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I have an 07' RRS SC and need to replace both diffs after getting it stuck in a swamp for an hour (rear has a clanking sound and wheel judders when turning at high angles), front diff is leaking. My mechanics opinion is they both should be replaced with remanufactured originals. I would love to turn this lemon of a situation into lemonade. I've been considering getting an ARB locking diff for the front for a while anyhow... is it possible to fit a rear elocker diff (one of the ones that would've been an HD add on)? It seems like the major snafu might be not having the right wiring on my harness already. I've tried looking at the related threads here but didn't find anything specifically confirming or denying.
 

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Discussion Starter #2
Also it seems like my options are dealer remanufactured for ($1400 front, $1600 rear non locking - they wouldn't quote me locking).
I'm also considering having mine rebuilt and having an ARB air locker added to one - $990 for locker - no word yet on cost. Is there a consensus on front vs rear in terms of best place to add an ARB? It seems like the rear should turn less in any given corner since it will track inward sooner.
 

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I talked to lucky 8 offload last week and its 2200 per diff shipped, assembled and ready to rip per diff. Not that bad if you ask me.
 

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I would be surprised if you developed diff issues sitting in swamp water for an hour or so - the diffs are sealed quite well and have extended breathers. What evidence (other than your mechanic's word) that the diffs are faulty. Was there water in the oil?

The symptoms you mentioned could be almost anything in the drive system, especially if the underneath has not been thoroughly cleaned to remove grit etc.

I would be getting a second opinion.

The OEM electronic rear diff has been retro fitted but is not a simple process.

Garry
 

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Discussion Starter #5
The symptoms are thus, I can see the rear wheels individually judder / skip when reversing or going forward while turning at or close to full lock. My front diff has a leak. My local junkyard has used ones (non locking) for $500 each. Stealership remanufactured were ~$1300 and ~$2100 for front and rear (non locking) plus a substantial core charge (1-2k I think). I can get the rear locking assembly for around $300 on ebay and an aftermarket motor for ~$200. My current thinking is the following... buy a rear locking diff and motor and try to reverse engineer the signal and manually fit my own switch in the cab. I had a LR engineer unofficially tell me it is just a PWM signal to control lock, the motor or locking diff control module could be reverse engineered (I have a bachelors in EE - so competent enough to figure out and or build an imitator). I've found the module for $50.

It seems like I can use the GAP tool to enable the locking diff in my computer - whether the module can be wired into my loom is the question I think - I need to figure out if it runs on the can bus or has its own special wiring from the TR module. I'll call the GAP guys and see if they know.

I am weighing flushing the front and either sealing in place with RTV or finding a replacement gasket (can I replace the gasket without pulling the whole diff? I'm such a noob in some ways).
 

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Discussion Starter #6
This is the most comprehensive info I've found on it.
https://expeditionportal.com/forum/threads/retrofitting-an-active-or-manual-rear-locking-differential-lr4.168031/

It seems like the custom control PWM route would be the way to go if I was going https://discoweb.org/index.php?threads/lr3-rear-diff-rebuild.93253/

Rebuilding the front/rear seem like painful options

https://www.rangerovers.net/threads/leaking-front-differential.41778/ - this and the SSM mentioned therein suggests that the front seal can go bad due to a bad breather that causes pressure buildup. In my case the breather was probably submerged when I got stuck. I'm wondering if a breather upgrade, flush and RTV seal hacking might be enough for my front.

Right now my head is spinning with options - I'm leaning toward flush and seal the front (if RTV isn't a no-no) and buy a used rear and have someone do it - no locker.
 

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Pirate and the portal forums may be OK but I dont know - do a search on either (not sure which one - probably the D3 one) https://www.rrsport.co.uk/forum/ or https://www.disco3.co.uk/forum/ as there is a full thread that covers everything required to retrofit the e-diff to the vehicle.

But then you can fit an ARB diff lock to both the front and rear of your vehicle.

As far as I am aware, the diffs have breather extensions as standard and these end up in the engine bay somewhere so unlikely a breather issue. However I am not so sure so you need to confirm elsewhere.

Garry
 
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