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Rear diff strip down

Allchin

Active Member
Joined
Nov 16, 2010
Messages
67
Today, whilst waiting for other items to be delivered, I removed the rear diff. to inspect and replace the pinion seal.

We need to go back nearly 3 years......The truck threw the rear propshaft. at 60mph whilst driving down to the docks to ship the truck to America for our 2+ year trip, I ended up driving in front wheel drive into the container. Thinking I will buy a second hand prop and take it over the US in our bagage, then fit it over there. After getting the truck through the customs I brought it back to the motel to fit the propshaft, thats when I found oil weaping through a hairline crack in the casing of the transfer box later on I found that the pinion was bent!
We found a transfer box from a company in California($1500)+ $80 delivery + $300 swaping it out. The ring and pinion had to be replaced at $800 for a strip and rebuild. I had only done around a 1000miles on this new 410 ratio ring & pinion.

The moral to this part is do not skimp on inportant parts of the car. Normally I have bought UJ's from Milner and these are Toyo, 'Japanese spec' but made in China, I also saw and bought a pair on Ebay about £4 cheaper than Milners, but it turned out that I miss read the make, these were Toya! I had only done around 1000miles before a catastrofic collapse. From first hearing the noise to shedding the shaft was less than 30 seconds!

This diff was last rebuilt 85k miles ago in South Carolina, USA and upon inspection I found that the flange was out of true by 0.27mm, the spec. allows 0.10mm. Back lash was 0.26mm, from memory I think 0.20mm is the max.
After removing the pinion I found the shims for the solid spacer badly gouged, even one end of the solid spacer was also badly scoured additionally the oil 'slinger' was also gouged. I havent figured out, how this has come about, but I did re-assemble the pinion without the spacer and the flange offest was within spec!

Any ideas what caused it? I suspect it was due to too many shims used and the mechanic had to use imense torque to get the pre-load set.

Oil sling ordered from Toyota, next tuesday.... rear wheel bearings next...

Stephen
 

Dave 2000

Well-Known Member
Joined
Mar 26, 2010
Messages
2,743
Country Flag
spain
Minimal shims should be used to get the preload right. It is not uncommon to have a less than perfect shim pack 'give' as the load is applied, this allows the pack to 'walk' IIRC the max is two with a solid spacer, also seen poorly stamped oil slingers, eventually they flatten out and give rise to movement. And finally, the bearings on the ring gear could be wrong, this could make the ring/pinion contact incorrect.

Normally I farm these out, I lack the skill/practice to getting these right first time, although I did a couple of ARB lockers and these were ok, but take my limited knowledge as a guess.

regards

Dave
 
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