chuck45

I was worried about pinion strength with 5.13's but I broke an Superior CM axle in the rear and Alloy USA CM axle inthe front and the gears where fine. The JK D44 has a much stouter pinion than previous 44's. My complaint with the D44's is not so much about their pinion strength as the lousy skinny thin axle tubes and lousy brackets and welding on the axles. If the rest of the axle were as beefy as the front 44 under my old 74 Ford F250 PU I'd be happy.

chuck45

You don't say that you have a Rubi so I'll assume you have 3.73's. So the answer to your question is yes. With 5,13's or 5.38's you will do much better than you do now.

redbull1969

Thank you for reponding Chuck 45. My Jeep is not a Rubicon it's the Unlimited and I put 37 inch tires on a year ago and lost all my power. I put a Max Energy programmer in it that helped but I still bog down on the uphill grades. One other question, if I go 5.38 gears will they be ok in the front end Dana 30? I don't do extreme rock crawling. Thanks

Finnster

Leesburg...I see you are in Roanoke, nice country down there.

chuck45

To be honest I don't know if 5.38's are even available for the D30. I think if I had a D30 up front, with it's smaller pinion, I'd go with 5.13's. You will see a huge difference with the 5.13's over the 3.73's; enough to make the expenditure very worthwhile. If you had a D44 up front I would definetly recommend the 5.38's over the 5.13's with 37's. Heck I've got 35's and wish I had 5.38's! If I recall my calcs correctly you'll be at 2410 rpm at 75 with your 5.13's and 37's. With your 3.73's the calcs show 1759 at 75 mph. I'd rather see you at a bit higher rpm than 2400 but that will be a huge improvement over 1759. If your tires are not a true 37" diameter but a little smaller your rpm's would be a little higher which would be a good thing. Hope that helps.

redbull1969

That helps tremindously finally a straight answer. So I'm settled on 5.13's. Now is there a particular brand of gears that's better than others?

Finnster

I bought Yukon's....from all I read they seemed to be as good as any others.

chuck45

I've had good luck with the Superior gears I have. I broke two axles and they held up. I hear Yukon is good. I'd prefer not to get Chinese gears.

BTW, after you get your gears installed let us know what you think.

b14400

I had a major problem with the auto down shifting, sometimes 2 gears when hitting small hills while pulling my enclosed motorcycle trailer with the stock 411 gears. Went to the 513, it doesn't hesitate a bit, and my towing gas mileage went up almost 2 mpg since there is no lugging anymore. I'll never make up the money the gears cost but I'm a much happier camper.

redbull1969

Hey Chuck 45,
I just called Absolute Offroad here in Phoenix, AZ and setup an appointment for June 8th to get gears installed. The owner Joe is pushing me towards the 5.38's because I have a 1700 lbs tent trailer that I want to tow on occasion. His shop uses exclusively Yukon gears he said Superior Gears make noise (I don't now). Anyway, the whole job out the down for $1300.00. Does this sound about write? Again thanks for your assistance.