1990 RENIX 5 speed swap with 1998 HO Automatic

So I started the swap by completely stripping out my 1990 XJ. Engine, 5 speed transmission, transfer case, all wiring . So far these are the differences found after stripping out the 98. I was going to start this thread when I completed it but it’s a lot of stuff.

1. All the electrical connectors are different.
2. The dash is mounted different. (You will have to remove brackets off of the donor XJ).
3. The steering column is different and mounted with an aluminum bracket which is secured to the brake pedal bracket and the left side inner firewall where the fuse used to be.
4. There are several different cutouts on firewall that changed between the years.
a. Main harness cutout is round on 98 and square on 90.
b. Needed new cutout for harness that goes to fuse box.
c. Needed new cutout for Automatic linkage to transmission.
d. Needed new cutout to relocate the antenna due to fuse block being in the way of old one.
e. Cut out for the steering out of the cab mount different and the hole is oblong and needs to be round.
5. The fuse box is on the passenger side.
6. The electrical going to the fuel tank has four wires and the 90 XJ had only three. (So I'm changing fuel tank out too)
7. The center console is different along with the dents in the hump. I still haven't messed with that much. I will be writing more about that when I get to it.
8. The old brackets on 90 XJ that hold steering wheel and heater up have to be removed.
9. All but one of the heater bolts line up. I will have to drill out one location. The cutout where the A/C and the heater core come through fire wall is smaller on the 98. I filled it with sealer.
10. The headliner fit just had to move a bracket from the donor to the 90 that holds the interior light in place. Fastened with sheet metal screws.
11. The wiring harness from front to rear is split and goes on both sides not just the drivers side like the 90.
12. The e-brake handle is different but still fits in the cutout that is there. One bolt will fit hole it in place and then I had to Fab a piece from donor and used a self tapper on last one.
13. Charcoal canister is in the back under XJ and not in engine compartment like the 90.

Donor 1998 XJ



Recipient 1990 XJ 5 speed

Steering column mounts

There was a Big difference with the steering column mounts. The 98 was a column mount and a dashboard mount. The mount in the 98 had 24 spot welds holding it on it was a pain to remove.

1998 mount



1990 mount



Mounts installed in 1990



I chose to use bolts instead of welding, nuts hold it on it the compartment where wiper motor goes.

On the 1990 where the harness went into the vehicle it was square the 1998 was round. I cut a piece off of the 1998 and screwed it to the 1990 with some sealant behind it.

The fuse box from the 1998 was on the driver's side I had to move to the passenger side. I used the plastic trim piece as a guide and then had to relocate the antenna coming from the fender because it was in the way.

The mount that holds the steering column was reinforced to support the airbag. It mounts to the dash board bracket, the brake pedal bracket and the left kick panel. I used self tapping bolts and nylon insert nuts to secure it to kick plate.

Vapor Canister

The vapor canister on the 1998 is located underneath the vehicle towards the rear. One of the bolts from it goes on the seatbelt nut mount and the other 2 are connected to a bracket inside under the seat. I removed the bracket from inside the 1998 by drilling out the welds. I placed the canister where it should go with the one tab on the bracket underneath and then marked and drilled the holes to secure the other two tabs. After I drilled the holes I pushed the bracket with the studs through the floorboard under the seat and secured them underneath.

Engine Wiring Harness

Putting the engine wire harness was pretty simple. I mounted the bracket for the relay box and the ECM with self tappers. I had already made the holes I needed for the harness to pass into the passenger compartment. I used some zip-ties with an eyelets to secure the harness to the wall.

Looking good. Sure is one hell of a project.
Now hurry up and get it finished so we can go wheeling again.

Glenn B said:

Looking good. Sure is one hell of a project.
Now hurry up and get it finished so we can go wheeling again.

Click to expand...

I'm ready to put engine back in maybe tomorrow or Monday hahah. You coming to help??

Monday might work. Will check with the wife when I get home from work.

Monster3663 said:

I'm ready to put engine back in maybe tomorrow or Monday hahah. You coming to help??

Click to expand...

Emergency Brake install

The 1998 and 1990 e-brake handle are different. The 1998 mount is shorter and offset. The rear mounting hole on the hump was the only thing the same. I used the rear mount screw as a guide and then used a self tapper on the drivers side mounting point after bending the mount to conform to the hump. For the front mounting screw I cut a piece of the hump from donor 98 e-brake off to gap the distance where the old mount was. I gobbed some sealant under the cut to seal any voids and then used the same screw it had normally used.

Hood Release relocated

The hood release had to be relocated due the dashboard mounting bolt going where the latch used to be on the 1990. If you notice the trim pieces are different too, the one on the right is from the 1998.

So I installed the dashboard and the center console today. The dash went in pretty easy with the mounts I installed before. I had to add two other attachment points because the points on the 1990 were not where I needed them. I just put a piece of metal between the old attachment points. Earlier in my post I showed how the side bolts were attached to the lower sides. I was able to remove the the grommet the wires went to the door trough and put a nut behind the bolt in the frame wall. The steering column was offset to the left and did not match the old cut out for the shaft to the steering box. I cut out a piece of sheet metal and made a template from the donor vehicle. I the made the existing hole bigger the put the plate over the area.









The center console was easy the only problem was the hump is shaped different and the console bracket did not work that good. We made a new bracket out of sheet metal. The air bag control had to be relocated due to my e-brake handle being moved back a bit. It was remounted under the drivers seat.