[BigChassis]

I have just acquired a SJ80 Sierra, 02/96, G13BA motor, 5 speed, 4WD, Coils all round, Chassis no. JSAOSJ80000100152. It seems to be a rare beast in that it has a solid front axle with a Vitara Diff (4.625:1 Ratio). Some one swapped the rear diff out and put a 3.909 ratio in it. So no 4WD. I have been informed (not sure how accurate) that Suzuki did a short run of these vehicles with Vitara Diffs. Does anyone know anything about this? And where can I find a 4.625 diff for the rear?

[Brenno]

Doesn't sound right to me.

Have you confirmed the front diff ratio by checking how many times the pinion turns to spins of the wheel?

I believe factory ratio is 3.9 so the rear is likely standard.

What happens when you put it in 4wd?

[BigChassis]

Yes, Have counted the gears. I believe the previous owner sent the rear diff (4.625) away to be repaired and the diff man looked at what he thought was the correct ratio (3.9) and altered it to that. But it is wrong for this car. I still need a 4.625 diff for the rear. Thanks for the comment.

[Gwagensteve]

A) No. There were no SJ80 Sierras fitted with vitara diffs.
B) All SJ80 Sierras are solid front axle.
C) All SJ80 Sierras have 3.9 diff ratios. There are no alternative ratios.

That's the facts.

Now to the speculation.

SJ80 (and Jimny) front diffs are "high pinion" - the pinion sits above the axle centreline. Suzuki used this design because when used in the front a high pinion design is stronger when driving forwards, and the high pinion provided enough room for the tie rod to fit between the pinion and the radius arms.

SJ80 front diff gears/centre/housing are very hard to find.

Vitara front diffs use an alloy housing that's very slender around the pinion. The diff is still "low pinion" but if the viara alloy housing was used, there might just be room to sneak the tie rod below it. so maybe the mechanic found something that sort-of fitted and threw it in to fill in the hole.

The only other explanation would require lots of custom fabrication and parts to fit a low pinion, steel Sierra diff housing with a low pinion 4.625 ratio in the front.

A couple of photographs would clear this up.

[Gwagensteve]

To add, if you have an alloy front diff housing ("third member") that's been installed to clear the tie rod it will fail, they are not designed for that application.

Best solution would be to replace the front diff with a 3.9 high pinion SJ80 diff. 4.6 will also be far too low for an SJ80 unless it has quite large tyres.

[Gwagensteve]

So what was the outcome BigChassis? What parts do you have?