I currently working on getting an Arb RD157 locker installed in a Dana 44 HD with J8 tubes. The Arb kit comes with a master shim which is essentially a very thick shim. The instructions nor the exploded diagram list where this shim is supposed to go. Does this shim go on the air bearing side (ring gear side of carrier)? I tried installing it on that side but it resulted in 0” backspacing. Can any provide clarity about if this shim is supposed to be used?

 

The ARB master shim supplied is .180" thick and should be thicker than the OE master shim that came stock. The instructions all say to use the OE master shims on both sides. I haven't used the ARB master shim on the RD157. By backspacing I assume you mean backlash. The thinner OE master shim should allow decent shimming to get the backlash correct. Remember to get enough preload. Use a case spreader!

 

yes the instructions say to use the OE master shims. Haha your right, I meant backlash lol. I had new wheels on my mind at the time of writing that. Are the OE master shims the same as the shims that come with a master install kit? The housing that I’m installing this ARB locker into is a brand new housing so there were no shims that came with it.

 

It's been a while so I'm unsure of the thickness of the factory shims.
I checked the ARB master shims.
The shim that came with the RD157 is a 150352 and is .180" thick. They make another shim, 150305 that is .100" thick. The I.D. is .070" larger but this shouldn't be an issue. This should give you appropriate shimming room.