillyM

[williamb82]

and if something is leaking, prolly the rear main seal. but yeah, sounds like a slipping clutch. btdt with a stage 3.
william

[DKJones96]

what about the sub-clutches in the transmission? the ones that take over till the synchros dog teech lighn up? maybe worn?(just a shot in the dark)

[Norbie]

Once a gear is engaged, it is locked solid on the shaft and cannot possibly slip. You'll smash the gears to pieces before anything like this happens (trust me, I did it on the weekend for the second time). As I said above, in a car with a manual transmission the clutch is the only component that can possibly slip.

Kpaske, if you have air in the clutch hydraulic system it can sometimes prevent the clutch from engaging properly. A badly worn master and/or slave cylinder can do the same thing. It's pretty uncommon though, so a problem with the clutch itself (as outlined above) is the more likely possibility.

Did you thoroughly inspect the drive plate when you had the clutch apart?

[DKJones96]

the synchronizers are what i'm talking about

http://auto.howstuffworks.com/transmission6.htm

that explains what they are and what they do.

[BillyM]

No. It will grind the fuck out of the ends of the gears if its only into the synchros not all the way in gear. If anything but the clutch is slipping, you will hear it, and I mean HEAR it....

I have driven and even autox'd 3 different cars doing exactly what he is explaining. Its a slipping clutch no doubt. They engage ok, but will slip out at rpms...


--billyM

[Deanfun]

i've had my 85 slip ONCE now (granted i'm using an old used clutch) and it slipped long after i had engaged it. A good WOT throttle in 4th from about 2500rpms up cause it to rev a bit faster than it accerelated.

it happens.