Posted by Dave austin on Monday, February 28, 2005 at 9:23AM :
I did a swap out of my 1/2 ton rear diff with that from a 3/4 ton rebuilt unit with 4:89 gears.
I bought all the neccessary peices, including the three 1/16" gaskets for proper spacing and alignment of this diff and the 3/4 ton axle shafts into the 1/2 ton housing
I took out the old (original) 1/2 ton diff with 8-5/8" R&P, removed the 3/8" studs and replaced with the proper necked down 3/8" to 7/16" studs.
I grinded a small area top and bottom along the housing opening and easily installed and tightened down the newly rebuilt 3/4 ton rear diff int othe 1/2 ton housing... Easy enough.. All went as planned. All good so far. No surprises.
Next, I install the rear axle shaft. Drivers side first, slid right on in and bolts right up snug.
However, the passenger side rear shaft goes in ok, but when it starts getting close to seating, i.e. tightening the bolts, I can feel pressure. Obviuos binding inside..
I have used the correct metal seals on both sides with liberal amounts of RTV.
I snug up both sides but am aprehensive about that really tight feel on the passenger side.
I jack up the truck, both wheels off the ground, no driveshaft on at this point, and try rotating the tires. TOO TIGHT!!! wont turn!
I back of the screws on the passenger side
shaft, and I can feel it release the pressure.. Now it turns easily. I got about a 1/16" inch gap r possibly more and it works nicely, rotates smoothly..
So, whats happening? are the 3/4 ton shafts too long?
I took them out of a working 3/4 ton truck???? Didnt see any reason they shouldnt work then, or now.
Are there supposed to be a stack of paper gaskets that will take up this space that I didnt install (Never did before on any other trucks, just used RTV silicone)?
Anyone got ideas?
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