pjs.oregan

Anyone know where else I should be looking? It was terrible when I bought the car, much better now I've changed the (old, ruined, rubber-centered) clutch, and not really improved by new motor mounts.

There is still enough lash to feel like a proper jerk if I'm not smooth coming onto the gas in 1st/2nd.

Cheers,

edit: 84 NA, if that makes a difference

arthropraxis

Transaxle mount? Grab the transaxle and see if you can easily swing it side to side.

pjs.oregan

Hadn't thought of that... rock solid unfortunately, though

mikehayes

My trans/diff has had some play since I bought the car. Like you, it was bad before I replaced the clutch, got much better after, but was still noticable. I also have had cheap axles fail a few times, but replacing them never removed any driveline slack. Unfortunately, if it's not your clutch, mounts, or axles (unlikely), there's not really anywhere else to look except the trans. I believe the diff pinion can be adjusted to compensate for wear, but I haven't looked into it.

pfarah7

PJS: You really can't tell if they're bad until they're removed. I found large fractures in the rubber on mine once they were off the car (my 84 has two).

V2Rocket

how old are your rear shocks?
944 rear suspension is sort of bouncy when you let off/get on the gas quickly if shocks are worn out.

also i am of the belief that the long driveshaft sort of winds up along itself and releases if that makes sense.

MAGK944

pjs.oregan

Thanks for the replies all. I was hoping it wouldn't be the trans! That's pretty much the last part of the car I fear to open up.

I've had it off to do the clutch and don't remember there being anything wrong with the mounts, although I didn't inspect them in great detail. I'll look again when I do the torque tube bearings (shudder). The fluid was done about 2 years ago and I definitely had smoother shifting after that, although no change to the lash, but it certainly wouldn't hurt to repeat -- I'm in NZ and haven't seen Redline for sale anywhere unfortunately.

Rear shocks are Koni yellows of unknown age but seem in good condition & function so I'd be surprised if they were the culprit. It also feels like more of a whole-car jerk than the rear bouncing around, if that makes sense.

Edit: seems there are people selling Redline gear oil online so I'll get some of that and see if it does anything; maybe drop the transmission at the same time to get a proper look at the mounts too.

Is there some "intrinsic" lash in these cars from the driveline?

thomasmryan

you might be feeling a summation of worn components that comes with age.

are your torsion bars centered in the carriers at the spring plate? carrier and banana arm bushings intact?

are the hub and coupling splines in good shape?

cv joint mating surfaces and threads need to be acetone clean during final assembly to ensure enough clamping force.

the sound of a bad or worn ring and pinion can be loud

Jfrahm

If you watch the rear torque tube coupler you might be able to measure lash in the driveline, like with the car in 5th gear see how much rotation of a wheel it takes to move the coupler. Raise only one rear wheel if you have no LSD.
There should be some lash measurable in this fashion but a very small amount I suppose. I do not have a 944 trans handy to measure and compare. Maybe I can compare on my 968 trans, it should only be the R&P and gearset lash and should be quite minimal if measured in degrees at a rear wheel. I can't say I've felt driveline lash of note. I recall feeling a lot of windup from the rubber center clutch in my old S2 particularly if I forgot to release the parking brake but nothing like a loose clunk you'd get if a wheel was about to fall off.

...have you checked to see if a wheel is about to fall off? :-)

Van

CV joints?

Otto Mechanic

I'm with Van, if you've replaced the clutch, the transmission mount is OK, the motor mounts are OK, there's no noise coming from the torque tube, that pretty much points to the R&P or the CV joints I'd think.

Have you taken one apart? I suggest checking the outer joints first. When I took mine apart at ~80K miles the outer joints were very badly worn but not growling yet, it was easy to see wear on the face of the ?Spider? part of the bearing, the one with the five ball bearings trapped in it. Deep grooves in the face.

After I put it back together with new CVs there was no play or lash in the driveline at all. I did have the gearbox partially re-built at the same time, I put in a shorter 5th and also a rebuilt ZF LSD, so it wasn't a pure CV only rebuild, but before opening the gearbox I'd check the CV joints.

pjs.oregan

Thanks again everyone. There is noise which I think is coming from the torque tube - high pitched whine at constant load, higher in pitch with increasing revs, and then a harsher sound when off the gas. I had assumed this was the TT bearings - does it sound like R&P? I hadn't thought of that. I think when I next get a good stretch of time to work on it I'll do those TT bearings and refresh the rear suspension & CVs while I have everything apart... and I suppose if it's still there then there won't be many more places to look apart from the transaxle.

HenryPcar

How much of a slack/backlash at the wheels are acceptable. This is what I did. Put the car on stands and engage into 1 gear. Then turn the right wheel rotating back and forth. There is about 5/8" of slack on the circumference of the tire. I asked the Porsche tech and he noted that there should be some play but didn't specify how much. So is 5/8" of slack on the circumference too much ?