Gearing for 40's on UD60's........ 4.88 or 5.38?

[Zandcwhite]

Split the difference and go 5.13's? It is a 392 so you may want to stretch its legs over 100mph every now and again.

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[MrJonnycat]

Split the difference and go 5.13's? It is a 392 so you may want to stretch its legs over 100mph every now and again.

That’s what I did!

 

[GRN JLLO]

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Mine has the same issues. I have a Metalcloak 3.5 in lift. I have the Fusion axles, PSC Hydraulic ram assist with PSC steering box, and the 2.5 ton steering from Fusion. The Fusion steering is top mounted and my pitman arm hits when going over dips. It does not hit under articulation when wheeling but if you have any spirited driving on dirt roads with the sway bar disconnected, it will hit. I installed Rock Crawler 4.5 inch coil springs yesterday and based on my measurements, I gained about an inch in clearance. I think the Metalcloak springs had sagged a little bit. I will let you know if it still hits.

 

[chevymitchell]

So I'm switching over to UD60's on my 392, and I'm having a hard time deciding whether to go 5.38's or 4.88's on 40's. It's my daily driver, and I do use the freeway from time to time as well, but I'm not sure if the 5.38's will be too much for it. Knowing the transfer case is 2.72:1, and NOT 4:1 like all my other Rubicon's I want a good crawl ratio. I would love to go 5.13's, but that's not offered. Anyone have any real world experience with this?

I have a Rubi transfer case for sale. $1600.

 

[SargeRubi3.0]

Old thread revival. do I have to do anything special to run ud60 on the all time 4x4 on the 392?

 

[Qwest4air]

I ran into the same issues, I had a 4 inch metal cloak lift and the tie rod, was tagging the Pitman arm all the time, granted the metalclaok might ride a little low, so what I did is, I bought the ACOS adjustable spring perch with the Hydro bumps, and that solved my issue. The Hydro bombs really helped a lot.

Does anyone else have fusion axles installed in a jl? I’m in the process of installing some now and have some clearance issues in the up travel on the driver side, the tire rod wants to collide with the Pitman arm off the steering gearbox.

And it’s current set up I’m only gonna have about 2 inches of up travel on a 3 1/2 inch lift.

 

[Tank2112]

When I ordered ProRock 60's back in 2007, it was suggested by Dynatrac not to go any deeper than 5.13 to retain maximum ring & pinion gear thickness/strength. I was running 44" Pitbull Rockers, with Hemi 6.1, 545rfe. I will say that I did break 3 sets of rear ring gears, one ARB rear locker and split an Atlas transfer case (original style, claim newer ones are thicker) over the years until I finally dropped to 42" Treps.

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