I have an '85 5KS. It just started having a problem that I'm having difficulty diagnosing. At any speed between 35 mph and 75 mph it makes a cyclic humming noise and there is a definite hinderance that coincides with the noise. (it feels like I'm barely touching the brake. On and off about twice per second.) The noise gets faster and louder with increased road speed, not with engine RPM. It also seems to be quieter when going around a steep LH curve. It occasionally "clunks" when hard down shifting, but not frequently. Could this be a CV joint, or do you think it's the final drive or transmission? Any help would be appreciated!!

Thanks,
John

My first thought was one of your wheel bearings was bad. The clunking noise doesn't fit in with that thought though. If you have a bad bearing it will make that humming noise and it will become quiter as you steer left or right depending on which wheel it is. Also the faster you go the louder it gets.

check the right front wheel bearing (humming), and the inner control arm bushings (the clunk)

Thanks for the response, I never considered the wheel bearing. I will check it ASAP.....Thanks.

In that case, we need to know the following:

-how many miles on the car?

-how many miles on the tranny?

-when was the fluid last changed?

-when was the fluid last -checked-?

-has the tranny ever been rebuilt?

The slushbox is the weakest link on the normally aspirated and turbo cars, you can prowl the junkyard and find very nice 5K's that were scrapped when the owner found out how much a rebuilt tranny costs.

If your tranny fluid is much higher than normal, that indicates the seal has gone between the tranny and the final drive, letting the two mix (which is a very bad thing).

Good luck, and let us know.

-Steve Jensen
87 5kcstq
87 5kcstqw

I've been watching the transmission fluid....It looks good, smells good, good level. I don't think it's the final drive because I shifted into neutral at 70 MPH taking all pressure off the gearbox, and it still hummed. I will pull the hubs and check the bearing tomorrow....I'll let you know. I maintain the car very well...It has 300,000 miles on it though. I hope it can be fixed because it's still a great car!!!

P.S. A wheel bearing would not surprise me too much... My rear bearing went out about 2 years ago. The bearing caps don't seal too well on 5Ks and water gets in!!