1983 G20 van build - looking for advice

[kv1]

Thank you cripple, BabyDiesel and 200mc for all the continuing help and information. From what I understand I don't need a transfer case then. Please correct me if I'm wrong after seeing this post.

Here are pictures of the original transmission. I see MD8 stamped onto it. I hope it's not a 700r4 cuz now I have two lol, when I could've kept the old one. The old trans feels like a 3speed though, I don't know. Anyway, old trans:



Chart that contains info on transmissions and powerplants for pickups made in that era, not sure if applicable to G20.


New trans after cleaned by Irving:



Is the new (used) trans better than the old trans? Does it need any sort of modification before it replaces the old one? What model is the old transmission? Sorry about asking stupid questions... I just don't have any prior experience in cars, and this will be my first car after it's up and running.

A new battery tray Irving got me:


Not sure what this is:


Oil pan before/after cleaned by Irving:



Irving is going through the diesel engine and replacing gaskets and checking if things are okay. He is optimistic about the condition of the engine. He said:
"Still no visible cracks on block or signs of bad maintance. I replaced the
oil pan gasket and straightened it out as it was a little dented. Leaving
as is will not get good oil flow throughout upper valvetrain."






"Thats the bottom of the piston. Pic taken from under block with oil pan removed":

[spacemanspif]

MD8 denotes 1989+ 700s.
TH-700R4 Transmission Identification

[kv1]

oops! wow I feel stupid. The 305 that was in there felt like it was revving soo high when I was driving on the freeway though, at least 3500k.

Which transmission should I keep then?

[kv1]

Why are the bellhousings different? The original one has a D and the one I bought has a K. Which one should I keep?

[spacemanspif]

Originally Posted by kv1

Which one should I keep?

Both. If they are both 700s then they will interchange without needed to change driveshaft or anything else. It's always good to have a spare laying around. Save up your pennies once the swap is done and have the spare rebuilt once you are sure both are 700s. Should cost around $500 since they don't have to pull the trans out of the van.

this link shows the pan gaskets of the popular trannies and is the easiest way to determine what trans you have.
http://www.nastyz28.com/chevy-transm...tification.php

[kv1]

Hello guys and gals,

Sorry; I've been out of touch for a while. The next three weeks are going to be hard for me as the quarter is coming to an end.

I ended up selling the old transmission (sorry I went against your advice, spacemanspif). I needed the cash to pay Irving. I saw a couple 700r4s on sale for 700$ already rebuilt, so I think I'll just get another rebuilt one when the time comes. Currently waiting on my paycheck to arrive so I can spend a little bit more to finish the van (parts like the radiator, water pump, starter, alternator, wiring, etc). Btw that pan gasket link is super useful haha, it's ingenious to identify transmissions that way.

Irving put in the engine onto the mounts from the looks of it:


He also has a question about the flywheel. He says that it can't handle the torque of the starter. This does not make sense to me as the flywheel came with the engine. What do you guys think?

[mos.eco.gee]

Hello Ladies & Gentlemen!! I got a question in which i need some advice. Do i need to replace the flywheel from a 5.7 to a flywheel from the 6.2? I will be using a Heavy-Duty Starter. My concern is the high torque input will damage the teeth on the flywheel or make it give out prematurely.

[kv1]

My bad, no flexplate/flywheel came with the 6.2L engine. (flexplates are flywheels for automatic transmissions from what I read)

What flexplate do I need to match the engine to the 700r4 transmission? The flexplate from the 305 motor is not going to work obviously.

I found that 700r4 come standard on GMC-Jimmys made in 1982 onwards, and I know that some shipped with the 6.2L motors.

So I went to this kickass site:
1983 GMC JIMMY Flexplate



I really hope I'm onto something. Will this flexplate work? Since the engine and trans are the same as mine?

@Irving/mos.eco.gee can you please verify the transmission (http://www.nastyz28.com/chevy-transm...tification.php) that it's the same one as THM700-R4/4L60/MD8. If that's the case then that flexplate will work, and if it's only 40 dollars I can get it this week.

[Gasoline Fumes]

I have a used 6.2L flexplate from my 1983 GMC Pickup. I can probably be convinced to sell it, I'll never use it again.

[kv1]

Found a new one from amazon for 45 bucks, cheaper than rockauto because of freeshipping.




I'd love to buy yours GasolineFumes, better for the environment to use used goods. Any reason not to buy a used one? They don't wear out do they? Is yours usable with a 700r4 transmission?