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2 Posts
Discussion Starter #1
Howdy Everyone, new guy here. How's everyone doing?

I'm a member of a few Jeep forums but haven't been able to get any info regarding diesel swaps on those forums.

I have a 2002 WJ, 4.0l, standard 3.55 gears, 3" IRO lift, on 32s. It's my DD, averaging 16+ mpg.

I wasn't sure where to post, I didn't see a "Jeep" section when I browsed through quickly. Looking to swap in a diesel and needed some direction as to what would be the "easiest" motor/trans/t-case/driveline combo to put in.

Thank you 馃槉

1,459 Posts
Welcome to 4bt swaps - General discussion works for this question.

At the top of this page, there is an extensive FAQ, very helpful.

I never got the "Jeep thing", I was driving Cornbinders (International Harvesters) back then. We need a little more information to help you along the path.

After some Googling "2002 WJ" translates to Grand Charokee - 4.0L translates to a straight 6 cylinder engine.

Does daily driver include severe off-roading?

Exactly what transmission (including model #). 4 speed manual, 5 speed manual or automatic. Makes a difference - lots of potential issues

Many automatic trans do not stand up to the low RPM torque of the 4bt engine - adapters are very expensive - and often not available for unusual transmissions.

I think folks have used the Jeep 5 speed transmission in 4bt swaps - I have no idea what transmission model or year range - Suggest you search through the Transmission, Adapter, Transfercase Discussion

The FAQ lists several Jeep transmission links.

Many automatic trans do not stand up to the low RPM torque of the 4bt engine - adapters are very expensive - and often not available for unusual transmissions. I did find this reference to a Jeep auto trans - did not bother to read it

A few quick comments:

1. Pay attention to drivers-side vs passenger-side drop when getting a transfer case.
2. Adapting to your existing drive train might be the cheapest route (if it is up to the torque).
3. Lots of engine bay length for the 4bt .
4. Other drive train options depend on if the 4bt came with a Ford, GM or SAE adapter - Rare options are no adapter (gonna have to buy lots of parts) or someone has swapped in Dodge 6bt parts.

2 Posts
Discussion Starter #3 (Edited)
Current transmission is the 42re, 5 speed automatic. I'd prefer to leave it auto as my wife does take my Jeep when I'm working on her truck. I already know that that specific trans is not rated for the torque of a 4bt or any other diesel would put out. I don't do any severe offroading, just the occasional trail, nothing too serious. Thanks for your help, I'll look through the sections when I get some time.

11,061 Posts
The 42RE is computer controlled so if it could be adapted to a 4bt you'll need an outboard control unit. Not all that sure about that transmissions strength. You'd also need a different torque converter for a diesel with a stall speed in the 1300 RPM range. I've read that the 42RE can be rebuilt using 46RE parts to give it more torque capacity. Might need a different transmission. Ones commonly used are the 46RH and 47RH that came behind the Dodge Cummins. They are essentially the same except the 47RH has a lock up torque converter. You could also use a 47RE but that would require an outboard controller also. The RH series are mostly mechanical. Requires a electric switch to turn on the OD and lockup. Also, the engine adapter plates used on the Dodge would bolt right onto the 4bt.
If you decided to go manual transmission, not many of the Jeep 5 speeds get used due to the lack of adapters and strength. A Ford/Mazda M5R2-OD is a possible but that one isn't super strong. Russ is running that one. The Ford ZF S5-42 is a possible option. One commonly used is the Dodge NV4500. Of course with any of these transmissions, manual or automatic, you have to figure out the transfer case situation.
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