We have a 1987 359 Peterbilt, 13-speed and started to hear some odd noises coming from underneath today when in the high side of the transmission. It only occurs when put in high side of the transmission, yet, in neutral there is nothing to be heard. It is a very rhythmic "clunking". Probably around 3-4 seconds between the noises, so, that makes me wonder what would make that noise considering how fast everything would be spinning in the high side. I am trying to explain this the best that I can. The "clunking" gets more violent as speed increases. It also has a rattle when put in ninth gear and in the same way gets worse with speed. I appreciate any help that anyone can give me. Thanks!
So the noise is only in high range? What about when you split high range, same noise? And the noise speeds up with vehicle speed not engine rpm?
What does it sound like when you're coasting? Brian
Synchro coming apart in the range shift........ my WAG
Yes, it still makes the noise when you split the gears. It still makes the noise when coasting, if in gear. In neutral, there is no noise. Best that I can tell the noise does not increase or intensify with the engine rpm's.
what he said. have you pulled the drain plug yet. might be some clues in there.
I would pull the drain plug, then I would pull the plugs on the rears, I've seen rear end noises come through the driveline on the high/ direct side, I am guessing it's not an overdrive trans. Let us know what you find.
No, I have not pulled the plugs yet. I am actually working the truck out of town right now. I have pulled plugs in the past and it will show you some immediate answers if that is the problem. I am hear in Augusta, GA and taking the truck to Kern's Truck Parts in Atlanta tomorrow. Would you consider it wise to drive that distance with the problems I've mentioned? Have any of the users on here ever used Kern's? Let me know who to talk to.