Rear end rebuild

[ackland3]

Hi I am rebuilding the rear end in my 1985 k10 4WD with a 3.73 gear ratio. I have discovered the ring and pinion are shot along with the bearings and spider gears. Would the spider gears out of a 12 bolt rear end work in a 10 bolt? Does my gear ratio affect the spider gears at all so say would spider gears out of a different ratio work ? I have a couple of gm rear ends laying about but the ratios are different... also would the axle out of one of those work so long as it was six lug?

[bake74]

      All your questions could be answered this way.  If the spline counts were the same on any piece you want to swap and the size is the same, then they should work.
     I am assuming you don't want to get new parts while you have some laying around.  What are you going to do with the bearings and races if the rest is junk, those should be junk also.  Sometimes you can get a complete master rebuild kit for those GM axles pretty cheap.
     The last time I checked it was like $280.00 plus shipping for a master kit.

[DnStClr]

Not to put words in your mouth, but it sounds like you want to mix and  match gear sets. and the answer is-no. You don't want to mix and match gear sets. Gears develop a wear pattern. When you change the set-up of the gear partnership you are very likely to create a new wear pattern that causes lots of clearance issues between driver and pinions. For that reason, you find the dif gears sold as a set.

[ackland3]

I since ordered a rebuild kit with a new ring and pinion along with bearings shims marking compound etc. plus new spider gears. Now my biggest question is what should my backlash be for the axles? I've heard horror stories of them grenading if they are off even a little bit...

[bake74]

     Check out this article.    http://sethirdgen.org/10bolt2.htm

[Jason S]

Did your ring and pinion come have setup specs supplied?

Do as much research as you can on reassembling a gear set. There are electronic copies of factory service manuals on the forum as well as many websites with lots of information. The early 70's manuals (i.e., 73 and 74) provide a very good fundamental working of the various components, including the axles.

It's been a about a decade since I rebuilt an axle, but the nutshell version is the gear set should be marked as to what is required for proper setup. You would add or subtract shims on the carrier bearings to match the gear set requirements and then 'crush' the crush sleeve to obtain a proper marking on the ring and pinion.

Here is another site with a photographic write-up of a rebuild: http://www.truckmodcentral.com/forums/f168/gm-10-bolt-rear-gear-install-setup-11732/

[ackland3]

I am really only having trouble finding out what my backlash should be.... I have heard 6-10 thousandths and i just found out my grandfather (bless his heart but still) set it at around 20 in accordance with an old book he had then drove it around 5 miles and said that it ran "hot" I told him not to drive it or anything until I found out the actual specs......


1985 k10 305 engine 28spline axles 10 bolt rear end 3:73 gear ratio 6 lug wheels

[Captkaos]

Nothing on a 12bolt will work on that 10 bolt.

[78BIG-TEN]

Ring gear backlash 5 to 8.I like to get close to 8.