Pinion pre-load during differential setup (1 Viewer)

[lacalvette]

Well reading the pub 36262E printed in 1994 (the one that I normally use)
Repair manual chassis & body
The mention (at starting) is not there anymore and preload are not the same!
Pinion (new bearing)alone is 1.9-2.5 N-m
Total preload (in addition to pinion) .4-.6 N-m
So 2.3-3.1 N-m
That kind of odd no?

 

[Eurasiaoverland]

Well reading the pub 36262E printed in 1994 (the one that I normally use)
Repair manual chassis & body
The mention (at starting) is not there anymore and preload are not the same!
Pinion (new bearing)alone is 1.9-2.5 N-m
Total preload (in addition to pinion) .4-.6 N-m
So 2.3-3.1 N-m
That kind of odd no?

View attachment 3214162

Strange indeed. I think these FSMs are not particularly well put together and I have started looking at various versions to try to piece together the full story.

After you mentioned continuous vs. break-away torque, it seems that it is usually measured as continuous turning torque. Also, in my FSM it does not mention which measurement is referred to.

Lots of room for error here! I will aim for around 2.5 Nm continuous turning torque (all bearings are new) as I would rather have the bearings a bit tight than a bit loose (it's cheaper to replace bearing vs. replacing the things they spin on (pinion shaft and diff carrier) if the preload backs off!

 

[lacalvette]

In the same FSM, rear axle RA-20 under Inspection of differential. (Check)

It says preload (at starting) .9-1.3 N-m
Then total preload (while turning)
Add preload (at starting) .4-.6 N-m

In that case they probably refer measuring the pinion preload within the gear backlash (pinion and ring) in order to measure only the pinion (so the ring gear does not turn).

While turning mean the measure take all bearing in accounts

 

[Eurasiaoverland]

Just to close this out, I put a bit of box section over a breaker bar with the 30 mm socket and crushed the sleeve. I was expecting the $20 Chinese breaker bar to come apart but it was impervious to the 250-300 odd Nm I put on it. I've ended up with about 3.0 Nm preload at the flange - if the numbers in the FSM I have (1.9 - 2.5 Nm for a new bearing) mean total pre-load at the flange then I've gone a bit too far, but if they should be subject to addition of the carrier bearing preload (0.4 - 0.6 Nm) then I should be aiming at 2.5 - 3.1 Nm and I'm right in that range.

The vehicle had been run for a long time it seems with no preload on any of the rear diff bearings (the one I just rebuilt is the front) - one of the carrier bearings had spun on the carrier journal and was loose, the outer pinion bearing was worn from spinning, the bearing journal on the pinion shaft was worn and, worst of all, the splines on the pinion shaft were severely worn with the flange splines alomost worn flat.

I suspect that the turning torque at the flange is a bit tight, but at the end of the day, bearings are cheap. Diff carriers are not, and getting a new, genuine ring and pinion for a 60 series is extremely expensive and involves upgrading a lot of the associated hardware (both bearings, different spacer, new flange, oil slinger, nut and yet another oil seal from the one that is supplied with the set). So I would say I'm happy with where I am!

Thanks for all the input,

EO