Help! Car is a '75 911S Targa. Driving home tonight I started to get a strange noise from the rear of the car. Sounds like something hitting or rubbing, particularly on acceleration or deceleration. However, no noises when in neutral and reving the engine, so it's not engine related. I limped home, everything seemed to work fine, but any use of the gas pedal made it much worse, going up hill was nerve racking, and decelerating wasn't good either, but steady state driving wasn't as bad.

Got home, jacked it up and crawled under it. Everything looks okay. Tried pulling on the axle shafts and everything seems tight, spun the wheels and no noise. However, three weeks ago I replaced the right axle shaft/CV joints assembly with a rebuilt. But tonight I noticed grease has clearly been leaking out and being flung around the outside of both boots. The 911 CV joints only had 4 bolts on each side and 2 pins, but the brass boot cover had 6 holes. I didn't think grease would get through where the pins are, but its looking like it did I guess I need to pull the shaft and regrease the CV joints, but I can't see anything that would cause the noise.

Any ideas what my noise is?? I'm scared to drive it as it sounds rather dramatic, but everything seems to work fine?? Please respond to my home e-mail at mueller944@aol.com (yeah I know, now that I've got a 911, I've got to work on that!)

thanks in advance,
Bob Mueller
'75 911S Targa
'90 944S2 Cab

 

Hmmmm, yet another attempt at "cyber troubleshooting".

First of all, as I'm sure you may have checked the tightness of all axle bolts? How 'bout any exhaust components being loose?

If there's nothing obvious, and you apparently have ruled out any engine internal malfunction, how 'bout the clutch fragmenting?

Check motor and transmission mounts.

Worst case scenario, and the more I think about it - ring and pinion failure in the transmission. I've been right on this one more than once!

Check it out and let us know. If it exists in all gears, during acceleration and decel, the R&P is something to consider.

 

If you recently worked on your cv's and now there is a noise and grease everywhere - I think thats your answer. Especially since you put in a rebuilt unit. Just because its rebuilt doesn't necessarily mean its been rebuilt correctly. The six holes sounds like you have later parts on an early car. My 87 has 6 bolts.

I would stop driving it, remove the replaced axle and check it out. CV's are very simple to take apart and put back together, just make sure everything goes together in the proper way. Do a search over at Pelican about CV's. There is an older VW repair bulletin that shows close up photos of a CV and how to correctly put it together. Also, torque the bolts accurately, drive for a couple of days and recheck torque.

 

similar problem with my '89 cabriolet. noise when accelerating in first or second at approximately 1,000 to 1,200 rpm. no noise at same rpm without acceleration (in neutral or revving engine with clutch in). No noise at any other rpm, no other apparent problems. No relation to mph. Noise level is subtle -- you can't hear it with stereo at low to mid level. If I go slow up-hill, in first, at 1,000 the noise is constant. HELP, I love this cab.