Rear End Bad--Gear Ratio Question?

[corning_d3]

The best way to check backlash/pinion depth is to mark the ring gear with paint that comes with a new pinion/ring gear set. If your pinion is riding too close to the heel(too far out) you'll be able to see it in the mating mark. It is possible you switched the shims around using a thinner shim on the drivers side of the diff. Having to tap the shims in is normal..

[maxwedge]

Can't guess with tooth contact and backlash, the difference between .005-.007 preferred, to .015 is hard to tell by hand, you really need an indicator set up to check this, also there is special marking oaste used to check tooth contact, do drive and coast side.

[brehmster]

Well all went well with install. Used marking paint as suggested and gears believe it or not aligned pretty well. Not perfect, but good enough according to some of the example pictures I found online. Anyway this was all for not as the pinion bearings are bad and will need to be replaced. The rear end is much tighter and quieter but still have noise during acceleration. So I guess I am going to tear it down one more time just for practice. :}

May leave it to a professional to do this time. It has been a great experience, and I appreciate all the feedback.

[Treblig69]

You have to get a dial indicator to check the backlash. The pinion does have a crush sleeve but since you didn't remove the pinion and the pinion bearings are OK then that part should be alright. Once you have the ring gear "in" and the bearing caps torqued you use a magnetic base indicator to check the backlash. The backlash is adjusted by moving/replacing shims from one side to the other. The pinion hasn't moved so you only have to make sure the ring gear is not too far from the pinion gear (too much backlash). You'll get a clucking sound if you have too much backlash just like you did when the bearings were bad. It's not really that hard to do if you know what and how to do it. The backlash checks for the "total" amount of clearance between the pinion and the ring gear. I don't remember the backlash spec but it's probably around .002-.005 in. The dealer or a mechanic can tell you exactly how much you need.

Treblig in Tx

[maxwedge]

backlash is 005-007, good advice on the issue, treblig69! Measure at 120 degree intervals, use the lowest setting another words, not under .005. at any point.

[Treblig69]

Thanks MAXWEDGE! My only fear is that brehmster didn't check the pinion bearings for wear. With bad ring gear bearings he will certainly have some some trash (metal particles) in the pinion bearings (we all know what that does) so it may just be a matter of time. I always go ahead and replace the pinion seal when I tear down the rearend especially if it has over 80,000 miles or so. Pinion seals always end up leaking sooner or later.

[RahX]

curious to see exactly how the contact pattern was. and did you load up the diff pretty good when you checked it?

[brehmster]

Hey guys,

Well don't say u told me so! Pinion Bearings, as maxwedge/Treblig69 virtually predicted, are bad! Noisy on accel

@ this point I have in my hand new pinion bearings, crush washer, and seal.

What would be the correct way to go about this since I did not originally document my diff. removal. Should I just remove everything and reinstall with current pinion shim setup and then use the paint method to check for proper wear??? Would it be best to go ahead and measure for backlash before disassembly and again at reassembly or does it really matter @ this point to measure anything?

[RahX]

well new bearings are going to probably make the backlash tighter. all you can do is measure it now and when it goes back together and check the pattern. make sure you use a prybar and load that case up so you get a good pattern.

[Treblig69]

I doesn't matter. Once you take out the pinion it's like starting brand new except for being able to determine you new setting based on the old setting. In other words you could have used the old gear shim setting to calculate your new shim setting but since you had/have so much wear it probably will be just as easy to start from the beginning. They say if you have the new pinion crush sleeve pre-crushed it's alot easier. Any machine shop can do it. When you install the new crush sleeve you will have to basically crush it using a long breaker bar when you install the pinion nut unless you have a good sized air-tool. In order to overcome the initial crush sleeve stiffness it takes temendous torque and that's why it's best to get it pre-crushed. It won't cost very much but you won't have to kill yourself during installation. Once the crush sleeve is pre-crushed it makes it much easier to for you to torque the nut to the required torque/setting. The pinion doesn't really take shims or adjustment it takes pre-load. Once it is properly pre-loaded it won't ever move again. All the gear mesh adjustments are made using the ring gear shims (left and right). I believe the pinion has numbers on it that help you get the correct pinion depth. Either way the majority of the gear mesh adjustment is made using the ring gear bearing shims. It's kinda hard to go into all the detail on this site, besides I'm sure somebody has a web site for you to get all the details. Make sure you wash-out the inside real good after you remove everything. It doesn't take much to destroy new bearings. Keep your old shims as a reference. Make sure you lock the pinion so that it can't move at all as you set the backlash. If the pinion moves (and you don't notice), your setting will be wrong. Using a magnetic base dial indicator you simply stick the magnetic base to the rear end and make sure the indicator shaft is perpendicular to the gear tooth face. If the shaft is not perpendicular to the gear tooth the reading will not be accurate. With the indicator in place and the pinion locked-down you simply rotate the ring gear back and forth to see how far the indicator moves between touching the pinion teeth in one direction and the other direction. Actually it's easier to move the ring gear all the way in one direction then "zero" the indicator and then move the ring gear as far as it go in the other direction. This way you can read the movement more accurately.
I don't know how many characters are allowed on each response so I'm gonna stop for now. Does anyone have a web site with all the directions?

Treblig inTX

[Treblig69]

one more thing...Make sure you wash the new ring gear bearing as they will have collected some metal particles from the bad pinion bearings. Wash everything including the spider gears. Get as much dirt and metal out as possible. You will also find metal laying in the bottom of the pinion housing area, it might be hard to get but it's gotta come out. There will also be some trash in the axle housings but it usually says put (the cleaner the better).

Treblig in Tx.

[brehmster]

Thanks for the info again Treblig69.

That really cleared it up in my mind. Makes alot more sense now. I have found a few good web sites for this and here is one for anyone else needing good info and some different tips on rear end work:

http://www.2quicknovas.com/happyrearends.html

So from here I will make sure and clean everything again really well and will see about getting the crush washer precrushed...and you say they can set the 25in/lbs before hand for you? Either way your just saying it is easier to have it pre-crushed.

Then once pinion is installed just make adjustments with the left and right differential shims as needed for back lash adjustments. Well, sounds easy enough. Thanks a bunch guys and will post back again soon.

Brehmster

[brehmster]

Well I finally got a free Saturday to work on the rear end. Put new pinion bearings in and it all went well until I looked on the ground and seen my new pinion seal laying there. I think they recomend that you put this on first, so to anyone else go slow and dont forget the SEAL!!. Lucky for me I had an extra crush sleeve and was able to start that process over again. Also when I was putting my new bearing races in I was able to use the old race to pound the small one in, this one was easy. The big one gave me some trouble cause u can't get a hammer in the housing, so I thought about using my air chisel with a dull flat bit. It went in very easy with no damage to the race, just work your way around the race little by little and it goes in super easy with very little effort. Anyway it all went together very nice and is working great for me at the moment.


One thing I can recomend to anyone else with a noisy rear end and thinking about just changing certain bearings is to just do them all at the same time. Its a little extra work, but you will be so glad you did. I have torn down my rear end twice because I thought that my pinion bearings were good(they were not), and if I would have done them all at once (like some suggested)I would have saved myself a Saturday. So again thanks to all for there suggestions and help!

Brehmster