'72 J-4000 R&R

[RobGV]

Another new member here -- and I arrived with my pockets already empty!

A few years back I spotted a sad J-4000 sitting in a field a little bit outside of town. My '87 AMC Eagle had just decided it didn't like its head gasket anymore after doing a bunch of other work on it, so I was looking for a new driver while I made it sit in a corner and think about what it had done. For my part, I thought real hard for a bit about what might be wrong in my head that would make me interested in another project vehicle.

Anyway, showed up, the lady's husband had just passed away, she was trying to clear out all of his "clutter". Got the truck for about $400. Only catch was, it hadn't moved in about 6 years she thought.

WD-40, a battery, brake fluid, some gas, a little oil, and a little grumbling got 'er back on the road. Drove it right out of the field. Got to enjoy it for about a year, replaced the bench seat and did a little other work, then started losing one cylinder, then lost another, then another... at about the same time, the 258 was coating everything in the engine compartment with a lovely shade of yuck -- oil everywhere.

So what started as "let's rebuild the engine" turned into "let's clean the engine compartment", which became, "let's paint the truck!", which became, "Well, guess I have to take it all apart then."

I am not a clever man.

Here's the rebuild "starting". Everything -- and I mean everything -- under the hood looked like the right side of this picture, and that was after two sessions of scrubbing with soap & water and Simple Green:



After a little more cleanup, I discovered some new rattle can paint I wanted to try -- VHT's epoxy paint. Did a quick sand & clean on the truck's custom bumper and painted it one unseasonably warm afternoon. Turned out pretty nice, think I'll use this stuff for the chassis:



I'm using those 3M stripping wheels attached to the end of a cheap ol' drill to strip off the paint and the little bit of rust I've found. The truck's white color isn't original; I love original stuff, but the truck's factory color is "piss yellow", so I'm not gonna do that. Most of the metal underneath looks really nice:



Started to get damp at night so I had to do something about the bare metal on the cowl. Got some decent zinc primer on:



More to come...

[Stammer]

Welcome, can't wait to see your progress.

[RobGV]

So this is why the engine was quitting

The first batch of pics were from a week ago. Late last week the truck became a huge priority, so getting it done is my new full-time job.

Got the engine stripped down and into the machine shop in a few hours Saturday. Found out that I've got one of the nice & heavy fully-counterweighted 258 cranks. Also found out why I had started losing cylinders so fast:



In case it's not obvious -- my cam seems to be missing some lobes! Here's a slightly better pic:



No big deal though, right? So long as the lifters are all really really good, that cam'll work fiiiiiiine. What do you think of my lifters?





Exhaust system back to the muffler is completely out, transmission is safely out & on the ground, light coat of primer on most of the cowl & firewall (I ran out), and I'm almost done with the frame rails:



I'm really not looking forward to the bill from the machine shop, but once I get the engine & crank back, it should be ready for paint & assembly.

[Dumpy]

Awesome! I love my 72. I have the same yellow, too!

[3rdelement]

so far i like it

[bruner1981jpce]

Awesome work. Can't wait to see more

[jaber]

Well, I still have to give you the customary "welcome to the land of empty pockets and unfinished projects". Its just the way I am...

Its looking great so far. I'll be watching for more pics.

[RobGV]

I'm finally getting back to work on 'er, just got some parts back from the sandblaster and ran into a little problem. Hoping somebody can help me figure this out.

The transmission cross-member is cracked pretty badly, both sides, through the folds and around the mounting holes. I'd consider welding up one crack, but this thing looks like it's done.

The trick is that the truck came with a different transmission from stock. The guys at Novak think I have a T98 with a Dana 20 transfer case. The cross-member had been modified to fit this setup, but judging by the cracking, I'm thinking the T98 might've been a bit too heavy for it?

I'm out of my depth here. Is there a particular cross-member type I should go looking for? Or weld the ever-loving heck out of this thing and hope it stays put? I can post photos if it'll help.

[44BZ]

I'm no expert, but I don't think the crossmembers changed much over the years. I have a T18/T98 in my truck too so although it may not have been original to your truck, I don't think there would need to be much modification to the crossmember to make it work. Pics could help, but someone would probably be able to come up with a decent crossmember for you...

[RobGV]

Alright...





I kinda read it as the PO cut the two center holes, changed his mind and welded in a plate to fix it, but there's still the additional cut on the side. There was a home-made (farm-made ... yeah, one of those) cross-brace that mounted between the cross-member and the transfer case. My best guess is he was trying to reduce side-to-side stress on the transfer case mount.

The cracking still seems unusual to me though (lighting wasn't good enough to capture that), and I can't figure a way that it would be related to the original modification. They look like stress fractures.

edit: fixed photo sizes.

[Rod2]

I've had to have my x-member, which looks exactly like yours did originally, straightened and welded up twice because of trail rash. Ears for bolts into the frame rail are especially susceptable to stress fracture. I used extra thick washers welded in the ear area for reinforcement.
I have no idea what the notch in the channel is for; clearance for a non-stock drain plug?
Mine is a stock T-18/D20 combo.
So, yes, weld away and make it fit whatever tranny you have to put in it.

[44BZ]

Mine was also in similar shape when it came out for new mounts and hardware. A PO had drilled new holes, but did it wrong and the holes got hogged out so the tranny mount was actually sliding back and forth. I welded a piece of steel to the under side and drilled new holes, installed a new rubber mount, and seems to be good as new

[RobGV]

Awesome, thanks for the advice. Picked up the stuff I need today. Gonna try to get this part knocked out quick since it'll want to rust fast. (I didn't notice the cracks until after the metalprep had gone on.)

[Dumpy]

Progress keep it up!