What is "shim?" I keep reading that its good to have your transfer case properly shimmed, but cant find any info on what it actually is. I know Shep does it on all the transfer case. It's listed on the site as "Proper shim adjustment." Can someone please help me understand this? Thanks!

 

A shim will "fill in the gap" between the parts so there is no slack.

 

A shim is essentially a washer installed behind a bearing in a gear box. Shims are installed to obtain the proper gear mesh and/or bearing preload. So, if you are installing shims you need a wide variety of sizes and thicknesses at hand. This makes it difficult for the shade tree mechanic. The DIY mechanic can order packages of shims but you have to order quite a few to get the ones you need. A shop will probably just make shims.

 

In regards to Evo transfer cases, the shims are not even available by Mitsubishi for us to purchase. There are no longer any part numbers available for the ring and pinion gearset, differential and pinion gear tapered roller bearings, ACD clutch pack parts, or bearing shims.

The only way to get new shims would be to custom make some out of 316 Stainless Steel. I am in the process of doing this currently and am trying out lazer-cutting first, then plazma cutting or water-jetting. It is not cheap, and there are no "pre-made" shims available. As well, only 1 of the 4 tapered roller bearings in the transfer case have available part numbers through bearing suppliers. The other 3 were made for Mitsubishi, and the part numbers are not available.

So, with that said, I would strongly recommend sending your transfer case to a professional transmission/transfer case rebuilder such as Jon @ TRE (www.teamrip.com) or John @ ShepTrans (www.sheptrans.com).

Both these guys have the parts and the experience to do it.

I am currently working on sourcing the bearings, ring and pinion, and manufacturing my own shims, but it will be a while until they are available.

 

I am changing my pinion and ring in t case and I need some specifications for bearings preloads,gear backlash. Does anybody have any information's?