Hello all,

I just wanted to write my experience with 4.10 install from factory 3.27.

I ordered from AM the Ford 4.10 gear and a Yukon 28 spline differential along with the entire install kit. New bearings, shims, etc.

I have no past experience with gears.
I installed the pinion with the same shims from the old.

I could not get enough backlash on the ring gear using factory shims (or so I thought) I ended up using shims from the kit to get the ring gear backlash correct.

I drove for a few hundred miles and was noticing a slight whine between 40 and 50 while I was coasting only.

I searched and searched and read more pinion shims for higher gears so I thought the pinion was not set right. I ordered the universal tool for pinion depth checking that requires a whole lot of figuring, subtracting blah blah blah so after receiving the tool i began to take it back apart.
I noticed also my backlash was too high now. The wear on the gears looked great. No gouging and shiny all the way across front to rear.
When I took it apart there was no depth number of this Ford 4.10 so I was like sheet! How am I supposed to check depth without a fooking number.

So I put it all back together but this time used the original wide shims for the carrier that came on the car. I had to tap them in with a hammer. It was a tight fit and I had very little backlash. Put it all back together and the whine is almost nil at that 50 to 40. I mean you reallllly have to try and listen for it. It may be due to it running like that for 100's of miles.

I think I am now happy with it. All in all the kit comes with misc shims. The problem is most are so thin you can't drive them in unless you stack them all together and it's still hard. I believe my issue was my carrier was too loose.

Just thought I would share my experience and perhaps it might help someone googling the same issue.

Thanks,

Austin V