Trans and gear ratio's ?

Smith racing
Posts: 140
Joined: Sun Apr 14, 2013 8:49 am
Bronco Info: 1978 bronco class 3 and 8 smith racing was inspired from Moss Brothers

Trans and gear ratio's ?

Post by Smith racing »

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
Attachments
image.jpg
image.jpg (85.94 KiB) Viewed 4279 times
300
Posts: 647
Joined: Tue Jan 26, 2010 4:44 pm
Bronco Info: 1979 Class 3 Race Bronco. Built in 2000.

Re: Trans and gear ratio's ?

Post by 300 »

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.
cdnbronco
Posts: 79
Joined: Fri Nov 19, 2010 5:38 pm
Bronco Info: 1978 bronco, 3 link front, 4 link rear, fully caged, 460 engine, custom fiberglass,

Re: Trans and gear ratio's ?

Post by cdnbronco »

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.
300
Posts: 647
Joined: Tue Jan 26, 2010 4:44 pm
Bronco Info: 1979 Class 3 Race Bronco. Built in 2000.

Re: Trans and gear ratio's ?

Post by 300 »

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.
BigCrunch
Posts: 11
Joined: Sat Jan 03, 2015 11:20 am
Bronco Info: 1978 Bronco Custom

Re: Trans and gear ratio's ?

Post by BigCrunch »

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 ?
User avatar
Phoenix0783
Posts: 658
Joined: Thu Dec 10, 2009 12:50 pm
Bronco Info: No more Bronco :(
Location: Bend, OR
Contact:

Re: Trans and gear ratio's ?

Post by Phoenix0783 »

Running in 2nd gear all the time will burn up the transmission. Put in lower gears and use drive.
300
Posts: 647
Joined: Tue Jan 26, 2010 4:44 pm
Bronco Info: 1979 Class 3 Race Bronco. Built in 2000.

Re: Trans and gear ratio's ?

Post by 300 »

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.
User avatar
Hauls Assington
Posts: 295
Joined: Wed Oct 23, 2013 5:44 pm
Bronco Info: Under Construction
Location: Las Cruces , NM

Re: Trans and gear ratio's ?

Post by Hauls Assington »

"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!
Post Reply