901 Transmission Reverse Noise

[patssle]

This is my 914 transmission (5 speed side shift) but I know there are similarities so posting it here hoping to find a tranny expert.

I can't seem to find the cause of my tranny making noise in reverse. I have replaced the cage and needle bearings on the reverse gear idler. It does not make noise in first or any other gear. I put the tail cone back on without the idler gear to test - no noise. The gear teeth on the idler are a little grinded on the side from nicking reverse when shifting to 2nd a couple times over the years but the gear teeth that engage the 1st/reverse slider look fine to me (see photo below). The 1st/reverse slider gear teeth look good. 1st/reverse slider seems to be sturdy on the guide sleeve. The car shifts fine in all gears.

Here is what it sounds like turning the wheel by hand: http://www.patssle.com/trans.mp3

Any thoughts?

[patssle]

Bump!

[Jcslocum]

That gear looks hammered. Have you filed off the edges of the damaged areas at all?

I may have a reverse gear in my box of bits and will look later in the day. Dr. Evil (Mike Lesniak) is the 901 expert and may also have parts for you.

[john walker's workshop]

Straight cut gears are noisy. That wear on the leading edge is fairly normal, being it's not syncronized.

[patssle]

Yeah that's what I thought with the edges being nicked a few times. But the area that the gear teeth mesh with the slider are fine - I wouldn't think the edges have an impact when the gears are together?

Straight cut might be noisy but this sound started after I nicked reverse when going to 2nd gear - the car makes a noise when reversing that wasn't there before.

I've tried to get in contact with Evil but it seems he's been offline for a while.

[Joe Bob]

No syncro on reverse. Most if not all whine in reverse.

[john walker's workshop]

When you had the end cover off, did you check the clearance between the reverse gear and the slider teeth when the trans was in neutral?

[patssle]

I don't think that's possible in the 914 901? The reverse gear idler comes out with the tail cone as do the bearings and shaft.

[john walker's workshop]

You have to hold the reverse gear and it's spacer against the intermediate housing when you set up your shift forks. Probably didn't do that, eh?