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-   -   C4 trans went out, swap or rebuild? (

JedCrone May 19th, 2019 05:39 PM

C4 trans went out, swap or rebuild?
I have a 74 F100 with a 351w from a 78 in it and a c4 trans. The transmission just went out. I think it was the front seal as a bunch of fluid came out. My question is, do I rebuild it? Replace with a C4 or C6? Or put a Tremec 5 speed or maybe M5OD in it? I've wanted to do a 5 speed swap for a while.

Thanks for the help/opinions.

harrison28 May 20th, 2019 08:56 AM

I have a M5R2 on the back of my 351w and I love it. Only negative I would say is it's a heavy S.O.B.(when installing by yourself) and the bell housing is part of the casting of the body. But it's worth the effort to me.

JedCrone May 20th, 2019 10:24 AM

Thanks foe the reply harrison28.

Did you convert from an auto to the M5R2 or from a manual? Since I have an auto, I'm trying to figure out what parts I would need to buy. This is my best guess so far:

From a doner: Transmission, clutch pedal, master and slave cylinders

New: flywheel, clutch, driveshaft

Does that sound right? Then I've read I would need to move the transmission support back and drill new holes and obviously cut a hole in the floor for a shifter. Did you do all the work yourself and is there any advice you have for me?

harrison28 May 20th, 2019 02:08 PM

My truck was an auto originally. I had another truck to take the brake/clutch pedal assembly, trans tunnel cover from. I replaced the master cylinder with a new unit. I did have to move the trans support forward a few inches, but there were holes there already so no drilling needed. I originally swapped steering columns also to get rid of the auto shifter and removed the gear dial out of the instrument cluster. Had to put the auto column back in due to the electric connection falling apart. Just removed the shift handle.

JedCrone May 20th, 2019 02:15 PM

What flywheel did you use? Did the bell housing bolt right up? And did you use the same starter?

Thanks for the help so far.

harrison28 May 20th, 2019 02:25 PM

I went from an E4OD to the M5R2, so I needed a different starter. The bendix on an automatic starter doesn't pull back far enough to miss the flywheel. It may be different going from a C4. The donor truck was mine to start with,....I ordered that flywheel and clutch kit probably 6 years ago when I was originally building that one up. I can't remember any of the details for it. But it had less then 100 miles of use on it.

JedCrone May 20th, 2019 02:32 PM

Cool. Well depending on time/money, I may do that swap. I really want to, but I would have a lot of questions and learning to do. My truck is my daily so if I can't find something to use for a while instead of that, I may go with something faster and easier like another c4 or a rebuild.

harrison28 May 20th, 2019 02:36 PM

I understand. It's hard to have the daily driver down for long. It may be quicker to get the C4 rebuilt. Plus having some sort of warranty will comfort the financial blow. Good luck.

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