TheTank

Hey guy's just installed 5.38's on my jk. I got about a 1000 miles on the new gears since the install. Everything seems to be working fine, I was just wondering if I should take it back to the shop to have them check on the breaking-in process. Just to be sure, but don't want to get ripped off. Any feedback would be appreciated ..

resharp001

Who the heck installed your gears and did not include a break in checkup? That should just be standard protocol in a regear job....should not cost extra. Yes, either you should take it back, or you should drain the oil, remove the diff cover and take a little look yourself, refilling with new gear oil. Honestly, a lot of these shops in TX are a bit lazy. They'll just drain your oil and look at it without even looking at the actual gears. You can easily do it yourself and see if anything looks abnormal. If you're uncertain, just take some good pictures and post em up.

CrackerJoe21

Customer service seems to be seriously lacking everywhere these days......sign of the times I suppose?

un lupis

Good shops and only good shops include this , it's part of covering their ass .
Looking at wear pattern and any other issue that could lead to failure of their install would be something that if I were a shop owner , I would want to know .

The gear lube after brake-in has been used up after about 700 Miles and is heated by the process to the point of being more harmful , I usually like to see a change of lube at 500 Miles .
Opinions may vary , but call them and see what their policy is .

resharp001

Around the DFW metroplex, I think just about every shop includes this in the price. Heck, I think even 4WP does too. The only time I wouldn't expect it is if you pay some individual on the side, or a real fly by night shop. Maybe it's different across the land. Shops should also advise a customer on proper break-in procedure, but I find that much less common. Most just send customer on their way.....jumping on the interstate for their 1-hour 75mph drive home.

jk_southwest

Interested in what you think of the 5.38 ratio. What size tires are your running.

I will be upgrading to 37" tires and I am trying to decide between 4.88 and 5.13.

resharp001

I would highly suggest you go 4.88. I have 5.13's and run 37" Nitto Trail Grapplers. It's more aggressive on the highway than I would prefer. I run 3k RPM in that 70-75mph cruising speed. Mine is not a DD, more of a toy, so I don't mind sacrificing fuel economy for off road performance. The big difference is I don't have that rubi TC, so I wanted the lower gearing. Since you have the rubi TC, going 5.13 would be WAYYY overkill with the 3.6L auto and rubi TC IMO. 4.88 would be nice on the pavement for you.


***I have to admit, when I saw the OP and 5.38 I just assumed had the 3.8L. OP, if you have a 2018 with the 3.6L, are you running 40's with those gears?

jk_southwest

Thanks for the input. I am leaning toward the 4.88 setup.

TheTank

I'm running 38" Nitto Trail Grapplers with the 5.38's gears. It's a noticeable difference from the stock 4.10s I had. Also installed the Flashpaq, I do about 60mph at around 2k rpm... Personally I don't regret getting them at all!

resharp001

You have a 2018 with the 3.6L?