89 MJ

I would check for vacuum leaks around the intake manifold, especially where the manifold bolts to the head.

I think we'd probably need current pics and more details on what the truck is like currently in terms of engine, trans, mileage, etc.

I'm surprised this hasn't sold yet. Looks like a straight and solid body. Figure also what a 4L80 is worth too. Then these later small blocks were often times a roller cam block. They didn't all have the roller cam, but I think they all were machined for a roller camshaft.

Looks like a nice straight and solid starting point, although not the best taken care of for only 82k miles. What do you mean by a heat pump though?

August 2026 - Grandpa's Truck Preserved by @jodawill Build Thread https://comancheclub.com/topic/75321-grandpas-truck/ Year/Model 1990 Pioneer Drivetrain 2WD, 4.0 liter, automatic transmission Cooling Stock Electrical/Ignition 100% stock Suspension/Steering 100% stock Interior It's nearly 100% stock. I installed a new stereo recently, but I intend to have the original repaired eventually. Besides that, I've upgraded to Infinity Reference speakers and replaced the carpet padding with Dynamat and Dynapad. I also removed my grandpa's cup holder from the window after I replaced the weather stripping because I was afraid it might have caused the leak that ruined the original window regulator. (Sure, the cup holder wasn't stock, but it had been there since the beginning!) Brakes 100% stock Lighting 100% stock except for the headlight relay harness I just installed. Exterior 100% stock with the original bed cover my grandpa bought in 1990. Interestingly, it still has a sticker on the back window that he added before he bought the cover. Since it's always been behind the cover, it still looks like new. Wheels & Tires I'm using the original rims. Two of the caps are missing due to wear around the rim. I won't take any chances driving with them on until I get the rims repaired. Best MJ Story This truck has been a constant throughout my life. My family moved around a lot when I was younger, but my grandparents always lived in the same house, and in the garage, there was always grandpa's truck. He used to pile us up in the front seat to go get some ice cream at a local diner called Poor John's. It was the place where all the old men would gather to drink coffee and smoke cigarettes. The smell of the place is burned into my mind forever. Vanilla soft serve, coffee, and cigarette smoke. It was always just "grandpa's truck." It was so unique, I could only associate it with him, but I never really thought about the fact I had never seen one like it before. In June, 2023, someone called to tell me that my grandparents had listed the truck for sale. My grandpa wasn't in good health, so they had decided he shouldn't drive anymore. It had never occurred to me that there would ever come a time that they would try to sell it. I guess I had always assumed that my uncle would have inherited it, then it would probably sit in a shed for decades. After a very short and panicked discussion with my wife, I called and asked if I could buy it from them. They said someone had already agreed to buy it and they were waiting for him to come pick it up. Thankfully, the guy never showed, and I became the steward of this truck on June 20th, 2023. I drove it straight to my father in law's house to repair a few problems it had, including a broken window regulator. Several people stopped to look at it while it was in his driveway. That was the first time I had realized how special the truck was. It wasn't just grandpa's truck anymore. It was special in its own right. That December, my grandpa fell and had to go to the hospital. He became very ill while he was there, and we eventually lost him in February, 2024. For a long time, the truck mostly sat in the garage. I didn't want anything about it to change. I felt like every part I replaced put more distance between us. I think that started to change when it didn't smell like him anymore. Around late fall of 2025, I finally felt like I was ready to do something with the truck. I started with the gas springs. The window on the cover wouldn't stay up anymore. As silly as it sounds, it was hard for me to throw out those original springs. But I knew he would have wanted me to do it for him if he was still here. I bought a bunch of tools during the black friday sales, then I got to work. Once I got in there, I was surprised by how much work it needed. He had always taken care of it, but a vehicle that old just ends up with a lot of worn out parts that just haven't "failed" yet. Eventually, this project turned into a full restoration, which is still ongoing. I knew almost nothing about automotive work when I started. I'm not sure if I would have had the guts to take on this project if I had known from the start what I would have to learn and do, but I've enjoyed learning all these new skills, and it's been a big confidence boost. It's definitely hard to see things change, but I realized that the alternative is to allow the vehicle to rot. I know my grandpa would have loved to see this truck fully restored. It's my way of honoring him. I think one of his biggest fears was that he would be forgotten when he was gone. I hope that by preserving this truck, he will be remembered for many generations to come. CC is Awesome! Why? I'm not sure I would have been able to do much of this work without the forum. For every question I've asked here, I've probably solved 20 other problems by reading through old threads. I've never considered myself mechanically inclined, but with the help of all the members here, I'm finally learning. I'm grateful to all the members here who've put countless hours into researching and helping strangers like me who pop in and out over the years. This website is an invaluable resource.

If I remember correctly, it was @A-man930 that did the short throw and does not recommend doing it DIY.

I am skeptical of it saying it fits TJs, YJs, and XJs because I know TJs for sure have different shifters compared to XJs.

I wouldn't bother with the stock linkage. I'd recommend going with something like linked above.

Do you want to spend a long time building the truck or do you want to drive it? I’d find a better shell and swap the parts over.

Maybe because of the roll down rear window?

Looks like that was probably a good buy

And the Comanche badges to be in the right spot on the fenders

Glad to see this update!

Looks like a nice one! I was wanting an LJ for years, and my dad still is, but with how picky and cheap we both are, neither of us found the right one. Now that I have the JL, I feel like I'd have a hard time going back to a 4.0 in a Wrangler . I don't think there is a modern Jeep that is anywhere near as cool as an LJ though.

I'll agree with everyone that flushing the cooling system is absolutely crucial. I'll throw my experience out there, what I think some of my culprits were, and how I fixed it. For full transparency, here is my setup: 96 4.0 block, head, and exhaust manifold, stock Renix engine management, a high altitude CPS, a bored throttle body, stock fans, AX-15, 31s, and 4.10 gears. Running on the interstate (figure 72-80 mph range depending on traffic flow), my truck would overheat over time. The first time took roughly 40 minutes. This ended up being a partially clogged radiator. The second time happened after about an hour and a half. I believe I have solved this with a high flow water pump, the truck stays near 195-210 now. I think that there are a few things to blame here. 1. Obviously the radiator was bad (the block was spotless when it was installed) 2. High altitude CPS advances timing something like 5*. Too much timing does make an engine run warm and my truck has lived around 900 feet of elevation during my ownership. 3. The heater core was partially plugged and has since been replaced. 4. Sustained RPM. My truck turns ~2750 RPM at interstate speeds. That is a lot of RPM for a long time when I don't think that the cooling system was designed for it. Ultimately, my truck wanted a high flow water pump to deal with this.

Flagstaff trip last weekend. Hit Schnebly Hill Road in Sedona on the way and some forest service roads while we were in the Flagstaff area and also saw Mary’s Cafe where part of Two Lane Blacktop was filmed. Pretty neat place and a lot less warm than Tucson. I finally took the doors off too.

The first responders really liked this car at National Night Out last week.

Yes!

Hmmmm, if there is an oil filter relocation kit, I think I’d do that and then the oil cooler in series with the remote filter. I’m curious about this now too.

The knuckles, bearings, and brakes changed on the front axles in 90. I believe you can get a big brake kit for the earlier axles though, which is nice. I did not know that about the rear brakes.

I have a shirt that says safety 3rd. My favorite shirt to wear when wheeling

And possibly a little bit safer too

Looking forward to the next update!

I'm really liking this plan. There was a time where I wanted to make my truck have 33-35" tires, but now I am glad that my budget only allowed 31s. I'd possibly be a buyer if you've got an AX-15 to LS bellhousing you'd want to sell though, just make sure you won't want to use it first

If that thing is solid, that would be a much better buy than that $3500 truck he posted.