Jeep Wrangler Forum - Reply to Topic
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum > 4.0 from a TJ

Join Wrangler Forum Today

Thread: 4.0 from a TJ Reply to Thread
Post Icons
You may choose an icon for your message from the following list:

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Additional Options
Miscellaneous Options

Topic Review (Newest First)
07-25-2013 08:18 AM
JoeyT Doesn't work that way. I doubt the car side TJ harness matches your dash, and your existing car side harness won't work with the engine side TJ harness.

Make sure you can find a YJ car side harness before you start.
07-17-2013 06:05 PM
Ianbeaulieu Well he is going to give me everything I need, like the harness and stuff, I would figure I can just plug back in the gauges and they would work
07-17-2013 03:38 PM
JoeyT I just put a 4.0 in my 4.2 YJ. It is not that easy. I ended up using the entire harness from the donor vehicle. At the very least you will need his harness from the firewall forward ( he can use yours to hack up to make his jeep run )

That being is a mess. In order to get the CEL and other warning lights correct, it is much easier to use his complete interior harness. You will also need his fuel tank, or you will need to install an aftermarket fuel pump.

In short.... if your 4.2 runs, take his 4.0, put it on a stand, and buy a 4.0 YJ with a blown engine and a rusted frame. Then do the swap.
07-17-2013 06:47 AM
90DesertTanYJ Not speaking from experience but I would think it would be pretty straight forward. The only thing that might be different would be electronics. Chrysler went to their own engines when retooling worn out molds for the 4.0 was more expensive than converting to an existing engine in their line up.
07-17-2013 04:36 AM
dukes-o-hazard Seem's easy enough from what I read 90 4.2 to 95xj 4.0 Swap Build Thread -
07-17-2013 02:15 AM
4.0 from a TJ

Hey, my friend has a 97 TJ and just rebuilt the motor, he is going to put a 350 in his TJ and said I could have the 4.0 in it, what all would I need to do this swap? And should I do it? I currently have the 4.2L

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -5. The time now is 12:47 PM.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC. is not in any way associated with the Chrysler Motors LLC