any major jeep work will have to wait for a bit. i see some say 4.88 and some 5.13 or lower. seriously thinking swapping complete axles when the time comes. not a fan of the 30 and 35 axles it currently has.
Bad gas mileage
- Thread starter Kyle559
- Start date
I'm about to do this exact thing - Getting my LJ regeared to 5.13. Do you still turn off OD every time you drive after the regear? Or can I stop turning it off once I'm running 5.13?
For what size tires? For 35's you'll still likely be turning your overdrive off much of the time, for 33's you will likely be good with the OD on.
For 33s. Having never driven 5.13 I'm really curious to feel the change from 3.73. The thing drives like a real bear at the moment.
You'll love the increase in performance and mpg with the 5.13 gears, it'll drive like a new Jeep.
Make sure to tell the shop to ONLY fill your axles with a conventional gear lube after they finish the regearing. Refill it with conventional during the first gear lube change too. New aftermarket gears will run too hot during the break-in if they're lubed with a synthetic gear lube. Yes, that's true.
P.S. If some shop monkey tells you they only use synthetic, tell them to source conventional for you, allow you provide your own conventional gear lube, or if they refuse tell them you'll take it elsewhere to be regeared.
I had a set of new RGA gears overheat when against my better judgement I let myself get talked into using a synthetic gear lube. The gear guru I took it to when they started whining looked at the gears and within seconds accused me of having used a synthetic gear lube after telling me they had overheated.
I had a set of new RGA gears overheat when against my better judgement I let myself get talked into using a synthetic gear lube. The gear guru I took it to when they started whining looked at the gears and within seconds accused me of having used a synthetic gear lube after telling me they had overheated.
Good to know, thanks! I'll make sure to confirm conventional only. It'd be a real PITA to spend all that money just to have it immediately get ruined..
My 05/6-speed (I know yours is a 42RLE) with 33’s and 3.73 will get anywhere from 10-13. I just got back from a quick weekend trip. About halfway there, I filled up (half tank) and it said I got 10.3 on that half tank. Filled up again later (half tank again), and it said I got 13.8 on that half tank. Gonna check it again tomorrow to see what I got on the way home.
You need a more consistent point for measuring, where half tank actually is and what gauge shows is typically two different things.
Bighammer
TJ Enthusiast
Naw, that shouldn’t matter, he’s using the odometer (miles traveled) and the fuel receipt (gallons used) But I would think it would be much more accurate if you were to average the numbers out after several fill-ups.
My dad (RIP) used to check his mileage after every fill-up. He was somewhat obsessed with knowing his mileage, but he could tell exactly how mileage was affected by various changes over the life of the vehicle.
I just checked mine after two tanks worth of driving and I got 12.9. This was with my 2005 Unlimited, 4.0, 42rle tranny, 31” tires, and the OD locked OUT. I’m in the middle of the next tank, and for comparison I’m leaving the OD operation up to the Jeep! I’m not sure what to expect.
I have a 97 4.0 auto on 35s with 4.10 gears and get just over 10mpg. With the same setup and 33s I would get exactly 10mpg. My Jeep just passed smog, no CELs, new plugs, wires, cap/rotor O2 sensor air filter and CAT. I just figured this is what I get for having a Jeep. Anyone on here actually get there Jeep from 10mpg to something better?
(I have the right spedo gear as well.)
(I have the right spedo gear as well.)
So my Tj is a 2001 with 4.88 gearing and I'm about to bump up to 35s I've got a 4 inch lift and my entire drive train is rebuilt to perfection and right now I'm on 32s and I'm getting 11mpg do you think it's gonna go up or down when I put the 35s on? It's also a manual and I may have a slightly heavy foot.
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