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98 TJ 5.3 / 4L60E Conversion

14K views 48 replies 12 participants last post by  AEmedic 
#1 · (Edited by Moderator)
In the last week I have picked up "most" of a 1998 TJ. It will become my dream Jeep, eventually.

The TJ is missing the front Clip, including the radiator support and the engine and trans. The engine and trans being gone works in my favor, the rest just means more $$$.

I need to remove the tub and have it media blasted and any rust repair done. I may have the frame dipped and then coat it with POR 15 before I start putting it together. I'm not sure on the frame yet, as I tear into it I'll know how far I need to go.

I have lots of learning to do and I'll be living in these forums for awhile. I'll share what I can and appreciate any advice and constructive criticism anyone might have.

I have a 1999 GMC with a Vortec 350 with an automatic. I'm not sure if the drivetrain will work with the Jeep, we'll find out...
 
#3 ·
Apples and oranges on the T-case. If you can afford it an Atlas is great. You can get NP241C cases all day long for under $350 and they are pretty stout. I would base the decision solely on budget.

I've put an L31 (Vortec 350) in my project TJ. Although I'm using a SM465 trans the bolt pattern and spline counts are the same as the 4L80e, so the cases can interchange. I will be using an NP241.
 
#4 ·
I was talking to the guys at Novak and they are taking me out of the 4L80E. They explained that with its length, I will have an extremely short rear driveshaft, and that isn't a good scenario. They recommend that I go with the 4L60E. With that, I need to buy one, preferably one that is already adapted to use with the transfer case I plan to use. Speaking of the transfer case, I have be talking to a guy that builds Jeeps. He thinks the best route would be to build a D300 to work in the TJ. Opinions?

I am considering either D44 front and rear or a D60 in the rear and a D44 in the front.
I ordered Metal Cloak overline 6" front fenders, since I don't have any fenders up front... I will get their armor all around after everything else is done.

Since I won't be using the trans that is married to the engine, I need to figure out what I can reuse. I know that need to either have the harness modified or purchase another on. I assume the computer will need to be reflashed to work with the new tranny. The engine does not have AC on it but has the bracket. Does the computer need to be reflashed to reflect the AC, is the harness separate for the AC?

Thanks for any insight.
 
#5 ·
If I were you I'd look into the 700R4. It's basically a non-computer controlled 4L60. On the AC you won't have to change anything in the computer. Just remove the associated wiring from the harness. I recommend using a harness for an '03-'04 S10 with a 4.3. You just have to add a few injector wires. The big advantage is it's set up for the 411 computer which is much better than the black box. Just have to get a custom tune using a 5.7 express van as the base tune.
 
#7 ·
What is the most respected long arm lift? Not looking for the most expensive, but I don't want to buy crap either...
I figure that since I am going to have the Jeep stripped down to the frame that I might as well do it all at the same time and then coat all the frame modifications along with the frame.
 
#8 ·
What size tires you going to run? Long arms tend to be more of a hinderence unless running big tires. I probably wouldn't run them unless over 35s.
 
#9 ·
I was going to start with 33s until I get the overline fenders and flares all around, then I will move up to 35s...
 
#10 ·
You'd be best, IMO, to get a set of good short arms. The best compromise for a trail/road vehicle is an arm with a Johnny Joint at the axle and an oem rubber bushing at the frame. If you can weld, I would suggest going to a triangulated setup in the rear. Clayton has some nicely priced setups. Also can't go wrong with Currie/Savvy.
 
#19 ·
I decided to go with the Savvy / Currie 4" lift with Bilstein shocks. Am starting the install on the bare frame today. I'm hoping to find some written guidance for the install.
 
#12 ·
Has anyone had the pleasure of replacing the body mount torque rails? I have been getting ready to pull the tub so I can have it media blasted and realized they are pretty bad... I've seen the replacement units...
 
#13 ·
They are a breeze if you've done floor pan work before. Got mine from Key parts and they fit excellent.
 
#14 ·
I haven't done floor pan work but I at least know I can remove the torque box/channel and at least prep it for someone to tack the new one in place.
 
#15 ·
Picked up a 4L60 tranny out of an 01 Chevy and a NP231 out of an 05 Jeep. I'll have the trans rebuilt when I have the Novak adapter installed and I'll have the larger chain kit and the 6 planetary upgrade done when I have the SYE installed.
I also found a place to media blast the tub.
 
#18 ·
1998 TJ Vortec 350 build

I switched gears a little bit... I was able to get the 5.3 out of that truck, so that is my engine and tranny combo.
 
#22 ·
Any opinions on the best shifter for the 4L60E? I am going to be using it more on the street than the trail, so I need and want a standard style rather than a trail oriented shifter.
 
#23 · (Edited by Moderator)
The Rear D44 axle is on with the new Savvy/Currie suspension. I still need to install the adjustable track bar but it is just a little hot out...
 

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#27 ·
So, in the process of moving parts from the 05 donor the Christmas trees broke off the plastic clips on the frame that hold the fuel, brake lines and the wire harness. I am having a really hard time finding a source. Has anyone had any luck? The 5 tube clip from the 05 would work if I could find them...
 
#31 ·
So, I’m getting ready to mount the transfer case on the Novak 4L60 adapter. Thinking about clearance and driveline angles with the 4” Savvy/Currie lift, what is a good clocking position? My thinking is, just under level with the rear output shaft position...

Any insight from the masses?
 
#36 ·
The front isn’t a “true” D44...I have trussed the D30 long side tube and will eventually upgrade the shafts with CroMo units.
 
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#37 ·
Here is a test fit of the dash and a picture of the AutoMeter gauge style I chose.
 

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#40 ·
I am doing the same swap - 5.3/4l60e/NP241c in a TJ.
I noticed from your engine bay picks that you removed all the components on the driver side inner fender - windshield washer tank, evap purge valve, etc. Did you completely ditch them or relocate them?
I need to make some room there and am not sure what needs to stay and what needs to go for the 5.3 swap.

Thanks
 
#42 ·
The washer tank is now installed in roughly the same place that it was stock and all the EVAP is back by the fuel tank. The computer and the air pumps will be on the package tray. I’ll fit the horn and overflow over on the DS, probably...
 
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