I am going to add a trans cooler to the 76 as the C4 is heating up pretty bad and suspect that the stock radiator/trans cooler might be restricted or blocked. Either way It will be good insurance.

I plan on adding a plate cooler to the passenger side near the in/out ports on the trans near the frame rail. question I have is shoudl I add it to the return line or the send line? Anyone know what the fittings are? is anyone using barbed fittings or AN?

EDIT: is this correct? found this from Vipers post on CB.com

5/16" inv (1/2"-20) x -6
Aeroquip
#FCM2111
about $7ea

Those fittings above adapt to the factory inverted flare fittings in the trans. WH has a set that will replace the factory fittings. It looks like they took a pipe thread and cut the taper out. http://www.wildhorses4x4.com/product/C4 ... ittingPAIR The thread in the C4 case is a straight (non-tapered) pipe thread. Use tapered pipe thread there and you'll crack the case.

I'm sure the stock cooler isn't completely blocked or you would have burnt up the trans pretty quickly. The return oil lubes the entire rear half of the transmission. Trans cooler should be on the cold side of the radiator. Some aftermarket reverse flow radiators don't do this and they are worthless. Higher coolant temps of EFI motors will cause the cooler to be less effective though.

There isn't a lot of airflow underneath so I would put the additional cooler in the return line. My thinking is the new cooler won't be real effective but it may drop the temps 10-20 degrees like that. On the hot side you can't drop temps much because the radiator cooler will bring them back up with the coolant temp.

I have 2 set's of those fittings too if you need a pair.

Maybe just put a cooler with a fan under the truck and eliminate using the radiator.

I thought about the fan but honestly I don't want to add any wiring :)

I've had terrible luck with two different coolers in front. Tube And plate style. Runs hot too. I'm going to remote mount a derale 13900 over the rear axle. I think the radiator heat soaks the coolers .02