Differential bearing replacements

11/60 wrote: The axle case is definitely different between automatic transmission and later manual as my diff didn't fit when I had to replace my original axle case.

The front one? now you mention it I did have to grind a couple of mm off my 2007 axle case (the flange where the sealant goes) to get the 3.9 diff in on the front, back was fine.

Riccy wrote:

11/60 wrote: .... now you mention it I did have to grind a couple of mm off my 2007 axle case (the flange where the sealant goes) to get the 3.9 diff in on the front, back was fine.

So I guess that originally you had 1.3 VVT version with 4.3 diffs and you put 3.9 diff instead but you had to grind some mms. Is that correct?
But 3.9 is not the diesel version ...
I'd like to put diesel diffs (3.416) into petrol vvt 2005+ axles which orginalny are 4.3. Does anyone know if it is possible? Or maybe only change the crown wheels and shafts ?

correct, I did the 3.9 swap to gear up the diff as the rocklobster box is so low. The grinding was to the edge of the axle casing opening (top right) as the crown wheel was hitting and it wouldnt go in. only a tiny bit off to get it past and in.

putting a 3.4 diff in would make the car over geared and slow (depending on tyre size, gearbox and t-box combinations).

I cant help with the diesel diff question, not something ive ever seen in the UK. possibly a workshop manual would show the differences (if any).

Riccy wrote:
putting a 3.4 diff in would make the car over geared and slow (depending on tyre size, gearbox and t-box combinations).

I am planning to have rocklobster as well. So as I am aware rocklobster has 1,59 high and 4,16 low ratios. In that case, using 3,4 diff I would have to go with tires above 33" to make it overgeared. With 30" tires I will still have overall redution almost 10% on high and 31% on low comparing to not modified Jimny with stock tires.

Ah, that makes sense then. That sounds about right for the 30" tyres mentioned.

I run 31" on the 3.9 diffs with rocklobster and r7me gearbox. With the lobster and the 31's its just slightly over geared from a standard jimny, meaning 70mph its doing around 4000 rpm, a bit high but as i dont sit at 70 (often) its fine

The other side bonus of the combo i have is that if any part of it fails (and they are all the strongest of their type), the replacements are cheap and easy to get. The R72 gearbox mine came with was really expensive (£700+) to fix when it went, the r7me gearbox is about £150 to replace with another used one. Diffs likewise are easy to get and £160 bought me a pair.