The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Auto Trans swap in 72 GMC

**MidLifer** · 02-18-2014, 07:27 PM

The 700r4 electronics are not such a big deal - TCI sells the kits, and a good trans builder can set it up so that all you need to do is mod the brake light switch to disengage the tc lockup when you step on the brakes. Alternatively you can put a toggle switch on the dash and manually engage and disengage lockup.

The other trick with the 700r4 is the TV cable, which is NOT a kickdown cable and must be properly adjusted or you will meet with rapid disaster. Again, not a hard thing to do, but you will need the right bracket for your carb. They are widely available online. Bowtie Overdrives has great info on their site about this. Check out their TV Made EZ kits.

If you want to drive at modern highway speeds, the OD is a big plus and your gas mileage will improve significantly. If you are just doing around town driving, the TH350 should be fine unless you are consistently hauling a ton in the bed or towing something huge.

02-18-2014, 07:27 PM	#8
MidLifer Senior Member Join Date: Apr 2011 Location: South NJ Posts: 1,269	Re: Auto Trans swap in 72 GMC - Need Help The 700r4 electronics are not such a big deal - TCI sells the kits, and a good trans builder can set it up so that all you need to do is mod the brake light switch to disengage the tc lockup when you step on the brakes. Alternatively you can put a toggle switch on the dash and manually engage and disengage lockup. The other trick with the 700r4 is the TV cable, which is NOT a kickdown cable and must be properly adjusted or you will meet with rapid disaster. Again, not a hard thing to do, but you will need the right bracket for your carb. They are widely available online. Bowtie Overdrives has great info on their site about this. Check out their TV Made EZ kits. If you want to drive at modern highway speeds, the OD is a big plus and your gas mileage will improve significantly. If you are just doing around town driving, the TH350 should be fine unless you are consistently hauling a ton in the bed or towing something huge.