The Stovebolt Site Forums The Shop Area Driveline Shimming 3.55 ring and pinion

I am swapping 4.11 for 3.55 ring and pinion on 1948 1/2 ton.I need some shim help the original shims where .033 any idea where to start the new shims at.Thanks

If the old pinion had a depth marked on the head (the new one should) you can figure the difference. Most old pinions have a deviation from the standard depth. Like +.003 would 3/1000" deeper then the standard for that axle. I don't know what that standard is but I might have it at home. I'll check.

From whom did you buy the R&P set?
Did instructions come with it?

If no instructions came with the gear-set, 0.033 seems like a good "starting point".

I bought the R&P from Patricks he said start at .029.I shimmed and painted it, was running on the inner third of the ring gear but i was turning ring gear not the driveshaft.I took it apart to reshim it,i never tested it turning the driveshaft so i never got good reading.New pinion head know number, old pinion head know numbers with desmal number.

Call Patricks and talk to him. He has a fixed number of additional shim from stock. I can't remember what it is. That would be your starting point.

Go down to page 12. If your contact is centered between the face and flank then your probably okay.
Its better to have it towards the center line of ring gear a bit, in forward drive, hold the ring gear and turn the pinion for forward to get pattern.

http://www.ringpinion.com/Content/H.../Yukon_Installation_Kit_Instructions.pdf

SWEET,

Are you doing a Tech Tip write-up on this?

Does Patrick still provide his installation instructions?

Those instructions were pretty good (I have installed two of his 3.55 sets). However, the copies of photos were poor, and a few instructions were very not clear.

I dimly recall Patrick's instructions including patterns/instructions for the using the red-lead (we used Prussian-blue) (Adjustment - 2). Patrick instructions here were OK. The Adjustment steps 1-14 in the Shop Manual might seem tedious and/or complicated, but they are necessary and should be carefully executed.

I am in the process of writing this swap as a step by step for our technical pages here, but it is in the beginning stages.

I recall talking to Patricks and said that a total shim depth of either .028 or so was a great starting point. Given that oldchevy's shims are already greater, I think he is best suited talking to Patrick directly. He surely has installed way more sets than I have!!!

SWEET,

We followed Patrick's hard-copy instructions. Patrick's first-try suggestion for shims worked on one job; and, a second try was needed for the other job.

I too have been lucky in the 4-5 sets that I have done, I have only had to add shims once.

Patrick's instructions say that "The installations that we have done here so far have fallen into the .026 to .028 category. That can be acheived by simply adding the .010 in the kit to the .016-.018 you removed during disassembly"