Regearing for 35's

[Philistine]

The PO of my MJ did a lift and 35's but did not regear the axles. I want to regear them to get the power back on the highway (I can't get into 5th right now) and improve offroading (a better crawl ratio). Would 4:88 gearing be OK? Would that make the RPMs to high for the highways? The MJ is mainly for offroading and camping. A guy I know is willing to sell me a HP D30 with 4:88's installed cheap (for less than I could buy the gears themselves).

[Pete M]

which rear axle?

 

be careful about deals that seem too good to be true. improperly set up gears can die in short order.

[Philistine]

which rear axle?

 

be careful about deals that seem too good to be true. improperly set up gears can die in short order.

 

I have an AMC20 in the rear (which I would regear to match). I know him thru a local forum, he's an upstanding guy and has had the axle on his rig for a while. He's upgrading to a D44 and is willing to cut me a deal on it.

[mjeff87]

if this is the rig in your sig line, with the 2.5, go 4.88's. I ran my 2.5 on 33's with 4.56's for awhile and all was good, then I stepped up to 35's. The 2.5 did "ok" with it for the time I ran it, but it just wasn't a good setup on the highway (offroad was good, though). Just not enough engine, combined with heavy MT tires (on steel 15X10's) and increased wind resistance the 6" lift created......I was pushing the four little squirrels to the limit. I ended up swapping a 4.0 in it to solve that problem ;)

 

My old 2.5 is still pulling faithful DD duty in pingpong's street MJ, too, 200K+ miles and counting.

 

Jeff

[Pete M]

I'm assuming 4.88s are available for the M-20? If so, then I'd definitely go that route. :D

[Eagle]

Actually, 5.somethings would be better for 35s, but since 4.88 is as deep as you can get for the Dana 30, that'll have to do. With 35" tires and 4.88 gears, your highway RPMs in overdive will be approximately 2190 at 60 MPH and 2558 at 70 MPH.

[Philistine]

Thank you for the input everyone. Looks like 4:88's is the way to go.

[wannabeMJ]

I'm running 4.88 in a dana44 under my YJ and I love it

gives me a good crawl ratio in 4low

[CWLONGSHOT]

Just a note... 4:88's and a hard core wheeler in a D30 will likely equal troubles... That pinion is MIGHTY small!! IMHO, if crawl ratios are what you want, go 4:56 for better strength and drop in a 4:1 in the T case.

 

CW

[Geonovast]

A quick Google turns up 39 on the ring, 8 on the pinion in a D30 for 4.88:1

[Eagle]

CW is correct. This is why 4.56 is the lowest ratio you can get for the D30 from Dana. All 4.88 gearsets are aftermarket.

[Philistine]

Just a note... 4:88's and a hard core wheeler in a D30 will likely equal troubles... That pinion is MIGHTY small!! IMHO, if crawl ratios are what you want, go 4:56 for better strength and drop in a 4:1 in the T case.

 

CW

 

I'm not planning on making it a hardcore wheeler yet. I'm thinking more along the lines of an expedition/mild trail rig right now. Something that could handle say 80% of the trails out here.

 

Down the road I do want to be able to run the Rubicon and Fordyce sometime but I'd proabably look into building up a Wrangler instead for that kind of wheeling (something with a shorter wheelbase).