Series Diff Overhaul

**gromit** · 15th May 2013, 02:51 PM

I have a spare diff I thought I'd overhaul for 'stock'. I knew the outer pinion shaft bearing was rusted but I thought I'd be able to salvage the rest.

Stripped it last night and all the bearings are badly damaged due to rust (there was a rust hole in the diff cover) but the crownwheel & pinion are OK.
Timken crownwheel taper rollers $16 for the outer race $25 for the inner race.
Timken inner pinion shaft bearing $33 for the outer race and $45 for the inner race.
I already have a Timken outer pinion shaft bearing.
So $145 for the other 3 bearings....... almost cheaper to buy a 'parts car' and hope that one of the diffs is OK.

I may proceed with no-name bearings.
I'm hoping to measure the height of the old inner pinion shaft bearing and compare with the new one. I can then measure the shim fitted and add or subtract the difference in the bearing height of the replacement bearing and re-shim.
Any thoughts on this ?
It does assume that it was set correctly to start with plus I'd 'blue' the gears and check afterwards anyway.

Colin

**Blknight.aus** · 15th May 2013, 03:21 PM

if you want to go that way I've probably got a couple of series diffs that are going to come up as spares.

PM me if you want an option to buy once I start stripping the diff housings down.

**gromit** · 16th May 2013, 06:35 AM

Originally Posted by Blknight.aus

if you want to go that way I've probably got a couple of series diffs that are going to come up as spares.

PM me if you want an option to buy once I start stripping the diff housings down.

Thanks Dave.

I'm onto a S2 LWB parts vehicle, just have to get it past SWMBO.

Went to view it a few weeks ago, opened the tailgate and the hinges ripped out of the rear crossmember. Front wing damaged where a branch has dropped on it.
Lots of usable parts (tub, 1 wing, cab, motor, gearbox etc.), hopefully it has a usable diff.

I'll see if he'll let me part it out where it is, if not I need to negotiate with SWMBO.

Colin

**isuzurover** · 16th May 2013, 07:02 AM

If you go down the rebuild route, check the thread on the pinion carefully and don't overtighten the pinion nut. I have seen a few diffs fail that way.

**gromit** · 18th May 2013, 08:43 AM

The diff I have from a Series III has '49T75' stamped on the outside edge it's 4.7:1 ratio.
Another diff I was given has '19T73' stamped on the outside edge, it's 3.54:1 ratio.

Do the numbers on the diff give the build date ?

I've decided to get some no-name bearings and re-assemble the 4.7:1 diff. Never done one before but doesn't look difficult. I'll dust off my magnetic dial gauge base & dial gauge for checking the backlash and find a spring balance for checking the pre-load.

Toyota Tundra diff rebuild on YouTube
[ame=http://www.youtube.com/watch?v=dAqAqODmcj4]Differential Ring and Pinion Gear Setup - YouTube[/ame]
I love the diff holding fixture, difficult to justify for a one-off though.
The Toyota has a pre-load on the crownwheel bearings (in the Land Rover manual it just states 'zero endfloat'). Interesting how the guy measures the crownwheel bearing pre-load from the pinion end.

Colin

**gromit** · 25th May 2013, 09:21 AM

I've started the diff overhaul. Pictures here http://www.aulro.com/afvb/showthread...46#post1917746 post #173

Colin

**Sitec** · 25th May 2013, 09:46 AM

Have two SWB's both with 4.7's in them if you get stuck. Will be running 3.54's.

**gromit** · 25th May 2013, 03:54 PM

Originally Posted by Sitec

Have two SWB's both with 4.7's in them if you get stuck. Will be running 3.54's.

Thanks but this is just a spare. I still have another complete spare axle to check out and a spares car to collect (could be 2 more diff centres that are OK).

Just wanted to be in the position of having one that is a known quantity.

Colin

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