Hot Rod Forum banner

Gear pattern check

5K views 26 replies 6 participants last post by  Coolball 
#1 ·
Hi all I am working towards setting up a rear end for the first time. Wondering if I can get some feedback and corrections from everybody on how my pattern looks so far. It's a GM 10 bolt and I switched the ring and pinion to a 3.42 set of gears and used the same shims to start.

I know the current backlash is too much so I will need to tighten that up.
 

Attachments

See less See more
1
#3 ·
Thanks for the reply. the numbers say 12:41 7 5/8''

Now to me that's not the pinion depth markings. So I need to measure from the center of the ring gear to the top of the pinion for depth and compare it to?

These are OEM gears I pulled from a rear end a guy gave me for free just to haul off.

I don't have a 200ft lb torque wrench at the moment to crush the new sleeve
 
#4 ·
There should be some that are stamped for the gear ratio but the pinion depth should be engraved ie hand written with an engraver. Most reputable companies do this. other wise you will have one heck of a time trying to guess what they had it set as to lap the gears at the factory. Anyway... It looks to me like the pinion needs a shim to set it back closer to the ring gear. hope ya have a set up bearing for the pinion or its gonna get old pressing the bearing off and on.
 
#5 ·
That's okay I seem to have one heck of a time's on a weekly basis most times!

Since it's a used set I can try my best to match up the old wear pattern. I originally added a pinion shim and it made the gears bind, but it was a thick one so I'll start off with the thinnest. I'd be working towards more of a center pattern then?

About the set up bearing yes I read about that along the way and made both of the old pinion bearings interference fit where I can pop em' off by hand. Thanks for looking out.
 
#8 ·
Leave the crush sleeve and seal out during set up and set the correct prelaod. The number on the pinion will do you no good unless your using a depth gauge. If your backlash is too much now,it should bring that coast side down a little when you get the correct backlash. As it sits now it will make noise on Decel.
 
#12 ·
What should my backlash be for this type set? I have already tried a small shim on the pinion and brought the ring gear in a little and now I'm too tight at .001 which wouldn't give the gears any expansion room when they heat up.

I'm going to dive back into this tonight.
 
#17 ·
Coolball said:
It's a GM 10 bolt and I switched the ring and pinion to a 3.42 set of gears and used the same shims to start.
Using the original shims that were correct w/the old R&P are a starting point, but you'd like to start out w/the same shims that were used w/the same R&P you are installing. In other words, if you have the shims that were used w/the 3.42 gears, that is what you want to start with, or the equivalent new shims.
 
#20 ·
Not sure what you mean by "it's not torqued yet" ...The pinion not being torqued will only change the preload of the pinion bearings. However if the carrier is not torqued this will change the backlash and pattern.. you always want to make sure the carrier is torqued during setup.
 
#21 ·
The pinion nut isn't torqued yet. I was thinking not only will that procedure preload the bearings yes but also open the backlash up those .002'' ideally from the compression of the bearings. I have been torquing the bearing caps on the carrier during setup.

I loaned out the proper torque wrench from the parts house so I can finish this up. Just need to know if the pattern is agreeable? It is pretty centered on both sides with the coast side a little towards the heel which I have read is acceptable.
 
#22 ·
In theory the pinion nut should not change the gear pattern at all, only the preload of the bearings. It uses the crush sleeve to do this as well as hold things where they need to be. So the nut wont really be torqued. Just put red lock tight and set to the correct bearing preload. Differentials without a crush sleeve use torque pinion nut.
 
#23 ·
That's the same theory I have read and this setup does use a crush sleeve versus an adjustable pinion nut. Everything I have read also says after torquing the crush sleeve to recheck the backlash and pattern as it might change too. Guess I will go for it and see what happens :thumbup:
 
#24 ·
ALL Differentials will have a crush sleeve or a solid spacer to set the pinion brg preload!!! There is NO such thing as a "adjustable pinion nut".

You NEED to keep all your preloads and backlash correct and the same during set up.

During set up I will leave the crush sleeve and pinion seal out and set the preload with the pinion nut only. When the setup is complete I will pull it apart 1 last time using the crush sleeve and seal.
 
#25 ·
Not adjustable pinion nut as I stated, I was thinking of the preload shim type design. Whether or not it uses a crush sleeve or solid spacer is beyond my knowledge.

Sounds like I hosed the bearing preload process. Err, I put the same amount of torque on the pinion nut each time I set up but it sounds like maybe I had it too loose. I tightened it until the pinion was snug and resistance was felt while turning.

When I did final install, I installed the new bearings and crushed the new sleeve to 200 ft lb as required. It slightly moved the coast side pattern a bit towards the toe but not much from where is is in the above photos. It's pretty much a match to the used pattern in the gears.

It also ended up opening up the final backlash to .095'' which is in spec.

Hope I didn't screw this up....
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top