The Stovebolt Site Forums The Shop Area Driveline wining when coasting

i have a 1954 chevy with the enclosed drive shift,it runs fine, noted when i let off the gas the truck makes a wining noise as the motor slows the truck down,any idea what it is.i cann't tell if it is the rear end our the u-joint,it sounds like it is coming from under the seat,any ideas will be helpful.

Sounds like a bad pinion bearing. You could check the transmission fluid to make sure that it all hasn't went to the rear end. If it is real low check the rear end and it will probably be overfull which will tell you that the seal for the torque tube is bad.

Hmmmm- - - - -is it making merlot, or port, or maybe pink chablis?
Jerry

It is very unusual for the coast side of the pinion bearing to fail. It is always the load side I see fail.
It is possible some one has worked on the rear end and set the back-lash wrong.

My first thought was rear-end. But just curious, does it make any difference if it is in gear or kicked out of gear? Trying to get transmission eliminated so he can focus on differential. Is the whine coming more from rear of truck or middle?

Driveline noises are very difficult to locate, particularly with a torque tube since the noise will always transmit itself up the tube. Try driving the truck in a pull/float/coast situation and see how much noise difference there is. It's possible the coast side of the ring gear is worn, or the front pinion bearing has failed. My Motor Magazine repair manual shows a ring gear backlash specification of .005" -.007".
Jerry

Turn up the radio until it gets worse. By the time it gets loud enough to hear over the radio, you will likely be able to pinpoint where its coming from and tear down and fix the appropriate part. My truck whines, and leaks oil except when it is turned off, and out of oil.
Carl

The good ole boys used to put saw dust in the rear-end to try to stop whining noises. My guess is that oak was better than pine?

oatmeal works well, Quaker brand ... or maybe that was in the trans

Bill

thanks for your help
the wining sounds like it coming from the middle of the truck.
when i push in the clutch the wining sound is not as bad but still her

thanks for the help
the wining is not as loud when it is out of gear and sometines stops,i have a question about the plug that go in the rear end,when i took them out they were in deeper,when i replaced then they would not screw in as far .do think that has anything to do with it,i removed all three and replaced and none with back in as far.

when i put the rearend in i removed the 3 plugs and drain the oil,when i replaced the plugs they wouldn"t screw in as far ,do think that has something to do with it.
thanks

thanks jerry
i have noticed that when it is pulling no wining,when it is coasting in gear it wines loud,and when it is coasting it makes a low wining noise,any ideas????
thanks

Big D

Did the whining occur before you removed the 3 plugs? These plugs hold the pinion bearing in place and it is possible that by removing all 3 you changed the backlash which would cause a new whine during driving.

I think that SWEET has it. If you removed those 3 plugs and they didn't go back in the same place something moved. You should take the rear cover off start with a indicator to see what your backlash is.

Bingo! The pinion gear has moved forward and totally disrupted the tooth contact pattern. The 3 setscrews sbouldn't be disturbed unless you're dismantling the gearset. It will probably be necessary to remove the axle/torque tube assembly and drive the pinion back into position by tapping on the end of the driveshaft now.
Jerry

It is described in the manual about not touching those set screws. When I first read that, it scared me to death and I became afraid to even look directly at them, let alone touch them. BIG D, while you have some extra work to do now, you may well have saved many others from having to do the same. When you get done, you will have bragging rights few of us have.
Carl