Diff Pinion Preload

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June J
Technician 3rd Grade
Technician 3rd Grade
Posts: 382
Joined: Fri Jun 18, 2010 4:27 am
My garage: 1942 Dodge WC 53
1941 Willys MB
1960 M38A1 Nekaf
Location: New Zealand

Diff Pinion Preload

Post by June J »

I am rebuilding the front differential on my WC 53. This has had 4.89 : 1 ring gear and pinion sets fitted.
I note that the oil slinger for the front pinion bearing is missing, as is the oil baffle for the rear pinion bearing. When I assemble the pinion into the carrier with the bearings, preload spacer and the pinion to input yoke washer and tighten the nut I have approximately 0.025" pinion end float, rather than preload. The bearing spacer is the smallest size @ 0.179"

When I inspect the pinion yoke (companion flange) nut and washer, I note that the pinion splines are approx 1/8" (0.125") below the washer rebate in the pinion yoke so its not bottoming out there. I am wondering if the combined thickness of the (missing) oil baffle and oil slinger is causing the yoke to bottom out on the spline adjacent to the outer bearing?

Ant thoughts appreciated.
Cheers
Ian
1942 Dodge WC 53
1941 Willys MB
1960 M-38A1 Nekaf
motto
Technical Sergeant
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Posts: 1037
Joined: Sat Apr 17, 2010 2:25 am
My garage: Harley Davidson 42WLA, Dodge WC63, Dodge WC57, Chevrolet 1-1/2 ton 4x4. Originally an Earth Borer, Pole Setter. Drilling rig gone and truck now mounts a #7 Set Lifting Frame. i.e.: Light Wrecker.
Location: 70km from Melbourne Australia

Re: Diff Pinion Preload

Post by motto »

I have recently rebuilt a second 9-5/8"diff with 4.89 : 1 crown-wheel and pinion set for my M37 and have become a little bit familiar with them but you're playing with an 8-3/4" by the sound of it which is a completely different beast.
Having said that, it would seem a forlorn hope to get your preload correct with one possibly two items missing that will affect the final positioning of the bearings in relation to each other.

Dave
June J
Technician 3rd Grade
Technician 3rd Grade
Posts: 382
Joined: Fri Jun 18, 2010 4:27 am
My garage: 1942 Dodge WC 53
1941 Willys MB
1960 M38A1 Nekaf
Location: New Zealand

Re: Diff Pinion Preload

Post by June J »

HI Dave,
I did some measuring yesterday and found that it was in fact the bearing preload spacer that was preventing the drive end cone from seating into the cup. Using a dial gauge I was able to ascertain that the spacer needed to be reduced by 0.027" to give me 0.001" preload. The diff is back together pending the arrival of a pinion seal and hopefully I can find a slinger locally.

Cheers

Ian
1942 Dodge WC 53
1941 Willys MB
1960 M-38A1 Nekaf
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