Front diff again

john.briggs · Post by **john.briggs** » Mon Nov 26, 2007 11:43 am

Earlier this year I had to replace the front diff on my '96 SGLR when the whining noise finally became more than I could bear. I replaced it with another one from a broken Bongo which included a 30-day warranty. 10 months and about 7000 miles later problems have started again. This time it's not so much a whine but a rumble at low speeds up to 30 and then more even bearing noise up to 60. The o/s front tyre also seems to be making slapping noisesas it goes round. I've taken the vehicle to 2 garages for inspection, one a Bongo-friendly in south Wales and the other my local one who replaced the diff 10 months ago. Both say it's the front diff again. Rather than get another used one, I'm wondering if it's possible to rebuild the one I've got and if so, where. Has anyone gone down this road before? I've been quoted 800 quid for a new diff from Mazda which I really don't want to spend on such an expensive Christmas present for the Bongo, much as I love/hate the darn thing. Would be grateful for any help/advice/sympathy.

bigdaddycain · Post by **bigdaddycain** » Mon Nov 26, 2007 12:14 pm

I can't offer any advice on the rebuild, but perhaps waycar has his front diff left? (i cant remember if he's 4wd off the top of my head)

Wayne is top man for very budget prices for bongo bits at the mo...

Ralph · Post by **Ralph** » Mon Nov 26, 2007 1:10 pm

Rebuilding diffs is a black art even the experts end up
with noisy ones, if you have two spare wheels try swapping
them for the fronts or the same size all round try swapping
front to rear.

smartmonkey · Post by **smartmonkey** » Mon Nov 26, 2007 1:31 pm

If you still have the old one I would look to rebuild that. If the teeth on the crown wheel and pinion are OK then its just a matter of shims and bearings. The high pitched noise the old one made suggests it may just be the bearings. The bearings can come from any factor at reasonable prices. The only tricky bit is setting up the pinion endfloat but it's not that hard.

If the teeth are worn then the price will mount up because you will probably have to get them from mazda.

dandywarhol · Post by **dandywarhol** » Mon Nov 26, 2007 3:53 pm

I'd be looking into the cause rather than the solution - sounds like a viscous coupling problem causing the diff(s) to fail.

mikeonb4c · Post by **mikeonb4c** » Mon Nov 26, 2007 5:49 pm

As Dandy implies, it is is curious. Was it BF member Harry who's well travelled and v reliable Bongo 4W Bongo has nevertheless chewed up (at least) 2 diffs. in a relatively short period of time. Maybe PM him to see if he has gathered any clues as to cause?

missfixit70 · Post by **missfixit70** » Mon Nov 26, 2007 6:19 pm

Not being an expert or anything, but it's not down to incorrect tyre sizes & the wind up effect on a 4wd is it?

waycar8 · Post by **waycar8** » Mon Nov 26, 2007 6:29 pm

yes mine is 4wd BDC, (ps you make me sound like a dealer or sumat

)

mikeonb4c · Post by **mikeonb4c** » Mon Nov 26, 2007 6:32 pm

Tell you what Wayne - watching your old Bongo get stripped makes me think we should rebrand ourselve as Piranha Fish Fury

dandywarhol · Post by **dandywarhol** » Mon Nov 26, 2007 7:50 pm

missfixit70 wrote:Not being an expert or anything, but it's not down to incorrect tyre sizes & the wind up effect on a 4wd is it?

You're right Kirsty - that can cause it if it's outwith the recommended spec (whatever that is

)

Mikey B · Post by **Mikey B** » Mon Nov 26, 2007 8:16 pm

Last year I broke the front diff on my 4WD Bongo when I first bought it.

To cut a long story short it was to do with different size tyres, front were road tyres, rear were snow tyres, this is how it came over from Japan apparently.
These had a different rolling radius and caused a whirring noise from the front end. It also caused to autobox to get hot and there was a smell of hydraulic fluid.
Had the front diff changed by a garage in Gorseinon, no problem since. Replacement diff has been on the Bongo since Oct 06 (13 months ago).

smartmonkey · Post by **smartmonkey** » Tue Nov 27, 2007 1:41 pm

If it was a new diff that had failed it would be a valid point but with a secondhand one who knows how good it was before? Diffs usually fail because of oil problems (not enough, wrong grade, too old etc.).

bigdaddycain · Post by **bigdaddycain** » Tue Nov 27, 2007 1:46 pm

missfixit70 wrote:Not being an expert or anything, but it's not down to incorrect tyre sizes & the wind up effect on a 4wd is it?

I think dandy could confirm that mismatched tyres and a 4wd bongo would need to travel on an old roman road in an arrow straight line for quite a few miles for the diff to become slack enough for them to wind up again...That's if my limited (slip diff

) knowledge has got the concept correct.

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