GoFastBroncos.com

Were looking for feed back on are C-6 trans and 4.11 gears. Bronco has the 400m seems to work okay. We keep Lucas oil stabilizer in it . For the tran we know we need to beef it up.we installed big trans cooler with back up w/ fan. Thinking about adding manual valve body . Any thoughts? Also seem to run second gear most of the time. Was thinking about changing to 4:88 or 4:56's.. Thanks

You don't say here what tire size you are using but I would recommend 4:56 for 33" tires and 4:88 for 35" tires. Used a basically stock trans for one race and it did not like it very well. Going to needle roller thrust bearings helped as well as opening up the cooling circuit flow. A manual valve body won't help with trans life but does improve the drivability. You do end up running in second gear a LOT, just the way it is.

I have the E4OD wide ratio gears, big R-Servo piston and TCI reverse manual shift, TCI torque and shifting is OK. Since I went to 37 the 4:10 gears are really not enough. I just finished my 5:13 gears. Should be putting them in after this winter. I’m sure this will revive the truck!
Also, what I have found with my C6 is that you need a lot of cooling capacity? This might be a result from the torque converter change? I did install a big cooler with an auxiliary fan. This now keeps the temps under 180 at all times.
Please post you’re built. There is not enough 78-79 posting.

You will need a lot of cooler for any auto if you are going to run hard off road. My experience,even without a loose converter, is that you need a lot bigger than what they sell them in the GVWR range in the standard catalogs. The generic 20,000 lb motorhome unit is not enough. Then put a gage on it and if it runs over 220 figure out why and fix it. The fan assisted units should help but you are adding more electric loads and things to break.

cdnbronco wrote:I have the E4OD wide ratio gears, big R-Servo piston and TCI reverse manual shift, TCI torque and shifting is OK. Since I went to 37 the 4:10 gears are really not enough. I just finished my 5:13 gears. Should be putting them in after this winter. I’m sure this will revive the truck!
Also, what I have found with my C6 is that you need a lot of cooling capacity? This might be a result from the torque converter change? I did install a big cooler with an auxiliary fan. This now keeps the temps under 180 at all times.
Please post you’re built. There is not enough 78-79 posting.

E4OD has steel forward planet gear with 6 pinion gears ?

Running in 2nd gear all the time will burn up the transmission. Put in lower gears and use drive.

After 30,000 race miles and nearly half of that in second gear, I can safely say that what will burn up a C6 transmission is slippage, a plugged filter, or insufficient cooling. Even the standard aluminum housing planetary with 3 planet gears and stock input shaft holds up, at least with something south of 400 hp.

"After 30,000 race miles and nearly half of that in second gear, I can safely say that what will burn up a C6 transmission is slippage, a plugged filter, or insufficient cooling. Even the standard aluminum housing planetary with 3 planet gears and stock input shaft holds up, at least with something south of 400 hp."

Great info, thank you!