The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 64-65 rear axles

I never thought I could get in so much trouble trying to replace a 65 C-10 rear axle with one from a 64. We knew the rear in Deb's 65 was bad but figured we'd get to it later; it's later now! The one in it is a 3.73 posi but the posi is locked up like a spool. It slides the front tires turning out of the driveway or backing out of the garage. There were lots of metal pieces including some ring gear tooth tips inside. Her dad had a 64 on the hill so I carried it to the house with my front end loader. The 64 has a much different track bar mount, the axles are different splines and axle seals are hard to find. The ring gear has the same part number on it, so I guess they're the same. Are they both Chevy axles? The posi is an Eaton unit, I think.

There was a running change in the spline count on the axles in '65. For the most part, '63/'64 are 17 spline, like their '55-'62 HO33 predessor. The '65-'76 12 bolt is 30 spline, though I have heard of early '65 Truck 12 bolts wiht the earlier 17 spline axle.
As far seals, I'm not sure where you've checked, but Autozone has them listed for $20 apeice, part #84775, which is about the same price as the seals for the '55-'62 axle.

The 64 axle does have the 14 spline and the 65 has 30. That's another thing that worries me a little but since I'm going from a posi to open I guess it'll break loose before it breaks anything. We only have one small auto parts in town and he has to go through O'Reillys, they show having 2 seals in Springfield and they may be here today. If not I'll have to get Autozone at West Plains to order them. I had to cut off the big bracket for the panhard bar and order a relocation kit from CPP. I really thought it would be a simple bolt in when I started.

While I was messing around with this 64 axle, I forgot I have a 72 frame with the rear still in it. What kind of mess could I get into if I went with the 72 assembly on the 65? Will the axles interchange? I need to keep the 6 lugs. The 72 might also be geared higher and I wanted to keep the 3.73's since we have a 700R4 trans.

IIRC, the housing on the '67-'72 mounts the same as the '65/66. However, the '71/72 is about 2" wider than the earlier 6 lug axles, so the shafts do not interchange, or at least not going 5 lug to 6. I have heard of guys swapping the 5 lug axles into the 6 lug housing, after getting the shortened, to change to 5 lug.

OK, I got the 64 axle all mounted and hooked up in the 65. I decided since I was this far, I'd go ahead and replace the axle bearings too. I had to make a puller for them. The parts book shows them to be the same as 65-72 axles so they were in stock. The new bearing only has half as many rollers as the original and doesn't look near as stout. The parts guy even pointed that out. Now that I've got it all together, I can hear the axle going around the rollers in the new bearings on both sides. It may all be in my head but I think it's going to make noise when it rolls. It may be fine but I never heard anything like it. The axle didn't have a flat spot and didn't appear to be out of round.