'74 J20 with a GM drivetrain 4.3L/700R4/NP208

[sgtpoliteness]

It was the t-stat, I knew it!! *highfivemyself*

Good thing you got heat with this cold!

[AwesomeJ10]

Been daily driving the J20 for the past few days. Drove it down to Denver a couple of times and once up into the hills. I think it's getting around 16-18mpg Everything is working great. It's the ONLY jeep I've ever had (past or present) where the heater/headlights don't go dim at idle. The chevy alternator has a little more juice than a standard FSJ alternator.

The 700R4 is going out and the 4th gear is slipping on the HWY after about 40 miles. Everything I'm reading says the 4th gear clutch pack are weak and need replaced. The local AAMCO wants $1000 to rebuild it with no warranty (that's with me bringing the tranny to them). $1400 with a warranty. Rebuilt kit costs ~$200, so I guess I'll be learning how to build a 700R4 soon...

[lindel]

It's not that hard really. http://www.transmissioncenter.net/ That's a decent resource for info, and some parts. A local transmission supply house can be a good resource too. The tools you need to rebuild one are the bigger issue, but with good fab skills (I think you're good there!) and you can rig up your own tools.

[66stepside]

Whew, found it.

Now that it's all dialed in, if you had a "do over" button, would you have done anything differently with the build?

[AwesomeJ10]

Whew, found it.

Now that it's all dialed in, if you had a "do over" button, would you have done anything differently with the build?

yeah... well, this motor and tranny have over 150k miles on em. the tranny is still slipping badly and I can only drive 10 miles or so before it starts slipping 4th gear. the motor is leaking oil out the passenger side cylinder head (not valve cover, the head is leaking..)

but I do DD this thing.

It needs a major tune up. I'll probably swap another cheap v6 and hopefully a better tranny...

[rocklaurence]

Very cool build but I noticed you didnt elaborate much on the wiring part--how hard was it? I like your thinking in regard to expensive tranny rebuild. Ill do it myself--my roof, cars, plumbing etc.

[AwesomeJ10]

Wiring...I essentially have three wiring harnesses;

stock tbi/motor harness that came with the 4.3l v6

stock engine/lights/dash wiring from an '89 GW. This allows me to run the stock '74 J20 instrument cluster, but still have 'modern' atc fuses and intermittent wipers (also have '89 GW steering column and wiper motor)

stock rear wiring harness for the tail lights.

So I ended up spending a lot of time on this site: http://oljeep.com/gw/elec/GW_wiring.html looking at wiring diagrams. very, very time consuming, but not 'hard'.