That recommendation must have changed for 2021, no mention of using 75/140 for the Rubicons in my manual. Actually, no mention of a different fluid for towing at all in my manual.
I thought Royal Purple didn't need any additive?Did mine today, 11k miles, rear was jet black but front wasn’t bad at all, no metal on the drain plug magnets but a tiny bit of of grey sludge was there. Overall very easy to do, used Royal Purple 75w-140 in the rear and then finished the bottle in the front before topping off with 75w-90. After adding the additive in the rear I used less than 3 1qt bottles total.
It probably doesn't hurt to add a couple of ounces of the Mopar LSD additive, especially with the number of D44 LSD knocking issues reported on the forum. Also, unless I'm interpreting gear oil specs wrong, most meet the MS-5630 LSD additive requirement, but very few meet Mopar's MS-10111.
Probably overkill, better safe than sorry.
But everything I've found so far indicates too much limited slip additive is a bad thing, causes LSD to operate as an open differential. Personally I'm going to change mine with Valvoline 75W90 that has the additive already in it and check it for chatter. If it does then I'll add a little at a time until the chatter goes away. I bought my particular JL because it had an LSD, I don't want to end up losing it.
Correct, too much additive can cause issues just as not using additive can cause issues.
Unless you are using 4 wheel drive a lot you will usually see / know that the front is not necessarily in need of a fluid change whereas the rear, working all the time, will definitely need .... but probably most, will say DO, change both when you do the deed.
yep your right might as well....thanks for the input....18 with only 10k.....
Same here, US model
@21RubiconZ
I will use the 75/140 if I should, just annoyed the manual isn't more clear
