NP205 Rebuild help: Idler gear shims

[JMD]

Hi all,
I'm in the process of rebuilding the NP205 in my '68 K20 and I can't seem to get the idler gear shimmed properly. When I took the assembly apart it slipped out of my hand and pieces flew everywhere, so I have no idea which shim went where. I do know there were three shims. Two thin, and one that was a little thicker.

I know that the shims go between the bearing and the spacer. My question is, does it matter which side of the spacer the shims go on?

I played around with putting the spacers in different spots and it didn't seem to make a difference. However, I was never able to get the end play within spec (<.002"). I'm assuming it's okay to remove a shim at this point because the bearings are a little more "broke in", correct? I have about .010" of end play as it sits.

Any info is appreciated, thanks.

[jocko]

I don’t know the answer - but in case you haven’t yet seen it, JBClassix 205 rebuild thread is extremely detailed. Either search for him or go to the 4x4 forum and it is pinned in the FAQ, I think. It may have an answer for you - not certain though, it’s been a while since I’ve read it. Just wanted to mention in case you haven’t seen it.

[randy500]

Why wouldn't u buy new bearings and shims, your not interested in it working properly and not making noise?

[Thegoose74]

I’m getting ready to rebuild mine as well. If you search on YouTube there is a three part video series that is very detailed on how to disassemble, inspect and reassemble it. I think the last video shows how to put the idler gear back together

[kwmech]

All the shims go between the bearing and the case on the nut side of the shaft. So you have to put the gear in with the shims stuck somewhat to the bearing with a touch of grease to hold them in place the shove the shaft in from the bottom all the way through without damaging the shim, then tighten the nut to about 100 lbs torque. Check endplay, you don't want or need preload on the bearings and you don't want it excessively loose to where the gear goes back and forth in the case.

[JMD]

Thanks for the responses.
I ended up doing a lot more research and it appears that the shims go between the bearings and the spacer, however it doesn't matter which side of the spacer.

I had to use different shims to get the end play where I wanted it. Luckily the NP205 I was robbing the input shaft from had the correct sizes, so I was able to finish the project without waiting for more parts.

For those who are interested, here some links to the sites that were extremely helpful as I tackled this project.

https://youtu.be/y_npR9NxgR8

http://www.wideopen4x4.com/NP205RebuildGuide.html

http://67-72chevytrucks.com/vboard/s...d.php?t=469726