Updated: REinstalled 3.27 ring/pinion

[matthew]

I got it done yesterday, kind of involved, somewhat tougher than I had anticipated. Excellent results, good pattern on the gears with the marking compound. I love the difference off the line, however...

Backlash measured 0.006" on my dial, I had heard that spec was 3-8 thousandths, so I went with it. I have some gear noise above 35 mph or so, especially under load.

Is gear noise from excessive backlash? If so, what is the recommended backlash? I have plenty of time and shims, and my pinion depth and preload seem good, so I believe that the carrier just needs moved over a little (maybe 6-8 thou). What do you think guys?

By the way, 3.27 seems to be an excellent street gear. I got a very noticeable improvement without revving the piss out of the Loveboat on the highway at 70.

[Blaze86Vic]

Did you do a contact patch test? That is when you paint the surface of the gear and see how the ring an pinion gear are contacting? Whine can happen from too much or too little, or a "defective gear". Defective gear is not that big a deal.

Here is a pic of the pain on my gear.

[matthew]

my pattern was similar to yours but a little more elongated heel to toe.

[Blaze86Vic]

The pattern that you see is my reverse pattern, and before I finished adjusting the carrier spacers. My finished foward patter was a little funny, but good enough. It was from heel to about 3/4 of the gear. Couldn't seem to do much better than that, under very light power 45-50mph I have a slight whine, other than that nothing.

[N A]

What gear did you have in it before the 3.27:1 ?

[matthew]

2.73

[matthew]

okay, I opened the cover up and rechecked the backlash. It opened up to 8-9 thousandths. so I reshimmed and reinstalled, also added a copule thousandths preload to make the carrier just a hair tighter. The carrier is now quite tight, and had to be tapped in with a rubber hammer. the backlash is now 3 thousandths. And my pattern looks likes this:
drive:

Coast:


I have spent hours looking at charts and studying patterns and they still don't mean shit to me. For anyone who knows (ahem Scott, Blaze etc.), Does this look good to you? It seems allright to me, but before I button up and have to redo it again, I would welcome all opinions.

[Blaze86Vic]

That doesn't look very good. I can't really tell much by the coast pic, can't make out the patter very well. It looks like the pinion spacer needs to be thicker. From those results adjust again. It looks like you are getting a very shallow contact patter on the drive side.

Here is a good site for help with interpolating the patterns.

http://www.drivetrain.com/ringpinioninstal.html

[matthew]

new pattern after adding some pinion shim:
drive:



coast:



I can't seem to do any better, any opinions? I think it is somewhat improved, I'm tired of fucking with this motherfucker. I recommend to anyone that is not a pro, DO NOT FUCKING TRY THIS!!!

If you pulled it off and your not a pro or were'nt helped by one, you got lucky, period.