Tony71502

BTW my trans is a brand new tremec t-5 with about 1500 highway miles on.

The car had no sounds of any sort before this.

Which implies it is caused by rear end swap, since no bearings were changed in speedo gear swap.

67mustang302

Did you run the same trans before the speedo gear swap? And if the trans was cracked open there's always the possibility that something happened. It can't be 100% ruled out. Again, you have to find out where the sound is coming from first.

08 Bullitt 2310

pinion bearing

67mustang302

Pinion bearings will typically cause the rear end to whine, with a pitch that changes as the vehicle load changes, ie it gets louder or quieter, higher or lower pitched as the throttle position is changed or the vehicle accelerates vs decelerates, or going up and down hills.

Tony71502

So when the clutch is depressed or in neutral would cause the pinion bearing to quiet down?

If no bearing was touched during dissassembly of trans then how could that cause this noise.

67mustang302

With pinion bearings when you go into neutral or disengage the clutch you unload the drivetrain, so they can quiet down.

And even if the bearings weren't messed with doesn't mean that some piece of crap didn't get into one and tear it up.

mjr46

your gonna have to start tearing it down to inspect stuff at this point.

Tony71502

Well, after putting jack stands under teh axle housing and running the car into 2nd gear at 2k....it's apparant the noise is from the pinion bushing. Both wheel bearings sound identical.

It looks like I'll be going to a 9 inch now.

Thanks for the help.

67mustang302

Don't go investing a bunch of money if you don't need to. If you have an 8.8 there's no need to spend money on a 9. Besides, sometimes pinion bearing preload just comes loose(nut backs off, wear etc), and simply tightening it up(properly, you'll have to check rotating torque) cures the problem.

AdderMk2

why would you ever consider spending almost $1500 on a 9" swap to fix a problem with a $8 bearing?