3:55 r&p swap. Just disassembled the pinion gear. All info says it is supposed to be torqued at 200-240 ft/lbs then peened over at the shaft slot. It was peened but I removed it by hand. Assuming someone at sometime was in the diff and didn’t assemble correctly. No way it could have loosened and been peened over. When I unpeened the nut it broke the flap that was peened over. Nut is still usable. Appears to be brass. Question is should I/ can I just rotate the nut when torquing and peen it at a new spot. Or should I replace it? No parts numbers in the shop manuals and doesn’t appear to be available at the bigger parts suppliers. Has anyone gotten a new one and where from? Thanks in advance.
Last edited by bigedpa; 02/16/202512:52 AM.
"it's only old if you can't find a use for it; otherwise it's cool and i'll use it."
I just swap to the 3:55 gears a few months ago and my pinion nut was not very tight - no way was it torqued to 200-240lbs. When I reinstalled the nut, I tightened it and it went past the peened area, so I figured it was tighter than before and peened it at the new location.
~ John in Utah 1946 1/2Ton w/4-speed manual transmission w/1960 235 engine Here We Go Follow in his DITY Bay
- If you think about it, it has been one year ago today!
There are pinion nuts available on eBay. Link Also available from The Filling Station. Link
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Kl. Thanks. Didn't think of eBay. Had looked on filling station with no luck. Must be search terms I used.
Utah. first thought was to put it back the way I found it. Truck has never run so I’m not sure if it operated that way. Is yours up and running as should without applying the tourque spec?
"it's only old if you can't find a use for it; otherwise it's cool and i'll use it."
Not running yet. I hope it doesn't come back to bite me. I drove this truck 20 years ago with no issues. I know I didn't torque it to 200+lbs, but I did tighten it pretty good - I mean a lot tighter than it was.
~ John in Utah 1946 1/2Ton w/4-speed manual transmission w/1960 235 engine Here We Go Follow in his DITY Bay
- If you think about it, it has been one year ago today!
Got my eBay pinion nuts the other day. Original gm parts in the original box. These are steel and not brass like the current broken one. Question is the peening process. My thought is to torque the nut down. Mark the location of the peen slot in the pinion. Remove and cut a slot the collar of the nut. Then reinstall and peen it over. Anyone have a different thought or process? Thanks.
Last edited by bigedpa; 02/25/20251:50 AM.
"it's only old if you can't find a use for it; otherwise it's cool and i'll use it."
Just torque the nut down and use a punch or chisel to peen the edge of the nut into the slot. There's no need for a cut in the nut, as long as you get a few thousandths depression into the slot.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
