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Lift question

4K views 38 replies 12 participants last post by  Famtruckster14 
#1 ·
My 2006 LJ Rubi is in the shop right now getting a 6" lift.

I keep getting different answers on whether it needs any driveline mods. Does it?

If so, front? back? what's a good brand?
 
#8 ·
Well, minimum was 4". The 6" was only an extra $50.

The kit's already half on, so I don't think I'm returning it. I'm okay with this one as a first lift and upgrade as I go (or swap the whole thing out, heaven forbid).

With all this though, drivelines? It's sounding like I need to do the rear at the very least...
 
#10 ·
yes, at a very minimum, you'll need a new rear DS. luckily, since you have a rubi, you dont need to do a SYE.

if you kept the OEM DS, you would have very bad vibes and go through u-joints on a regular basis.

best advice I can give, research everything before buying. tons of good info on here and a couple other forums. theres pretty much nothing out there that hasnt been tried dozens of times over the 20 years our TJ's have been on the road. I cant imagine how much money i saved and where my jeep would be now if i didnt have the resources that are available
 
#11 ·
I read through some reviews last night and actually didn't find many negative ones. It sounds like they rebuilt their kits around 2012, so hopefully that helps.

Original 16" wheels, 35" tires. Stock 4.10 gears. It's still my DD, so I think that should be fine. I may upgrade in the future.
 
#13 ·
you're gonna want to get some aftermarket rims with 3.75"-4" back spacing to eliminate rubbing while turning and help lower the center of gravity a bit.

brakes should be upgraded to at least black magic pads and centric rotors, if not to a big brake kit.

at minimum, tie rod should be upgraded to a v8 ZJ tie rod, or better yet, replace the whole setup with curries steering.

if its an auto, get used to turning the O/D off every time you start it until you regear or you'll be lugging the motor causing lower MPG and soot build up.

reading user reviews can be tricky, as most reviews are done just after a lift replaced a bunch of warn parts and before that new lift has time to show wear or even be wheeled. forum discussion, while sometimes a bit rough, usually leads to much better information.
 
#14 ·
Right on the RC site it states a CV driveline recommended as well as a SYE if you do not have one. Also recommends 3.75" back spaced wheels. 35x12.50 are too wide for the stock wheels.

If your mechanic knows what he is doing, he should be aware of all that is needed to do the job correctly.
 
#15 ·
i looked at some chart this morning that seems to think that 4.10 gears are still okay, just in the 'econ' range...

The tires i'm getting are: tires
They don't seem too wide, think they'll be okay as far as rubbing for now?

i think pads are almost due, so i'll take a look at a brake kit

i'm sending over the tie rod to the shop, thanks

yep, i've gleaned a bunch already from reading through these forums, however discombobulated and scattered the info is... :p

i'm gonna let my mechanic do his thing. they don't necessarily specialize in these mods, but they're pretty all-around proficient. and trustworthy, i worked there for a couple of years. he'll get the job done. i feel bad pestering him with all of these "did you think of this" questions, lol
 
#16 ·
is it an auto or stick?

most of those charts are misleading as they are based on a 1:1 final gear ratio.

the only 35's i see on that page are for 15" rim or 18" rim. either way, generally, 35" tires are ~12.5" wide, which is way too wide of a tire to fit with an OEM rim. at a minimum, they would require 1.25" spacers, but ideally, new rims with the proper back spacing
 
#18 ·
Since you have Rubi, you don't need a SYE but as stated you need a
Double Cardan rear DL. Hopefully the lower rear control arms are adjustable so you can set the pinion angle to the DL angle (I believe its -1 degree).

 
#23 ·
the 42RLE with 35's, i know the pain you are about to realize.

decent with o/d off, as that basically makes it a 3 speed and has the final 1:1 ratio. Ideally, 5.38 gears should be installed on both ends.

to give an idea of RPM at given speed with the 42RLE and leaving the o/d on

31" + 4.10 gears @ 70 mph = 2146

35" + 4.10 gears @ 70 mph = 1901 rpm (2755 with o/d off)

35" + 5.38 gears @ 70 mph = 2495 rpm

sweet spot on the 4.0L for mpg and performance is 2400-2800 rpm. running lower will cause engine lugging and reduce mpg/performance
 
#24 ·
the 42RLE with 35's, i know the pain you are about to realize.

decent with o/d off, as that basically makes it a 3 speed and has the final 1:1 ratio. Ideally, 5.38 gears should be installed on both ends.

to give an idea of RPM at given speed with the 42RLE and leaving the o/d on

31" + 4.10 gears @ 70 mph = 2146

35" + 4.10 gears @ 70 mph = 1901 rpm (2755 with o/d off)

35" + 5.38 gears @ 70 mph = 2495 rpm

sweet spot on the 4.0L for mpg and performance is 2400-2800 rpm. running lower will cause engine lugging and reduce mpg/performance
What could be for the nv tranny if i run 35's?
Thanks in advance
 
#26 ·
OP, I hope you heed the advice of the members here regarding your excessive lift. Im sure your mechanic is all around proficient but not having the experience installing a complex lift along with unknowing effect of driveline angles, needed gear ratios, wheels backspacing, etc..of a your jeep will result in never ending issues, vibes, and costs.
Congrats on being a new jeep owner but don't expect the same ride quality and drivability after the lift. Personally, I would've went with the 4"lift and took that $50 to apply it towards a 1"bodylift. More is not always better when it comes to lifts.
 
#31 ·
Alright everyone, I got my jeep back yesterday. I now have to jump to get in or out. and i'm a tall dude...

-I got 1.5" Spidertrax, no rubbing (on the road at least).
-Driveshaft was custom, so I'm hoping that's good.
-I got the ZJ tie rod upgrade
-Handling on the road is fine so far. It likes to move the wheel, but i think that's just the big tires
-I DO have to turn off o/d. Once that's off, it sits around 2900rpm, which is probably a little high, but i'm taking that over 1900...

*re-gearing and upgrading the axle brackets where the arms connect i think are my next steps.


Before: (old pics, all i've got)
Land vehicle Vehicle Car Jeep Jeep wrangler

Land vehicle Vehicle Car Jeep Jeep wrangler


After:
Land vehicle Vehicle Car Jeep Automotive tire

Land vehicle Vehicle Car Tire Jeep
 
#32 ·
Well, just in the offchance anyone is still reading, here's an update:

I've taken it offroading, everything went fine (except for losing a nut holding the airbox down). I had to take it a little cautiously as I no longer have the under-armor (for the oil pan area).

Does anyone have any suggestions for under-armor on a long-arm lift? The old plate doesn't work because of the long-arms.

I'm going to re-gear very soon. I think I'm going to attempt myself (i worked a few years at a mechanic and am not afraid of hand's on work. :) ). Going for the same ratio as factory, I would need to re-gear to 4.63, but since that isn't an option, 4.88's probably. or would you suggest 5.13's? I have the stock Rubicon axles and everything, any upgrades I need to do there, or can I trust those parts?

I want to reprogram the speedo as well. Silly me, I forgot that I now go faster than my dash says and got pulled over (officer was kind and let me off with a warning). Any suggestions on which programmer to get?
 
#33 ·
5.38 gears for the 42RLE with 35's, even well experienced mechanics usually opt to let a diff specialist complete the regear.

savvy and UCF both make solid oil pan skids.

if properly setup and aligned, it should handle very similar to a stock vehicle. its not a jeep thing.

speedometer uses and electronic pickup. speedo healer, dakota digital, and a few others can be used
 
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