Build thread for the 72 GMC, finally. Thanks John!

I'm getting close to being able to move this thing, brakes are next, but one strange thing I can't quite figure out is how to handle the seat. It's rather hard to drive on a big orange bucket, but I don't want to spend the money on a real seat yet either, nor do I have a ton of space to store a bench seat from a junkyard, has anyone done this with like a metal folding chair for temporary use? I just need to be able to drive it to the driveway and back.

I am usually not the safety Nazi, since I would be the one doing this with a beer in one hand. BUT. I was tangentially involved in an episode where the initial test drive on the 5 gallon pail was the driver's last drive. Bolt a seat down to the floor please.

As to brake lines, two ways to go. I buy pre-assembled lengths at CarQuest and cut to length then re-flare the end.

The coil tube is a bit cheaper but it involves making the coil straight.  Straighten the whole coil as best as possible. Fix ond end in a vice or other fixed point and shock the other end by applying a sudden force along the length of the tube. It "stretches" the tube a bit and straightens it. Works with MIG wire also when you need thin TIG filler.

NiCop is the nicest tube to work with. But it is twice as expensive as steel lines.

You can go to a scrapyard and harvest NiCop lines from  Volvo and reuse them if you are being Challenge budget minded.  Done it a few times now. Don't know of any other cars that use NiCop from the factory.

Pete

For just driving up and down the driveway, a cinder block works well. Gets your ass off the floor just enough, and is heavy so it won't move around. Granted for a truck you may need a bit more elevation to be able to see. Maybe just knock some wood together and bolt it to the floor at the oEm mounting points?

Agreed with Pete- do not use this for anything other than "yard moves". I once had a seat come unsalted from the floor (rusty floor boards) and had to motor home for 2 hours using the steering wheel to hold me in place.

In reply to volvoclearinghouse (Forum Supporter) :

My point was that this was a "Yard move" ...first ever under its own power.

Throttle stuck, might have been some panic, bucket fell over, down the driveway and down the ravine on other side of road.

Darwin has a sense of humor.

I'm gonna second Nohome here. I've done the bucket thing and when you give it gas and the bucket moves away you don't have much leeway to then stomp on the brake. Also if you do manage to stomp on the brake the bucket moves forward causing a multiplication effect. So zooooom -> delay -> screech! I got it done - I was loading the car onto a flatbed - but it was pretty sketchy. I was younger and even dumber then.

I did a milk crate when I was about 20, in my V8 Pinto.  Never again. Never.

Oh, I'd do another Pinto in a heartbeat....

Hello again.

This sounds like a minor update, and it is, but I learned a thing.

The transmission in this thing is called an MY6. It is also called an A833 when it is installed in Dodge vehicles. It is made by New Process gear. Dodge made it with both standard 1-2-3-4 and 1-2-3-OD, both iron and aluminum cases. Chevy made it with an aluminum case and 1-2-3-OD and a neat bellhousing to match to the diesel 6.2 or the small block. I like it for a street car. The RPM drop is a bit much for a maximum effort ET, but it gives a nice spread for a wide flat torque curve sort of engine.

Chrysler specified 80W-90 fluid.

Chevy specified ATF.

I said WTF.

I reached out to Jamie Passon at Passon Performance, where I bought the rebuild parts years ago. He said use a conventional GL4 80W-90. He's the man, so I did it. I bet that Chevy was using their own fluid (Dextron) for their own reasons, and that NP probably worked with Chrysler when they made it, and the internals from the OD version that Chrysler used and the OD version that Chevy used were probably identical in terms of materials and hardnesses and such.

So I bought some Valvoline, crawled under my nice clean truck with work chinos still on and was putting in the second quart when I read the bottle.

"Designed for use in non-synchronized manual transmissions where GL-4 is specified and for hypoid differentials where GL-5 is specified. Limited slip differentials top off..."

CRAP

So it's GL5 but really kind of sort of GL4. I don't know the difference, chemically, but I know that it means it won't play nice with synchros, but I can get a refund via Amazon for the Valvoline. Summit delivered some Driven 80W-90 GL4 that's actually GL4 and it goes in this week.

StaLube GL4 at Napa is my go to 85w90. Protects yellow metals and it's a good price. 

So this is the worst update. or at least the worst update you can have when you're filling the transmission with fluid.

I bought a one-piece driveshaft that fit right in from a '93 truck, aluminum and nice. apparently though it doesn't engage all the way, because the fluid is now leaking out the tail shaft seal. I guess it's an inch short or something, any recommendations?

Do you mean driveshaft?

Either way. the mopar a833 seals suck. Mine always dripped. If the was any groove or pitting on the yoke, it was worse.

There was a "problem solver" with a redi sleeve at the parts store that really helped. So did a long yoke 

Dusterbd13-michael (Forum Supporter) said:

Do you mean driveshaft?

Either way. the mopar a833 seals suck. Mine always dripped. If the was any groove or pitting on the yoke, it was worse.

There was a "problem solver" with a redi sleeve at the parts store that really helped. So did a long yoke 

Yes, I corrected that. Sorry.

I guess my fear is twofold, I don't know how much it's supposed to engage to provide torque either. I didn't think about a longer yoke, is that a thing? That seems like the easy button here. The tail shaft seal is brand new, though that could mean that I installed it wrong also. It looks like there's a lot of drive shaft sticking out though.

Long yokes are a thing. Especially in gm world. .id have to have measurements to know about wether too little engagement or not. Generally we like about 3-4 inches of yoke engagement inside the seal/tailshaft with mopar. Again,  dunno about gm version if there anything different. 

What I've been told is that the yoke should be 3/4" out from fully bottomed out. That was for a car, but should get you in the ballpark. 

My engagement is about 2", but it seems to bottom around 3 1/2". I'm going to look up the official way to measure the yoke, but I'm guessing it's 5". 

Is it possible that the outer diameter of the yoke is too small?

Like are there multiple output shafts spec'd for that trans?

Robbie (Forum Supporter) said:

Is it possible that the outer diameter of the yoke is too small?

Like are there multiple output shafts spec'd for that trans?

Good thought, but in Chevy world everything matches everything. This is the same yoke in manual transmissions as in automatic transmissions. I pushed a little harder and got it to go in a little further. I am pretty sure that if I buy a new yoke that is 1 in longer, that is 7.5 in, that it will work out.

I just have to check the budget and the u-joint compatibility.

Of course I could just move the engine and transmission back an inch

In reply to tuna55 :

Ummm,  isn't that the most difficult and time consuming solution?

In reply to Dusterbd13-michael (Forum Supporter) :

Yes, but it's slightly cheaper.

Also, weight distribution.

Is it still stupid? I have plenty of firewall clearance.

Depends: time or money? Which do you have more of? 

If the kids are getting involved,  that weighs heavily in favor of moving the engine if they think it sounds like fun.

Dusterbd13-michael (Forum Supporter) said:

Depends: time or money? Which do you have more of? 

If the kids are getting involved,  that weighs heavily in favor of moving the engine if they think it sounds like fun.

My kids are getting involved more and more, which I love. I'll ask them!

There exist another set of holes for the engine mounts already in the frame. I believe they are for six cylinder applications, they are two and a half inches back. The engine and trans will fit two and a half inches back, but then my yoke will be too long. I think I can use the old yoke from the two-piece drive shaft, in that case, but more research is required.

Just drill new holes where you need them.

They make tools to straighten coiled brake line.

Here's proof that I was actually working in the garage, not just measuring and taking pictures

So the deal is that the old style 3 speed transmission mounts to the rails off of the bell, instead of the tailshaft. When I switched to the (slightly) more modern transmission transmission, I added a tubular crossmember to the frame for the traditional mount. I left the old crossmember there, because taking it out is hard, GM rivets and all. I always wanted to remove it anyway, and now that moving the engine and transmission back means it has to move anyway. Here it is:

There are two the little branch pieces that go to the lower frame rail sections.

Those are out, but the upper sections are hard to reach, so before I could get to the rivets the crossmember needed to be cut. I cut through one side, but the blade broke before I finished to cut. Surprisingly, this worked well enough to finish the cut on the one side. New blades on the way.

It's really hard to take pictures of this, and it's also really hard to remove rivets. I did cut the crossmember out, and was able to remove the two upper rivets on the drivers side and get out the remainder. I am really happy that I decided to go down this path, because the amount of room for exhaust just went way up. The crossmember is super thick, too. Just a few pictures of the result.