Stranded on I-5 in an 88 with a tranny clunk

m110 · 01-26-2009, 06:06 PM

Hello all,

I was driving back from San Diego to Sacramento last night and stopped for gas. Amid the smell of manure around Coalinga and nearing 2am after a job interview, I accelerated out of the Chevron briskly so as to not have to pass the same group of cars in the left lane yet again. (Apparently passing on the right is a big time fine in Germany but I'd still be in LA if I didn't)

I experienced a clunk with accelaration but everything was ok at speed through the gears. Clutch ok but old, shifting smooth. Lifting off the power produced a loud clunk like the engine was loose. In neutral or at speed the chassis feels fine.
I stopped and jacked up the car on the side of I-5 in the middle of nowhere. Engine mounts and carrier ok, tranny mounts ok, sway bar mounts ok.

While in 1st gear there is excessive slop side to side when rotating the wheels with a clunk. I don't have a LSD. 93,000 miles. CV joint bolts tight.
Question: What is up? Is this the pinion gear? CV joints? And if in the differential then how could I keep travelling without any problems except when coming on and off the gas to pass yet another 36' VanAmerica rented RV with some guy who normally drives a Prius at the wheel?
I ended up making it home ok. Thoughts appreciated on anything.

MotoSook · 01-26-2009, 06:17 PM

You still have the rubber center clutch disk?

m110 · 01-26-2009, 06:23 PM

I don't know if it has the rubber center disc but it is very likely. Would the clutch engagement not be impaired if it fell apart? How would that create increased slop/clunk when turning the wheels side to side while in gear?

MotoSook · 01-26-2009, 06:28 PM

Ah, I missed the side to side slop in 1st gear. Did you check the front suspension?

m110 · 01-26-2009, 06:44 PM

Didn't check the front suspension, it's definitely in the driveline. Acts like a broken U-joint or guibo joint on a rear wheel drive Benz or BMW except it doesn't have one.

ystarrev · 01-26-2009, 06:45 PM

Time to replace your clutch!

When the rubber fails you get the mechanical clunk. Kind of a 'limp home' mode.

yps

RSTarga · 01-26-2009, 07:10 PM

I agree the failed rubber starts as a clunk before it completely falls apart

88-diamondblue · 01-26-2009, 07:34 PM

I had the same thing happen accelerating past a truck. I had done a 140+ mph run earlier and I think it was the beginning of the end of the clutch. The rubber absorbs the initial shock of power starting out. If it is the clutch also plan on doing the clutch fork/shaft update kit. This is what I found.

m110 · 01-26-2009, 08:26 PM

Seems to make sense...thanks everyone. I know the rubber clutches are still available; why do people still use them? Are they smoother than the spring centered variety?

88-diamondblue · 01-26-2009, 09:29 PM

They are smoother and quieter than the spring centered clutch. I am used to the clutch chatter from the spring centered disc. At first I thought that a bolt or something loose from doing my rebuild. Just the clutch. I really didn't notice any difference from the old rubber center to the spring centered.
The spring centered clutch was used in the turbo starting in 1976. Let me know if you need one as I have a rubber centered disk that came with a kit.

The 87-89 had one of the most expensive clutches for Porsche. Just part of the price of driving the best model years of the 911

thebng · thebng's Garage

+2 on that clutch!

Bart_dood · 01-28-2009, 04:51 PM

Quote:

Originally Posted by 88-diamondblue

They are smoother and quieter than the spring centered clutch. I am used to the clutch chatter from the spring centered disc. At first I thought that a bolt or something loose from doing my rebuild. Just the clutch. I really didn't notice any difference from the old rubber center to the spring centered.
The spring centered clutch was used in the turbo starting in 1976. Let me know if you need one as I have a rubber centered disk that came with a kit.

The 87-89 had one of the most expensive clutches for Porsche. Just part of the price of driving the best model years of the 911

huh, does that mean that I have a spring centered clutch in my car as I hear chatter that goes away when I press on the clutch? I thought it was a worn clutch release bearing

m110 · 02-12-2009, 06:23 PM

Thanks to everyone. The rubber centered clutch was it. It is interesting that the mode of failure is very different than a traditional spring centered clutch and I hadn't even considered it. My driveline clunk is gone. I also updated the fork shaft with the factory repair and the action is oh so smooth! The original shaft was caput. The original clutch lasted 94,000 mi.