Does this diff need replacing?

[deanbayley]

I have had the diff out and i'm not sure how bad it is, in the 6 years as a mechanic / MOT tester i've never had cause to take a diff apart as 95% of vehicles we see are front wheel drive..

Please can anyone in the know have a look at these videos and tell me your opinion..

Back of Diff https://www.youtube.com/watch?v=FiDzzKr2UvI

Inside of Diff: https://www.youtube.com/watch?v=kZcO0LLvG0w

Dean.

[Darrell]

I would say that's bad , but it's hopefully rebuild-able ??
Looking at the oil it's got water in it.
It will need a strip down and good degrease to see what condition things are in.
The bearings are quite dear though.
I will admit I've never changed bearings in a diff as the repair manual scares me and shows too many
special tools

[Ladaman]

I wouldn't bother repairing that. It looks to have had lots of water in it. The pinion bearings are shot, possibly the wheel line bearings too.

If it has been running like that for a while, the contact on the gears will be worn, and there is nothing you can really do about that now.

If you knew the history, and it has just gone, it maybe a repairer. But looking at the prop, and how long that must have been knackered, I'd bin it. Or keep as spares for a diff carrier, housing etc...

Count the numbers of teeth, and ask on here for a replacement diff. I'm sure there will be something lying about. I know I have some Samurai diff gears, but you will get a diff cheaper than rebuilding that.

[deanbayley]

Are the front and rear diff's interchangeable?

What i was thinking is i could change the bearings and swap the front and rear as it'll be 90% road car for work and back (few miles a day) and 10% off road toy..

I can keep a close eye on it..

Obviously depends how much i can get another diff for..

[twiss]

Front and rears are not interchangeable unless you take them apart and swap the side gears...
In which case you might as well just take it apart and rebuild it...

[ScottieJ]

Those pinion bearings have been gone for a while for there to be that much play. You can swap a front to rear, however you need to swap the side gears from the rear diff into the diff. Rears are 26 spine and fronts are 22spline. This will involve setting up the backlash and bearing preload. You need to measure these before stripping and reset to those specs on a used diff.

I actually prefer to buy front diffs to swap rear side gears into as the fronts hardly see any use if free wheeling bubs are fitted.

I'm not sure if I would rebuild that one. Maybe give it a good clean to inspect the ring and pinion for abnormal wear.

[Ladaman]

I thought they were, but obviously wrong. I didn't think about the side gears

Getting the front one out is more of a pain to do than the rear, but you can't run with a diff missing if that is what you was considering.

I suppose you could if essential, but the front drive shafts would need removing, and the diff hole in the casing blanking off.

Just hang about for someone to offer you a new diff. It generally isn't long.

[twiss]

I think getting the front out is easier as you can to it all with an adjustable spanner lol.... don't even need a hammer!!!
and scottie shut up before you start with your full floating

[Ladaman]

I think getting the front out is easier as you can to it all with an adjustable spanner lol.... don't even need a hammer!!!
and scottie shut up before you start with your full floating

Don't all SJ's have full floating?

[ScottieJ]

All good SJs do Full float converted rear axles make it super easy to pull the diff....don't even need to take the wheels off 20 bolts and its out.

But yes technically the front is a floater too.

Wouldn't actually be an issue to run around with no shafts or diff in the front axle. But as Ladaman says it would make sense to blank off the axle where the diff goes to keep crap out of it.