• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

99 Jeep cherokee classic, 4BT cummins diesel

T

The Badness

NAXJA Forum User
Location
Fl
I have a 99 jeep cherokee classic. I also have a 3.9L cummins diesel engine (4BT) that i wish to drop in...i know im going to have to make some replacements and modifications to uphold the new torque. I just dont know what. Does any one know of the right tranny that can hold it? How about proper gears? Those kind of things. Anything would be great, thanks
 
Shooting from the hip here, but I think a dodge 47R should bolt up. The 4bt is basically just a 6bt with two cylinders lopped off. Also I seem to remember the box vans with 4bt's having gm transmissions (7004, t350/400?). I'd check the diesel swap forums for more reliable info.

Good Luck!
 
Right on...I remember someone speaking about a T400 being a transmission to choose...and by the way, will a 6bt even fit? (I'm trying to get as much torque as possible)
 
anything can "fit". Its a funcion of time, skill, money, and patience. The easiest way I can think of to make 6bt xj that didnt fold like a soggy taco under heavy throttle would be to mount a cherokee body on shorted dodge diesel frame. Without a ton (literally) of work a true 6bt xj would have the structural rigidity of two bricks conected to each other by a glued on plastic knife.
 
Turbo 400 (Grumman on GM Chassis)
T-18 (Grumman on Ford chassis)
47RH
NV4500
4L80E
Allison (Oshkosh chassis)

A stock 700R4 will not hold for long.
 
Thank you for that list goat...now does anyone know anything about the proper gearing? will the stock axles (8.25\DANA30) hold up? what about the transfer case (NP231J)?
 
What do you plan on doing with this truck? The engine weighs 705 dry without a flywheel...

Peak efficiency of a 4bt is 1700-1900rpm, with 1800 being optimal. So gear it accordingly based on purpose.
 
I wouldn't trust stock axles by any means. At minimum, toss some beef'd up 44s under, or even better a set of 'tons (stock would do fine).

Gearing depends on tire size and what you're doing with the XJ (crawling, mudding, DD duty, towing...?)

Goat has a good list of transmissions.

Take some 4x4x3/16" angle iron or c/u channel and plate the framerails front to back. Put some extra beef (plate your plate) around the motor and trans mounts. You're also gonna wanna beef up your crossmembers... Advanced Fab has some good stuff on that.

Might wanna look into firmer suspension.

If you have diesel questions PM me. I'm no expert but I know a thing or two.
 
great suggestions...thanks. I was thinking about the D44 possibility....I have access to a pair with 4.10 gears. I have 33x12.50 buckshot mudders...im not usually an extreme mudder, but ive always wanted to do this swap...i do, however; do alot of pulling people out of the mud and towing vehicles
 
i think this would be a bad swap for the use in mud. you wont have much horsepower compared to your torque output. and the main reason is that the front end will be super heavy and just sink. if this were a rock rig i would say go for it, this engine doesnt exactly overheat
 
The Badness said:
great suggestions...thanks. I was thinking about the D44 possibility....I have access to a pair with 4.10 gears. I have 33x12.50 buckshot mudders...im not usually an extreme mudder, but ive always wanted to do this swap...i do, however; do alot of pulling people out of the mud and towing vehicles
Click to expand...

4bt+4.10+33s wouldn't be too bad. Personally I'd go a little higher, maybe 4.56s, but you'd be fine with 4.10s. I dunno why you'd want to use an XJ as a recovery vehicle/tow vehicle, but hey if that's what you want then more power to ya.


95REDXJ said:
i think this would be a bad swap for the use in mud. you wont have much horsepower compared to your torque output. and the main reason is that the front end will be super heavy and just sink. if this were a rock rig i would say go for it, this engine doesnt exactly overheat
Click to expand...

Uh, no, wrong. You'll be happy with a 4bt in your application.

http://www.youtube.com/watch?v=BxxDxnlwsps
 
I saw a 4bt stuck into a Comanche. IIRC he had to go with a fair size lift because the engine was so tall. He had like a 8" lift and had the bumps lowered to limit the up-travel. The owner said the power was amazing though.

Here it is...http://www.youtube.com/watch?v=KyS9A3jbwLM&feature=related
 
Last edited:
Yes this motor is tall

lowres_6-17-09%20003.jpg


lowres_6-17-09%20002.jpg


lowres_6-17-09%20001.jpg
 
What build is that from Goat? I'd be interested in looking through that thread
 
could the motor have been lifted up higher if hood clearance was not an issue???

I am thinking of doing a 4bt in my cherokee and if I have to I will build a cowl hood just dont want to go over 6" of lift

thanks mike
 
Jeff Daniels Jeeps in Harleysville, PA has done 4bt into XJ swaps(along with CJ's YJ's TJ's). I seem to remember they weren't happy with the 4bt in an XJ. Something about the unibody making lots of rattling or something. Google them and drop them an email. They may have mounts for installing them into XJ's They do for removable top Jeeps.
 
Hey Goat, were you at the Pittsburgh Vintage Grand Prix a few years back? I talked to someone that had(same MJ that DieselSJ posted):
P7180023.jpg

P7180022.jpg

P7180021.jpg
 
Last edited:
You must log in or register to reply here.

Similar threads

Ecomike
85 diesel and 89 XJs and parts for sale
Replies
3
Views
2K
Ecomike
Ecomike
E
Who wants my jeep
Replies
1
Views
2K
tech1001
T
C
Ski jeep inquiry. 1992 jeep Cherokee Laredo prize
Replies
5
Views
1K
Anak
Anak
M
Jelp needed: Cherokee XJ rare interior
Replies
19
Views
3K
Goose_XJ88
Goose_XJ88
L
!!!!1989 jeep Cherokee 4x4 TRANS not shifting!!!!
Replies
17
Views
3K
Bent
Bent
Back
Top