Mitsubishi Shogun diff issues and replacement

[Walter Sobchak]

Posting for a friend, they’ve got a 2004 Shogun and the rear diff is whining and feels a bit juddery so looking to replace with a second hand one off eBay, the one on it at the moment is a 3.917 ratio and we’re assuming lsd as it doesn’t have the rear diff lock.
There are other diffs available but the ones with a 3.917 ratio are lockable, and there isn’t a button for this in the car, there are also ones with a 4.100 ratio available.
Would it be ok to put one of these on it?, or would it need to be the exact same as the one there at the moment?, the size and connections etc appear to be the same it’s just the locker which he’s not too bothered about using, is this likely to interfere with the traction control if it’s not locked?.
Thanks in advance for any help.

[GreenV8S]

If it's four wheel drive, you should not change the rear diff ratio unless you understand what effect this will have on the rest of the transmission. For example, if it has a center diff this would be forced to work a lot more than normal if the front/rear diff ratios are mismatched and would see a lot more heat and wear. Presumably the speedo would read inaccurately. If you have traction control, ABS or anything else dependent on differential wheel speed, I would expect that to get upset too.

[Walter Sobchak]

Thanks, it’s 4x4 with centre diff and high/low ratio, would it be ok to put another diff in that is the same ratio but has a diff lock(it was an option on them) if he’s not bothered about actually locking the diff.