99 tj 4cyl to 6 cyl swap???

99TJ

Active Member
Joined
Aug 20, 2009
Location
Charlotte NC
Hey I have a 99 tj with a 4 cyl 5 sp and I bought a 6cyl w auto tranny out of a 99 Cherokee sport 4x4 I got wiring the ecu and shifter Assembly out of the Cherokee will all this work or do I need to get diff parts any advice would be nice thank you
 
i dont think the wiring will work unless you do alot of cutting and splicing. Get a tj harness, it will save you the headace. i have done this swap with my tj so be ready cause its not a simple swap.
 
Like stated get a harness from a junk yard from a 4.0 TJ, Then replace your harness back to the firewall block.

Of course will need to relocated the Motor Mounts, Exhaust, I think the radiator will work with a 4.0. Not sure they had trans coolers on a 99, Good idea to run one. Not sure if the trans has a separate computer or if it built in with the ecu. Might check that.

Drive Shafts may be fun.
 
burrellsjeep said:
Like stated get a harness from a junk yard from a 4.0 TJ, Then replace your harness back to the firewall block.

Of course will need to relocated the Motor Mounts, Exhaust, I think the radiator will work with a 4.0. Not sure they had trans coolers on a 99, Good idea to run one. Not sure if the trans has a separate computer or if it built in with the ecu. Might check that.

Drive Shafts may be fun.
Click to expand...
Yea the xj had a tranny cooler. Rear DS will be the fun one. SLE will be almost required.
 
im doing this same thing as we speak, but my engine/tranny/ etc.. is from an 03 and going into a 97 so i have more headaches with the swap. the harness from an XJ willl NOT work in your TJ... i been down that road.
 
so basically this is more of a headache than its worth it seems like probably just find an engine and tranny out of a tj??
 
99TJ said:
so basically this is more of a headache than its worth it seems like probably just find an engine and tranny out of a tj??
Click to expand...
You got it! Aside from not taking thee body off the frame it basically feels like a complete rebuild of the jeep..at least thats how i felt about it when i was done.
 
Can I ask why you are swapping? I have a 4 cyl too and was set on swapping over to a I6 until I spoke with some people about gearing. I then drove a 4 banger with 4.88's in it and I was sold. Unless you have to drive 65+mph a lot it's cheaper and more practical to just regear. And depending on what size tires you want to run you might not even have to go too short of a gear.

If your still set on swapping then yes. Find a motor, trans, harness, ecu, tcase, from a 97-00 (only the first part of 00 will work. 97-99 to be safe) and driveshafts. You'll still have to relocate your motor mounts, but other than that everything else will be plug and play.
 
Well I'm. Running 33x12.50 with 3.07 gears now and I have absolutly no power even with the factory tires it was bad I got the 3.07's on a really good deal and I didn't have time or money to wait for a axle with 4.10s like what was in it a d I got the Cherokee really cheap so I wantEd to swap it so I guess I'll sell what I got and look for one out of a tj
 
99TJ said:
Well I'm. Running 33x12.50 with 3.07 gears now and I have absolutly no power even with the factory tires it was bad I got the 3.07's on a really good deal and I didn't have time or money to wait for a axle with 4.10s like what was in it a d I got the Cherokee really cheap so I wantEd to swap it so I guess I'll sell what I got and look for one out of a tj
Click to expand...

The motor could work its the tranny that is the problem. I do know someone that would be intrested in the tranny. Why do you have 3.07's? 4 popper tj's came with 4.10's. At least when I bought mine in 96 it did.
 
Well what about using a 5 speed tranny out of a Cherokee 6cyl would that be easier ? I have 3.07's cuz my rear 4.10 axle messed up and I couldn't find another one
 
99TJ said:
Well what about using a 5 speed tranny out of a Cherokee 6cyl would that be easier ? I have 3.07's cuz my rear 4.10 axle messed up and I couldn't find another one
Click to expand...
Yes the 5 speed behind the 4.0L in the xj and tj and yj were all ax-15's up to 99 IRSC. The main difference in the Tcase is the input and the shift plate IIRC.
 
I can't remember everything, but I know a lot of the sensors and other small things do not swap between the Cherokee and the TJ. You can use that motor, but you'll have to swap a lot of them. The thread I linked talks about it. I think he bought a XJ motor too. I have 4.10's and am running 33x12.5's and although it's not a race car, it does fine. Defiantly just go with the regear. I know a shop in Wilmington that does will do the swap including Yukon gears for $875 OTD.
 
99TJ said:
thanks for all tthe advice guys i think i may just regear how do i find out what axles i have (dana 35 dana 44 etc...
Click to expand...
I would bet you have a D35/30 combo. It is the most common set under your year TJ. I'm not sure when the RearD44 was introduced but I do know it was not found in 4 popper TJ's.
 
McLeod's Junkyard in Sanford has a 4.0 4x4 TJ, not exactly sure what year, but when I was there last week the engine, trans, Tcase and axles were all still there. No wheels and it looked like it might have taken a mild rollover.
 
kyleg336 said:
McLeod's Junkyard in Sanford has a 4.0 4x4 TJ, not exactly sure what year, but when I was there last week the engine, trans, Tcase and axles were all still there. No wheels and it looked like it might have taken a mild rollover.
Click to expand...

thanks man I might have to go check that out this week
 
Just be sure to call them first, just to make sure it's still there before you drive from Charlotte. They are closed Sunday and Monday and open Tues-Sat 8:30-5:00. Think their number is (919) 776-9274.
 
Back
Top