Evening all,

Being the silly I am I'm off on a laning trip of the UK. Just finished Strata Florida and it sounds / feels like the rear diff has locked up. It does not have the locking rear diff.

Symptoms are on applying some lock the inside wheel starts slipping and there is a slight knock. Gets worse on tighter locks. I have been through some reasonably deepish water (within the limits of the vehicle) today so there may well be some moisture in an ECU somewhere.

Does anyone have any ideas on what might be the cause? Got back in the dark so haven't had a decent look underneath but have most necessary tools (and am an electronic engineer so not afraid of a soldering iron - and we have one).

I have an IID tool (cleared all faults - nothing of relevance) which didn't help and also the workshop manual but after three days laning after two months of hectic work I'm pooped so heading to bed soon...

(Will provide some tasty footage when I get a chance as well).

Cheers Ed

Quick check would be to jack both rear wheels up with the handbrake off. Spin one wheel, and the opposite side should spin the other way. If it does then the rear diff is working as it should. If it doesn't then there is a problem with the diff.

( Not sure if there is a locking diff on the rear of a tdv8 ) V8 or else ...

the diff on the rear of the standard 3.6 is an open diff, there is an optional electronically locking option which works via a clutch pack built into the diff but this was rarely specified.

the latter can be identified by looking at the diff, if you have a actuator motor bolted to the front of the diff, then you have the locking type, if you don't you have the open type. If the open diff is locking then something has gone seriously wrong inside, and I'm pretty sure that you would have notices some bearing noise etc first.

Have a look and see what type you have. If you have the locking type then it maybe that some water has gotten into the wiring and caused it to malfunction. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Thanks fisha - very sensible suggestion - shows how little my brain is working at the moment.

Will definitely try that in the morning. There isn't the actuator on the top so it's not a locking diff but from what I can work out from the manual it should be an open diff with any locking motion coming from the Terrain Response. Ed

^yep thats how it works, applies the brakes to the slipping wheel and directs torque to the wheel with the grip.  There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Ed,

Sounds very much to me like a problem with an ABS wheel sensor, when it does it are you getting a similar noise but quieter that the HDC makes... I had problems with water ingress into one of mine that was a pattern one, it didn't throw any faults just kept trying to lock one rear wheel..... I changed it for a genuine one and it has been fine since but water in the connector that is tucked up behind the wheel arch liner will cause problems. Not sure which fuse it is on yours but pull the one that does the ABS and see if it's any better.....

Unless you got water inside the FF you won't have got any ECU's wet enough to do any damage... mine regulary wades at over twice the recommended 500mm with no adverse effect...

I hear Strata is a bit empty at the moment....?? Pete
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Last edited by Haylands on 18th Oct 2015 8:17pm. Edited 1 time in total

Be prepared for less and less coherent messages - currently sat in a pub...

Current plan is to give it a quick try tomorrow morning - if it's a moisture issue and it's magically fixed itself tomorrow (I have stopped and started the car a few times as well as changing the various terrain response modes - although thinking about it I haven't tried going into low and back to high again. I was in low and then came into high but not gone back yet) then I'd still like to know where the problem lies.

If the issue hasn't disappeared then I'll put it up on axle stands (conveniently have a pair of them in the car ) and check the operation of the rear diff. Note - there's no sound of bearings or anything broken from what we can hear - just this scrubbing but then a clunk and the wheel slips which sounds like transmission wind up.

If worst comes to the worst I'm not far from my parents (we stayed there last night) and I can arrange a mate with a trailer / RAC to get me down there to have a decent look with the pitt.

I suspect I'll head off to bed soon but if anyone does have any ideas then please post them. I'm leaning more towards the centre diff causing issues rather than the rear - but we'll see.


Cheers for the rapid responses though guys. Ed

Very much doubt it's a diff they either work or they don't if they don't it won't go anywhere........  Pete
I now have permission from the boss to use Y.O.L.O. Enjoy life
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
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-Click for Project Fatty off roader-

Cheers Pete - was wondering how long it would take you to chip in.

Yes Strata is currently a bit empty - the river bits. We've done it from Soar y Mynydd end and just where you exit to the large open area half-way along had the deepest water. Was about as deep as I'd be comfortable going without my snorkel idea. I have the issue it comes out the left wing which is the wrong side for a D3/4 one.

Might be tempted to pilfer the 3D printers at work to print one...

I shall try pulling the fuse for the ABS as well tomorrow - cheers for the suggestion. Doesn't sound quite like the HDC as it's more like a mechanical clunk from the rear end but some of the guys were outside the vehicle and noticed the inside wheel slipping.

Hopefully won't be something too bad - I only noticed it come off the tail end of Strata at Tregaron end I we emerged onto the road. Ed

yeah, the noise was like the HDC but it thunked....!!! a bit more positive and mechanical sounding.... darn difficult to describe a noise....!!!!!! Pete
I now have permission from the boss to use Y.O.L.O. Enjoy life
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
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Sounds (sorry no pun intended but I'm waiting for 20GB of footage to copy onto the laptop so slowly working through the pints) like it might be an ABS sensor if yours did sound more mechanical as I would definitely describe mine as mechanical.

On a plus note - three days in and I haven't written off any more tyres yet... Definitely prefer the Wranglers to the Grabbers. It is nice being in an FF though.

Got a P38 with Joe Sardo (apparently he might have spoken to you before Pete), Pajero, Jeep, 200Tdi 90 and my FF. Definitely got the comfort sorted. Ed

Name rings a bell, say hello to Joe for me...

Weird, I defo prefer the Grabbers to the Wranglers which seemed to be made of cheese to me... had the Grabbers on for over a year and they are still fine... the Wranglers didn't even last one trip to the lakes, Grabbers have done three trips already....

Have fun with the rest of it, hope you sort the rear out OK....  Pete
I now have permission from the boss to use Y.O.L.O. Enjoy life
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Funnily enough I've had the opposite. Wrote off two in the lakes (Grabber ATs) and then another one in Surrey. Sidewalls seem to be mush in 255/55R19. Found the Wrangler Duratracs to have much better tread pattern and (holding on hard to the sideboard here) have survived Sarn Helen, Brechfa, more Brechfa and Strata over the last three days. Plus some other random stuff in between.

Will tell Joe. They're actually heading to the Lakes (I'm skipping off to visit grandparents but might join them again in Cape Wrath). If you fancy a jolly... Would be good to actually meet up at some point. Ed

If the centre diff is locked then the rear inside wheel is the most likely to spin when turning to relieve front-rear wind-up .

Well slight update.

Rear diff is fine.

Pulled the smaller of two fuses for ABS and HDC and that threw up a load of faults when unplugged but didn't fix it. Now got permanent HDC and ABS disabled faults that won't clear. Tried battery disconnect as well.

I've jumped in with someone else today who was leaving tomorrow so we'll head to my parents, stay the night and I'll return with the 110 and a trailer to get the RR back to the farm and have a proper look in the barn. Ed