1984 Porsche 944 Shifting Issues

jacketfan89 · 09-06-2009, 08:50 AM

Alright Guys,

I've posted on a few forums and talked with a few people and we still can't pinpoint the problem. I just bought a porsche 944 on Saturday. I test drove it twice (Thursday and Friday) and had it looked at by a well known mechanic (Friday) who said that there was nothing wrong with it.

I drove it home (it drove great, no clutch slipping, no weird noises, nothing out of the ordinary.) Well I got home and we packed it up because we were driving down to the game.

About four miles down the road, I went to shift from 3rd to 4th and could shift. I pumped the clutch and finally got it to go into gear, but decided to turn around and bring it home.

When I got home I checked all of the reservoirs and everything is full on fluid. The clutch pedal still has a lot of tension to it...it doesn't go slack and it doesn't sit on the floor.

I can shift through all of the gears with and without the clutch when the car is off. Also When I start the car cold, I can shift through all of the gears with it running, but as soon as I put it in first and drive, I can't get out of first or into any other gear...I have to turn the car off and start in first just to get home.

I put the car on jack stands today and looked through the clutch inspection hole. The clutch disk was at 25 mm which is fine. The slave cylinder piston is also moving in an out as the clutch is pressed in and released. We started the car and did the same test and it still went in and out fine...which leads me to believe that it is NOT the slave cylinder either...

Also when I do start the car in first and drive there is still no slipping which leads me to believe that the clutch is okay in the car...the non-shifting has to be related to something else...BUT with all of the gears shifting with and without the clutch with the car off, that leads me to believe that it is NOT the transmission.

Can the slave cylinder fail when the car heats up and work when the car is off? I haven't tried bleeding the system yet, but someone said that may help.

Thanks a ton for any answers,

Matt

Turbo_ZA · Turbo_ZA's Garage

Can you do a crash change with the egine running - ie change without the clutch while the car is moving by backing off on the accelerator?
If you can't you are probably looking at a gearbox problem - possibly lubrication related or damaged synchro's/shift forks.

jacketfan89 · 09-06-2009, 10:36 AM

I still have the car up on jackstands until I can figure out a way to get this starter off so I can bleed the slave cylinder..Porsche made it REALLY hard to get to...lol. And rusted 19 mm bolts that hold the starter on don't make it ANY easier.

John_AZ · 09-06-2009, 10:44 AM

Try the simple checks first.

Pull off the shift lever boot and check to see if the shift rod is still connected to the shift lever. There is a "E" clip that falls off and this is common

At the rear of the shift rod is a bolt that has a security wire on it. If the wire is off the bolt may have backed out.
Do not over tighten this bolt, if it breaks you will be looking at 4 hours of drilling.

On top of the transaxle is the linkage. Check to see if all bolts are tight and the linkage moves when you use the shift lever to check all gears with the clutch pedal pushed in.

Check to see if the clutch fork moves correctly by going under the car and with a BIG screwdriver move the fork the same way the clutch slave would. Is there any binding? Is the clutch fork pivot rod all the way in? Can you tell if the clutch fork rod bearings are OK and not collapsed on one side?

GL
John_AZ
1988 924S + 1987 924S

John_AZ · 09-06-2009, 10:50 AM

To bleed the clutch slave with ANY method----------raise the rear of the car as high as your jack stands allow. If you do it wrong you could add AIR to the clutch slave and make the problem worse.

Most use a $60 pressure unit. I get good results with the Mighty Vac or similiar. This is the latest method. If you use this method, unclip the clutch master cylinder rod from the clutch pedal.

GL
John_AZ

jacketfan89 · 09-06-2009, 11:15 AM

oops...you just answered my question...lol. i had the car up on jackstands when i bled the system...and no fluid came out whatsoever...i had him hold the clutch down and i opened the valve and nothing. How do I get under the car if i have the rear end up on jackstands?

John_AZ · 09-06-2009, 11:35 AM

4 jackstands.
2 low in front
2 high in rear.

When you have the starter out poke your finger in the starter hole and look for small pieces of rubber clutch disc. If you find rubber chunks--you need a new clutch--the rubber disc has broken up and has jammed in the pressure plate.

If the PO has put in a spring disc before you purchased it, cross your fingers and hope it is a simple fix.

After you bleed the clutch and make the checks I provided, next step is to drain the transaxle and place a cloth over the pail. If you see silver metal slivers-this is not good.

GL
John_AZ

jacketfan89 · 09-06-2009, 12:23 PM

okay...I thought I would try the crash shifting just to eliminate gearbox from the equation. i took it down the street and shifted from 1-2-3-4 without touching the clutch. I won't say it was like "butter" but it was a hell of a lot easier than trying with that damned clutch. With that added to the equation what is the next step.

I am going to do the simple checks now.

jacketfan89 · 09-06-2009, 02:41 PM

All of that checked out fine. There is something wrong with the hydraulics. when i tried to bleed the system with the back raised...I still got no fluid whatsoever. I still haven't been able to get the starter out, but i'm going to try again tuesday. Then I'll pull the line going into the slave and see if theres fluid there...If not, it must be the master cylinder. would lack of fluid to the slave cause the problems that I'm having?

John_AZ · 09-06-2009, 03:05 PM

How are you able to get to the slave bleeder valve with the starter installed. How did you find the room?

When I pulled my Clutch MC in June to fix the seal leak, the MC was full of sludge. You may have the same sludge in your slave and the bleeder is clogged. Have you tried to remove the bleeder completely?

If you do not get fluid out of the slave with the bleeder removed something is clogged. Certain brake fluids do not mix, it could gum up the system.
http://importnut.net/brakefluid.htm

GL
John_AZ

jacketfan89 · 09-07-2009, 05:57 AM

I loosened the bleeder almost to the point of coming out an didn't get a drop of fluid. I have a long 7 mm wrench that fits in there and gives me just enough room to open the valve.

A guy over on 944 online doesn't think it's the hydraulics though...he thinks the bleedr is probably just clogged because the slave cylinder piston still reacts to pressure on the clutch pedal and the pedal doesn't feel spongy or soft.

I'm off tomorrow so I guess I'm going to drain the transmission and see if there are little metal shavings in the old fluid. Apparently if there are, then it's my synchros and I'm going to need a rebuilt tranny?

Could a clogged slave cylinder cause the problems I'm having or is it most likely the synchros? The clutch plate is nowhere near worn and when I can get the car to shift there's no slipping or grinding.