TH350 to 700R4 Easy swap???

[kelsfine69]

Ok

We got the old 72 up and running and reverse is kinda iffy...So now is the question...Do we pull it out and send it in for a rebuild or....I found a used 700R4 on Kijiji for cheap and recently rebuilt. Is it a hard conversion? What is involved? Do I need a new tailshaft and get the driveshaft custom made using the old one? im sure the crossmember needs to be moved and holes redrilled but how do you do the top ones with the cab on?

[Bpokey]

I put a 2004r in mine. You can build a 2004r to take just about anything you can throw at it. I have a friend with a 67 firebird that has a built 468 Pontiac and a 2004r. The 2004r has more overdrive, better gear ratios and takes less power to turn than a 700r4. The swap is easier because if you have a TH350 you don't need a new driveshaft and you can use the crossmember you have and just move it to the TH400 holes in the frame. I just did this to my 68 and it was easy. I got the trans and converter from a junkyard for $100 and I have less than $200 in the swap. Be sure to get a Stator shaft with hardened splines, they are easy to change and I found one for $13 at www.makcotransmissionparts.com. You will also have to bend the cooling lines a little.

[Hoffman65burb]

correct me if im wrong... but i was talking to the guy at the local lordco, he was saying dont put a 700R4 unless its in a computer operating car/truck, apparently it will sometimes do crazy stuff like shift into 3rd going around a corner at 20mph

[kelsfine69]

What did the 2004rs come in. Do they have a tv and a lockup

[MonteSS454]

Originally Posted by Hoffman65burb

correct me if im wrong... but i was talking to the guy at the local lordco, he was saying dont put a 700R4 unless its in a computer operating car/truck, apparently it will sometimes do crazy stuff like shift into 3rd going around a corner at 20mph

I think you may be talking about the 4L60E which all it is is a computer controlled 700r4. I have a 700r4 in mine and don't have that problem and my lockup is tapped in to an ignition wire.

[Bpokey]

2004r's came in all kinds of GM cars from 1981 to 1990. These are the transmissions that came in the Buick Grand Nationals and Monte Carlo SS. These are the best to get because of the valve body, servo and governor. They also came in all kinds of other GM cars, in fact I got mine from a 1989 Cadillac Deville because the GN and SS ones are scarce. Art Carr builds these and there is an article on Car Craft website on how to build them. They are just like a 700r4 with a TV cable and a lockup converter, so if you are running a carb you will need the cable bracket and the geometry correction bracket that bolts to the carb. These are on Ebay or Summit Racing.

[munger]

but a 2004r isnt 4wd or can you make 4wd

[old_blew_72]

you can't make it 4wd

[culp7]

great info here ttt