Lets build a Transmission

Any of you guys dabble into transmissions here? I got over excited one day installing my trans and broke the bellhousing, so now I have to change the entire case. I figured now was the time to throw some more performance stuff at it. I have a few questions on what I got to do to get it to stay together because I'm going to beat on it lol.

What transmission, C6? I have built a few, C4, FMX, E4OD, AOD, C6 and even a 2 speed Ford-O-Matic.

85lebaront2 wrote

What transmission, C6? I have built a few, C4, FMX, E4OD, AOD, C6 and even a 2 speed Ford-O-Matic.

Yes sir, C6.

I'm going to be putting 500hp through it and possibly a 150 shot of spray on top. So far I have an external filter and cooler, deep pan, shift kit, S code servo, pink band modulator and a 10" billet 3k stall converter. Shifted nice and firm and never gave me any issues with the stock converter in it.

My spare case had an L servo and an E apply lever that I thought about using. Seems to be everyones going with a Lincoln drum/extra clutch pack, an R code servo, steel rollerized planetary gears w/ an E4OD gear ratio, adjustable modulator, putting a check ball in the governor and putting a wider band in it.

It's going to spend most of its time on the street with some drag racing but I am going to beat on it as well. I want it to hold together and I have no issue spending money on quality parts.

Just not sure what direction to go in and maybe a few other things that would be good for it. I'd like to hear it from someone that's been around it. Tips/tricks/things to watch out for.

A couple of things to look at, wide Kevlar 2nd gear band, extra clutch discs in the forward and reverse/high clutch. There are different ratio 2nd apply levers which are used to increase/decrease the load applied to the band. Governors, there are lots of different governors for the C6 and different weights and springs also. See if you can find a parts list for a 1967 Shelby GT500, they had a 428 PI short block with a 427 medium riser top end (dual 600 cfm Holleys). That was an engine with a lot of torque low down even with the PI cam.

The other thing would be to look into any diesel application for clutch packs and band as they are low end torque engines also. 1966-68 Lincoln 462 as it was the old MEL block (case won't fit as it is an FE bolt pattern) but they were torquey engines too, the 1958 430 was 375 hp @ 4800 rpm and 490 ft-lbs torque @ 3100 rpm. The 462 was 340 hp net and 485 ft-lbs. They used a special large case Cruise-O-Matic with an spacer between the back of the case and the extension housing, later ones had a special case with the band servos cast into it.

85lebaront2 wrote

A couple of things to look at, wide Kevlar 2nd gear band, extra clutch discs in the forward and reverse/high clutch. There are different ratio 2nd apply levers which are used to increase/decrease the load applied to the band. Governors, there are lots of different governors for the C6 and different weights and springs also. See if you can find a parts list for a 1967 Shelby GT500, they had a 428 PI short block with a 427 medium riser top end (dual 600 cfm Holleys). That was an engine with a lot of torque low down even with the PI cam.

The other thing would be to look into any diesel application for clutch packs and band as they are low end torque engines also. 1966-68 Lincoln 462 as it was the old MEL block (case won't fit as it is an FE bolt pattern) but they were torquey engines too, the 1958 430 was 375 hp @ 4800 rpm and 490 ft-lbs torque @ 3100 rpm. The 462 was 340 hp net and 485 ft-lbs. They used a special large case Cruise-O-Matic with an spacer between the back of the case and the extension housing, later ones had a special case with the band servos cast into it.

I've been told to stay away from Kevlar actually by quite a few people. What's your reason for going with Kevlar over a standard band? Extra clutch packs for sure would be an upgrade no doubt there.

I'm under the impression the apply lever from the Torino case is probably actually better than what's actually in my truck right now but I won't know for sure until I get in there. All I know that's done to my trans in the truck is what I listed.

Looking into diesel stuff wouldn't be a bad idea either. I'm expecting this engine to be pretty smooth in torque production with a pretty flat curve, staying right around 500-525 lb-ft from 2000 rpm right up to 5500.

The spare case I had actually looked pretty good inside, but I decided to tear it apart anyway because something was messed up and would not go through the gears manually.

I used a Kevlar band in my original built A413 (Mopar FWD transaxle). and had no issues. If there are better friction materials available, great. Biggest thing is look at the width of the band and the lever ratio along with the size apply servo. I haven't built a performance C6, but back in the middle to late 60s built a C4 for a 1964 Falcon with a bad case of snakebite (260, Jahns 10.5:1 pistons, Lunati hydraulic cam, 3 Holley 2 barrels on it. It would chirp the tires on the 1-2 shift, and 2-3 was right now, no slip. Had to use thin friction discs to increase the number. Old guy in Virginia Beach helped me build it, I made a case girdle (good idea for your C6) to stiffen the case and increase the capacity.

If you are going to have a high stall converter, add plenty of cooling, almost all the heat in an automatic comes from the converter (why I like a lockup one for my street cars). An old AC condenser, not one of the newer multipass ones works quite well.

85lebaront2 wrote

I used a Kevlar band in my original built A413 (Mopar FWD transaxle). and had no issues. If there are better friction materials available, great. Biggest thing is look at the width of the band and the lever ratio along with the size apply servo. I haven't built a performance C6, but back in the middle to late 60s built a C4 for a 1964 Falcon with a bad case of snakebite (260, Jahns 10.5:1 pistons, Lunati hydraulic cam, 3 Holley 2 barrels on it. It would chirp the tires on the 1-2 shift, and 2-3 was right now, no slip. Had to use thin friction discs to increase the number. Old guy in Virginia Beach helped me build it, I made a case girdle (good idea for your C6) to stiffen the case and increase the capacity.

If you are going to have a high stall converter, add plenty of cooling, almost all the heat in an automatic comes from the converter (why I like a lockup one for my street cars). An old AC condenser, not one of the newer multipass ones works quite well.

Do they make girdles for C6's anymore? I had a friend tell me that the pan I have on it being heavy cast aluminum helps really stiffen up the case of the trans itself. I don't mind nice firm shifts. Quicker the better. The shifting in the trans currently is a real quick 1-2 that you can feel real nicely, no chirping unless its wide open. 2-3 is definitely a right now thing as well. I have some videos of it going down the road, it definitely would toss your head back.


Yes I have a B&M super cooler plumbed in front of the radiator. I want to put a trans temp gauge in to monitor heat, if I have to I'll move the cooler and put a fan in front of it.

The pan does help, the girdle was maybe 1/2", if anyone makes them it would probably be B&M or similar.

Angelo, you’ve probably heard of them but I’ve been looking at a lot of C6 parts lately and Broader performance seems to be the way to go. They’ve got everything from wide ratio gear-sets, to valve bodies, to rebuild kits, and complete transmissions good up to 750 horse. When I redo mine I’m giving them a call. Rusty has been in contact with him and posted a bunch on a different thread I started, I’ll try to link it here soon if it would help. I can’t give too much tech advice but I’m looking forward to what you do. I’ve got a similar plan with mine, wide ratio set, good rebuild kit, quality converter and valve body, most of it from Broader if that’s the way it works out. They might be good to call, they are a Ford only place.

85lebaront2 wrote

The pan does help, the girdle was maybe 1/2", if anyone makes them it would probably be B&M or similar.

I'll have to check it out. I don't have a problem putting one in.

Jacob84 wrote

Angelo, you’ve probably heard of them but I’ve been looking at a lot of C6 parts lately and Broader performance seems to be the way to go. They’ve got everything from wide ratio gear-sets, to valve bodies, to rebuild kits, and complete transmissions good up to 750 horse. When I redo mine I’m giving them a call. Rusty has been in contact with him and posted a bunch on a different thread I started, I’ll try to link it here soon if it would help. I can’t give too much tech advice but I’m looking forward to what you do. I’ve got a similar plan with mine, wide ratio set, good rebuild kit, quality converter and valve body, most of it from Broader if that’s the way it works out. They might be good to call, they are a Ford only place.

I have a local trans shop that deals with Fords pretty exclusively; Competition Transmission. They deal pretty worldwide which is cool; they built my converter. I'll keep you in the loop. The truck is pretty stout overall.