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Is it worth it to upgrade my 4.0 ZJ???

3K views 17 replies 6 participants last post by  Crasher 
#1 ·
I bought a 1997 Jeep ZJ about a year ago ($4000) and I'm getting to the point of upgrade friskyness...however, I haven't convinced myself that this is the rig I want to throw a butt-load of money into. It is a 4.0L Laredo with selec-trac but I believe it has a D35 in the rear, but it does have a factory tow package (in the process of getting spec sheet). The exterior is in pretty good shape for a 15 year old thing, and I just recently broke 150,000 miles! Long story short, would decking this thing out be worth it, or should I just wait and invest in a WJ or something else in a few years...? :confused: Thanks in advance for everybody's input.
 
#2 ·
All 4.0's had the d35 from the factory. It's fine for 31's.

I wheel the **** out of my 96 with only 2.5" and 31's. I can follow locked and built tj's on bigger tires all day long. And it doesn't take much coin to get to that place.

WJ's are harder to modify with computers and a slightly different front suspension design. And the engines are not as reliable, the 4,7 V8 sucks, and they managed the f up the 4.0, which should run forever in any other vehicle they put it in.
 
#4 ·
You may have to regear, but it's got the torque.

If you put some 4.56's in there it would roll 35's fine. If you do that though look for a d44a from a post 96 V8 and regear that instead of the d35. It will bolt up the same and be stronger, especially if you truss it in the process.
 
#5 ·
4.0 on 33's. as you can see from clearance, at this point it does not do major off-roading, but it will squawk the tires all day long. this jeep sees a lot of mud and hills and does fine. i am sure if i was gonna play with it all the time the d35 would break, but for moderate fun, it works fine
 

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#7 ·
The post 96 V8's came with d44a (NOT a D44, a d44a) in the rear. All zj's have a D30 in the front. You would pull the d44a out of a 96+ V8, bolt it in place of your d35, put new gears in the d44a in back and the d30 in front and be ready to roll.
 
#9 ·
Pick them up from V8 zjs in the yards around here any day. But this area has a lot of mommy wagon V8's that probably have never had their t-case shifter touched.
 
#11 ·
Bah! Wheel it till you break it!

If you're kind to the d35 (easy on the skinny pedal) then it shouldn't be too bad. There are people who run the d35 without problems.

I'm pretty sure texas was still running a d35 behind his 5.9 on short arms, with 35's and he wandered all over moab just fine. His driver fu is slightly higher than most though.
 
#16 ·
I have been to Moab a few times with the ZJ in my sig. Last time a friend came with his 98 ZJ with 31s, an Aussie locker in the rear, and a 2" BB. He did several of the trails without any problems. There is a wide range of easy to difficult trails there. There is something for everyone. FWIW, A 4.0 ZJ with a 242 tc, an HD 44 (44a) in the rear with an aussie, 33" tires, and a 3 1/2" lift will go more places than you can imagine with minimum breakage. This setup will go 90% of the places you would want to go.
 
#15 ·
I have ran a d35 on 33s for a year now and I try to get out at least once a month and wheel if you run it open and drive accordingly it will be fine. You don't have to drive like an 80 yr old lady but don't drive like some lunatic either.
And I believe Texas had a super 35 behind that 5.9.
 
#18 ·
Wasn't hard at all. The linkage was pretty straight forward. Had to trim the console some for the twin sticks. Aside from the Clayton LAs, it was the best mod that I did. I run a lot of the trails in 2lo and use 4lo and the lockers only when needed. It makes tight turns easier and with 488 gears and a 3.8:1 tc, I can descend very steep hills without touching the brakes. It makes for a nice slow crawling speed too. I'm probably going to put one in the TJ too.
 
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