Hey everyone. Just did a 5speed and diff swap from a junked 83 zx into my 76 z.

The differential makes this howling, grinding noise as I decelerate, or when coasting down a hill. When I get on the gas again, the noise goes away. The noise gets considerably louder as the car gets slower, but if I simply go slow, the noise isn't even there at all. There is also no noise as accelerate.

At first I thought it might be the driveshaft rubbing the heatshield, but then I got under the car and the differential was very hot after a only a 10 minute drive (by hot I mean, I could only hold my fingers on the diff case for a couple seconds).

My first thought is that the oil level is quite low. Not sure what else could be going on.

Well, thanks to forum downtime I decided to check out the problem myself.

Pulled the diff, it was dry as a bone inside. Filled her back up with Castrol 80W140, no more howl.

Not to bag on you but, you mean you didn't check the fluid level after the install and prior to driving???? Better make sure you check the tranny fluid level. Bet you won't do that again....could have been a tough learning curve had you not checked! To error is human....someone once said!!!

Tom

Not to bag on you but, you mean you didn't check the fluid level after the install and prior to driving???? Better make sure you check the tranny fluid level. Bet you won't do that again....could have been a tough learning curve had you not checked! To error is human....someone once said!!!

Tom

This is the same question I had,,,,,,,,,,,,,,,,,,,,,,,,,,

Mike