Page 1 of 1
running with no front diff
Posted: Sun Apr 24, 2016 2:52 pm
by freddo
Hi everyone,
I recently procured a 2005 3.0d which has a shot front diff. The front drive and prop shafts have been taken out so its rear wheel drive only at the moment. It uses a 3.91 ratio which seems to be as rare as a very rare thing to come by. So my questions are:
Is it safe to run for the long term with rear wheel drive only?
Is it putting excess strain on the rear diff? The original power split is 30/70 (I think), so I'm assuming 100% power is going to the back.
Would it be lighter on fuel being RWD?
Re: running with no front diff
Posted: Sun Apr 24, 2016 3:08 pm
by X5Sport
Hmm, that's different.
What's happened to the drive unit? That splits power front rear so if it's still enabled and you get slip at the back, what happens?
Longevity of the system, probably not the best.
If the drive transfer box (xdrive) has been disabled in an 'all rear' setting then you are RWD only.
Any warning lights?
Does your insurer know? They need to.
Probably won't make a massive difference to fuel.
Different are very hard to come by, except from either a scrap car or new from a BMW Dealer, the latter being very expensive! Have you got the front drive shafts? Does the suspension/steering not actually need them to be in place (I don't know if their presence or not is significant)?
Re: running with no front diff
Posted: Sun Apr 24, 2016 5:03 pm
by freddo
Xdrive must be disabled, there are no warning lights.
There are no drive shafts, looks like the front diff suffered a catastrophic failure, there's a hole in the casing where something shot through!

) but absence of the shafts hasn't affected steering or suspension.
The 3.91 ratio seem particularly rare and stealers are way too expensive
Re: running with no front diff
Posted: Sun Apr 24, 2016 6:11 pm
by X5Sport
Well it's working so will probably go on for a while. At least you won't have to worry about the tyre issues that have to be at least considered by the rest of us.
kkx5 is the man who will know for sure

Re: running with no front diff
Posted: Sun Apr 24, 2016 7:11 pm
by kkx5
[quote="freddo"]
Xdrive must be disabled, there are no warning lights.
There are no drive shafts, looks like the front diff suffered a catastrophic failure, there's a hole in the casing where something shot through!

) but absence of the shafts hasn't affected steering or suspension.
The 3.91 ratio seem particularly rare and stealers are way too expensive
[/quote]
No lights: xdrive enabled, abs enabled, dsc enabled. No propt shaft: running into potential accident when system will want to switch the power to the front and will lock rear wheels...
Re: running with no front diff
Posted: Mon Apr 25, 2016 8:32 pm
by freddo
Thanks for the input gents, will have the tech look at it this week.
I read somewhere that the Xdrive can be disabled by unplugging a cable found under the passenger orrear seat. Is this true?
Re: running with no front diff
Posted: Mon Apr 25, 2016 9:38 pm
by kkx5
Until you get it sorted, Remove fuse no 46 (transfer box/xdrive). Its better to drive with systems off than driving with systems on but no shaft.
Re: running with no front diff
Posted: Tue Apr 26, 2016 6:11 pm
by freddo
Thanks for the heads up, fuse 46 (transfer case) removed.
Don't BMW supply a fuse removal tool, was tough getting it out

Re: running with no front diff
Posted: Wed Apr 27, 2016 5:51 pm
by X5Sport
That'll be £150 + fitting (at least an hour) + VAT sir..........