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38 Posts
Discussion Starter · #1 ·
I have an extra Zexel Torsen Posi differential. I am going to either return it or I can do a posi install for someone in my area for a small fee. I already installed one in my truck and it is awsome! :racing:

I am a little north of Detroit Michigan. Let me know.

38 Posts
Discussion Starter · #3 ·
It is pretty easy as long as you research and know what your doing and have all the right tools. If you are changing the ring and pinion it get more difficult.

V8 Member
2,831 Posts
on a scale one to ten i would say i have a 8 or 9....ten being your one smart gear head....ive rebuilt a few engines and all...the directions to put it in go step by step pretty well?? cause im actually thinking of doing this upgrade when i rebuild the rear end in my truck...200k miles its about time ..

38 Posts
Discussion Starter · #5 ·
Yes, if you have all the steps and correct tools I would think you should be able to tackel it. Search the web and get all the info you can, it does not necessarly need to be application specific. For example ( Stick your new posi diff in the freezer and heat your old ring with a propane torch, this little trick makes it easy to transfer ring gears). Some things are application specific, like torque specs and backlash. Quick run down.

parts and tools:
new posi
gear oil 85w 90
gasket sealer
dial caliper
pump to pump oil in rear end
shim kit

jack up rear and support
pull off tires
remove rear drums or disk
remove diff cover and drain oil
remove pin that holds axles in locked position
push in axle and remove C clip and pull axle out to clear diff
repeat for other axle
check back lash and record (micrometer)
remove bearing caps
gently pry out diff and dont drop it!
take out ring gear bolts, heat ring gear, and take it off
take new posi out of freezer and install old ring gear
lock tight threads and torque to spec (reverse thread)

installing new posi is the hardest part I measured the stock shims
(dont mix up left & right) then tried to install the new posi with the stock ones. It will most likely be too tight and not fit or too loose and be sloppy. This is where the shim kit come in to play. If the diff was too tight (Like mine) you need to subtract a few thousands inch (measure with micrometer calipers) from the stock shim then try again. Once it fits nice and snug you need to check back lash again and make sure it is the same as before you moved it. If it is not you need to move shims from the right or left pack to increase or decrease lash.

now to put back to together
torque down bearing caps double check lash
reinstall axles with c clips
put in axle retaining block thingy
clean gasket area and apply gasket sealer (dont need gasket)
put on diff cover
put on disk or drums
put on tires
add rear end oil

Commence to doing dounuts!

This has been a very quick rundown you need to research to fill in the gaps.
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