I have just got new 3.89 diff gears installed and now the diff is whining pretty loud especially in 4th and 5th is this normal??????? Could it be due to uneven tyre wear on the back???????

Hmmm... Who installed the gears?? If the gear faces on the crownwheel and pinion don't "mesh?" properly your diff will whine. Has a lot to do with correct shimming I believe.

moved to the right section champ Some original photos have not been recovered yet.

3.89s whinne more then normal gear ratios because of the bigger pinion and smaller crown . Also if they are use they will whinn too , Are they new gears or Used ?

Maybe some thicker oil

Has it got oil in it ?

Who did it? Maybe it need's to wear in

wear in, lol yer right rub's, just wear that hard casing off, you dont need it anyway, lol

LOL Some original photos have not been recovered yet.

Yeah it has oil in it the gears arn't new they are reconditioned items (lapped).

the 3.89 ratio was a noisy ratio. Nissan had endless problems with this back in the R31 days and to fix the problem they replaced the gears with 3.91 ratio gears.

Quote: Originally Posted by 87calais the 3.89 ratio was a noisy ratio. Nissan had endless problems with this back in the R31 days and to fix the problem they replaced the gears with 3.91 ratio gears. precisely

What kind of problems other than noise?

nah noise was the only problem, A guy i work with was manager of spare parts at a nissan dealership back then, and said that there were cars with less than 5000km that had had 3 diff builds trying to solve the problem. The solution ended up being a ratio change to 3.91.