SalzundPfeffer

Greetings-

Long story short...Just graduated college and have finally got to a point in my life where purchasing a secondary daily driver/project car was relatively justifiable. I have always wanted a Porsche, and was presented with the opportunity when a coworker was looking to part ways with his 84' 944 N/A.

The car if very well suited for the daily driver, except that there seems to be quite a bit of play in the tranny. I have taken a look at everything relating to this "gear lashing" and "backlash" described on the boards (rennlist and CG). I know a lot of the threads point to the rubber centered clutch. This could be, but my symptoms don't completely point to this being the problem.

First off - I know the transmission was replaced two owners ago (probably around yr 2000). What are the chances the clutch was replaced along with it? And, do you think a rubber centered clutch was used?

Second - When I had the back end up this past weekend to change the trans. fluid, I noticed only a very small amound of play in the wheels when the clutch was in. The only "knocking" sound I heard was in the rear axle/transmission. No sounds of "knocking" or "clicking" up by the clutch when the wheels were turned.

The only backlash or bucking that I experience in the car is when the clutch is in and I am either applying or taking my foot off the gas when the car is in gear and the rpms are low. It's like I can't feather the throttle at all. I will depress the gas pedal a little bit and the engine won't rev. I will press it a little further and the engine will then respond, but by then the response is usually too much and the car will then buck. It's kind of like all or none.

Sorry about the length of the post. Just wanted to be specific.

Thanks!
-bp

MichelleJD

Chances are pretty slim the clutch was changed at the same time - they are at opposite ends of the car. Unless PO was having issues I doubt anyone went to the added work.

KuHL 951

My 83 had very similar symptoms from a failing rubber center clutch. A good way to tell is put the car on a lift or jack it up on stands. Put the cat in nuetral and remove the large rubber inspection cover at the transaxle/torque tube area. With the clutch not engaged you should not be able to turn the TT shaft very much at all. If it rotates a bit more than likely your clutch is hitting on the metal limp-home tabs. If it is tight and doesn't turn, your clutch is probably good. Next put the trans in any gear, and have someone lightly rotate the rear wheel back and forth; the delay time between the TT shaft turning and the onset of wheel movement is subjective but it shouldn't be too much.

Unfortunately too many people drive the car with a failing clutch and the ring and pinion wears down in the trans resulting in slop. You should also check the CV joints to be sure they aren't shot also from all the bucking. I test mine by setting the parking brake and twisting the driveline 1st the the outer CV and then the inner one. There shouldn't be much play with the parking brake on. If the CV's are good another test is have someone push in the clutch, parking brake set, and turn the TT shaft again, if you can rotate it easily before either CV starts to move the play is in the trans.

The slow throttle response might be nothing more than adjusting the cable so that the TPS switch engages at throttle tip-in. The cable stretches and allows too much play in the throttle pedal.

The early cars are solid if well cared for. Good Luck, I hope it turns out to be good news like a CV...but don't count on it.

DarylJ

Can you tell me some more about that? PO replaced the clutch, and I have transmission slop that I can't account for in the CVs. I was always assuming ring and pinion, but I didn't know that could be after-effects of driving with a bad clutch.

How does that occur?

KuHL 951

If a clutch is just slipping from wear, oil contamination and not banging it's really not a burden on the drivetrain, just on the flywheel and clutch disc. When the rubber center fails the metal tabs (limp-home) now rotate back and forth so the car can be driven awhile but there is no shock cushion left in the clutch. Imagine the tabs from my clutch shown below slamming back and forth from tab to tab; this puts a lot of shock on the ring and pinion as the first meshed component downstream. This one was driven very carefully for about 8K miles; many others have sheared them off completely from not being careful. No matter how you baby it, that type of shock is bad for the trans if continued over a lengthy period of time. The ring and pinion on my 83 whined pretty bad after I replaced the clutch but still shifted fine. Face it the 944/951 trans isn't known for it's butter smooth and whisper quiet operation.

JimV8

Its probably the clutch and if you don't fix it the lurching will kill the transmission.

SalzundPfeffer

I got the back end up tonight. Put the transmission in neutral. First, left the clutch out. Reached up and could not turn the TT shaft at all. No play at all. Then I wedged the clutch to the floor with a 2x4, reached up and was able to turn the TT completely without hitting any sort of resistance.

I guess I am a little confused. When you say "not engaged" do you mean the clutch pedal out or pressed toward the firewall?

-bp

JimV8

Re-reading the posts i'd say its motor related and is a hesitation. Do you know when it last had a tune up?

KuHL 951

Not engaged as in 'not pressed in'. It sounds like your clutch is OK. With the clutch 'not pressed in' and the car in gear how much play is there between the wheel(s) and the TT shaft? If you can roll a wheel more than 1" to 1-1/2" at the outer edge of the tire with the car in gear and the TT shaft not moving, the play is in the ring and pinion, the output shafts, or CV's. Just think it through and you can pin it down pretty easy. remember adjust that throttle cable before you tear anything apart. A poorly adjusted throttle cable or TPS can make the car run really crappy from a dead start. From your earlier description it sounds like you might just have a very worn trans that could run another 100K, yours wouldn't be the first to whine and still work just fine even with excessive backlash in the gears.

SalzundPfeffer

Not sure of the last tune up. But it just seems like their is no sensitivity to the throttle on the low end. It's like the engine responds too abruptly after the "deadzone" in my accelerator. When I am driving at around 30 mph in 3rd or so, I can't find a throttle position to maintain 30mph. I try to depress the gas pedal to a point where, on any other car, would be able to maintain 30mph. When I do it with my 944, the position where I think will supply enough power to maintain 30 is in the dead zone (no throttle response). I end up applying throttle too much (thus learching the car) to go over 30mph and then releasing to fall back down to 30 (thus learching the car again), and just oscillate this way.

-bp

SalzundPfeffer

I noticed that I had probably about 1-2" of play at the outer tire when I rotated it before I experienced resitance (TT movement I believe). There is also a clunking sound that only comes from right behind the left rear wheel/brake when the torque tube begins to turn (remember, clutch is good). The sound still comes from the left side even when I rotate the right rear tire too. The clunking doesn't sound like it is coming from the tranny, but more in the left rear CV area. Is there any chance that play in one of the rear CV's could produce this backlash?

Thanks
-bp

KuHL 951

That's a better description of the throttle response. Have you looked into retracking the AFM wiper arm yet. If there are any grooves at all you need to move the contact tips to a clean spot on the resistor surface. Give this a try and see how much it smooths out dead spots.

http://www.frwilk.com/944dme/afm.htm

And yes, that outer CV shouldn't have that much play in it.