[jdalley69]

Ok first of off you guys are really helpful and have pretty much been dead on on previous posts. second of all I been drinking and my typing may be in typoenese some....

OK I have a C-4 transmission with a 84 302 5.0 L engine in a 66 mustang. I recently got this as a running project while my other long winded project is being worked on some since Im not a welder. I been nit picking this 66 I have had for about 3 weeks now. I have notice that the kick down linkage is not connected while I been driving it. I asked a friend who has a 302 in his old bronco is this normal he said yes and no...He said he heard if there is OD in a vechile that if the kick down linkage is connected it could mess something up? im not sure what he meant though.

Anyone else have some ideas why it would not be connected? Or should or shouldnt be? I was told the transmission C-4 was original but I really dont know?

Thanks Guys and Gals....please takl to me in a language that I know nothing cause I dont when it comes to trannies...

[johnny rotten]

if it is a c4 then you have no passing gear or kick down. on a overdrive that lever is throttle pressure and your trans won't last long or shift properly.why it's not there is anybodys guess.you can achieve a kick down with modulator if you hit it hard enough or pull it in second manually.

[jdalley69]

I honestly do not know if it is a C-4 or C-6 Just that the person I bought it off of said it was a C-4? I really do not know to be honest. It is a automatic also forgot to put that. There is just a lever/linkage when looking in at the engine from the front I can just see it hanging there right uner the driver side it looks like. This is what he put to an email to me:

1984 302 Lincoln LSC Mark Series Coupe
1984 Bell Housing 1984 Mustang
Original c4 trans

[bubbamace]

Originally Posted by jdalley69

Ok first of off you guys are really helpful and have pretty much been dead on on previous posts. second of all I been drinking and my typing may be in typoenese some....

OK I have a C-4 transmission with a 84 302 5.0 L engine in a 66 mustang. I recently got this as a running project while my other long winded project is being worked on some since Im not a welder. I been nit picking this 66 I have had for about 3 weeks now. I have notice that the kick down linkage is not connected while I been driving it. I asked a friend who has a 302 in his old bronco is this normal he said yes and no...He said he heard if there is OD in a vechile that if the kick down linkage is connected it could mess something up? im not sure what he meant though.

Anyone else have some ideas why it would not be connected? Or should or shouldnt be? I was told the transmission C-4 was original but I really dont know?

Thanks Guys and Gals....please takl to me in a language that I know nothing cause I dont when it comes to trannies...

The original C-4 on my 66 mustang had a kickdown cable from the trans to the carb linkage. I changed my original shift linkage to a Hurst shifter, which no longer uses the cable and required my to saw off the original linkage on the C-4. The C-4 is a three speed transmission and should kick down when you press down hard on the accelerator. If it is an OD (overdrive trans) then it should have four gears and a cable that varies the pressure in the trans. If the cable is missing or not adjusted properly on an OD trans, it will eventually cause damage to the transmission.A C-6 is also a three speed transmission. As far as I know, its just a stronger version of the C-4. Someone correct me if I'm wrong on the C-4 versus the C-6

[sav_syn_sptz]

c6 is one complete piece and the c4 comes apart by the housing i am told and weights alot less because of it... thats what ive been told

will it mess the tranny up to manually shift? havent had mine hooked up do to when i changed my carb that pos bar was bent and wouldnt reach and the apapter piece doesnt work keeps it in low gear

sorry for jacking the thread

[Chelle C]

If the linkage is hanging on there hooked up at the carb. Why not connect it at the transmission and see if it is working? The C clip may have fell off, it could be something as simple as that. Another thing that transmission could have been changed out from C6 to a C4 and the linkage may no fit, in shich case you would have to get another piece of linkage. I have made linkage in the past by using a piece of 1/4 in stock. Use a welding rod to make a template so you get your bends right and heat it and bend it as necessary. I used a couple of adjustable rod end bearings on mine so I could adjust it. A quick way to identify the C6, C4, and FMX. The C4 has a square pan and is a two piece meaning the bell housing will bolt on and off of the transmission housing. The Pan on the C6 is square on three sides and has one corner that is notched. It is also a single piece transmission meaning that the bell housing and transmission housing are all one piece. Both the C6 and C4 are all aluninum. The FMX is a cast iron transmission and has seperate bell hounsing and transmission.

[bubbamace]

Originally Posted by sav_syn_sptz

c6 is one complete piece and the c4 comes apart by the housing i am told and weights alot less because of it... thats what ive been told

will it mess the tranny up to manually shift? havent had mine hooked up do to when i changed my carb that pos bar was bent and wouldnt reach and the apapter piece doesnt work keeps it in low gear

sorry for jacking the thread

One of the reasons I kept the C-4 is, I was told that the C-4 is lighter and could be built to handle as much horsepower as I was shooting for (500 horsepower). As far as the linkage, I'm not sure if the loss of the cable, etc will harm the trans. I don't think so, but I know for sure it will on the AOD. I'd either fix the pieces you have, buy new pieces out of a catalog of get a Hurst shift linkage that does away with the stock system. I don't like having trouble with transmissions because its one of the parts of the car I don't repair. Everything else I enjoy doing.

[Chelle C]

Originally Posted by bubbamace

One of the reasons I kept the C-4 is, I was told that the C-4 is lighter and could be built to handle as much horsepower as I was shooting for (500 horsepower). As far as the linkage, I'm not sure if the loss of the cable, etc will harm the trans. I don't think so, but I know for sure it will on the AOD. I'd either fix the pieces you have, buy new pieces out of a catalog of get a Hurst shift linkage that does away with the stock system. I don't like having trouble with transmissions because its one of the parts of the car I don't repair. Everything else I enjoy doing.

If you are shooting for 500 HP, I would certainly go with the C-6. The C6 is a lot stronger tranny than the C4. I had a C6 in a Ford pick up with a 429 in it and it was producing 500 HP and it was a strain for the C6. I eventually burned it up and had to rebuild it. What they kind of HP you will certainly have failure with a C 4. The reason it is lighter is because it is not as much transmission. The C4 trannys was used on the cars with smaller or less HP engines. Another alternative that many people over look is the FMX. They never really gained popularity partly because they were cast iron and many people thought they were to heavy also there was not a lot of performance parts made for them either. But by the same token they were nearly indestructible.

[bubbamace]

Originally Posted by Chelle C

If you are shooting for 500 HP, I would certainly go with the C-6. The C6 is a lot stronger tranny than the C4. I had a C6 in a Ford pick up with a 429 in it and it was producing 500 HP and it was a strain for the C6. I eventually burned it up and had to rebuild it. What they kind of HP you will certainly have failure with a C 4. The reason it is lighter is because it is not as much transmission. The C4 trannys was used on the cars with smaller or less HP engines. Another alternative that many people over look is the FMX. They never really gained popularity partly because they were cast iron and many people thought they were to heavy also there was not a lot of performance parts made for them either. But by the same token they were nearly indestructible.

I guess what I should've said was when I was building my engine and shooting for 500 horsepower, which I achieved, I had my C-4 professionally built. The C-4 I have has no problems handling that much horsepower, but it cost me a few bucks since I don't work on transmissions.

[Chelle C]

Originally Posted by bubbamace

I guess what I should've said was when I was building my engine and shooting for 500 horsepower, which I achieved, I had my C-4 professionally built. The C-4 I have has no problems handling that much horsepower, but it cost me a few bucks since I don't work on transmissions.

Glad you have had good luck with it, I guess only time will tell. The old 429 may have been putting out a few more ponies than 500 HP, and it certainly some substantial torque. The same engine later split a C6 case right down the middle drag racing one night. I had to have the guy I was racing tow me home. I was just always one that tried to build them as bullet proof as possible the first time around. It seemed to cost less in the long run. Hopefully you will get many trouble free hours out of your tranny.

[The Greek]

There should be an arm extending down from the accelerator pedal linkage just beyond where it goes through the firewall. The downshift cable attaches to this arm. If it's a pedal assy. from a standard shift car, it won't have this arm.

If the arm is there, to adjust the cable, you want the pedal to the floor and the downshift lever pulled all of the way forward. Adjust all of the slack out of the cable to where the threaded piece (Trunion) will line up to the hole in the arm. Once the hole matches up, turn the threaded piece one more complete turn tighter and install.

You can get away with not having the kickdown hooked up with the C4, but you won't have the kickdown activate like it should. I know you didn't mention any HP, but the C4 when built for V8 specs should handle a 300 hp engine. They can be upgraded to handle as much as 1000 HP if you have the money.

There is no need to worry about finding a C6. You don't need it. They weren't used on production small block Mustangs in 66 only the C4 was used.

[bubbamace]

Originally Posted by Chelle C

Glad you have had good luck with it, I guess only time will tell. The old 429 may have been putting out a few more ponies than 500 HP, and it certainly some substantial torque. The same engine later split a C6 case right down the middle drag racing one night. I had to have the guy I was racing tow me home. I was just always one that tried to build them as bullet proof as possible the first time around. It seemed to cost less in the long run. Hopefully you will get many trouble free hours out of your tranny.

Thanks for the information. Next time I build one, I'll look into the C-6.

[Aceport]

HI every one, I have a 1970 mustang coupe 351c with a fmx trans i think.what is going on is when i'm at a dead stop and hit the gas my shifter drops down in to second gear its a automatic do i need to adjust the linkage or what? or does the old trans do this i think its not right, if any one can help that would be great

[PaulS]

You need to replace the broken mount(s) on the engine and/or transmission.

[PaulS]

The C4 has been built to handle over 1000HP.
The C4 case is inherently stronger than the C6 case. (they do have a pan girdle to strengthen it)
The C4 is being used in many cars with 429 and 460 engines and there is an aftermarket company that is building bells for the big engines and the C4.
The C6 internals are stronger versions of the C4 with the C4 reverse band replaced with clutches that anchor in the aluminum case. The weak point in the C6 is that big pan opening. I have seen many C6 cases broken - many more than C4 cases even when running the same power.
Both are excellent transmissions when properly prepared for the power put in front of them.