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Trans differences

68 special

Well-known member
Joined
Jan 17, 2004
Messages
524
I did a search and couldn't find what I was looking for in any other posts, so here's the questions.

How do you tell the difference between a c4 and an fmx trans? The drive train in my car was swapped out years ago due to it originally having a 6 cyl. and changed over to a v8. With alot of searching I found out the rearend is a '67 with 3.00 gears and I thought the trans was a c4, but it has a 15 bolt pan. According to what I've found so far, the c4 has an 11 bolt pan and the the fmx has a 15 bolt pan. Are there other ways to tell the difference just by looking at it in the car? Could this also be the problem with my speedo not reading correctly? Wrong speedo gear? Is an fmx reliable or should I consider a c4?
I know this is alot of questions, so any help would be greatly appreciated.
Thanks Bret
 

nfrntau

Well-known member
Joined
Aug 15, 2004
Messages
1,020
Location
Rosharon, Texas
If your car is running I would suggest swinging by a trans shop and ask them. They look at them all the time and should be able to tell you with a quick look just what you have.
 
OP
OP
68 special

68 special

Well-known member
Joined
Jan 17, 2004
Messages
524
Thats a good idea, depending on the weather. It's supposed to to snow tonight and the next couple of days. If I can't drive it, I'll give them a call.
Thanks for input. Bret
 

Mosesatm

Well-known member
Joined
Jan 18, 2005
Messages
9,011
From the 2nd link it looks like C4 and C6 have aluminum cases and the FMX has a cast iron case.
 

PB GT/CS

Active member
Joined
Dec 22, 2005
Messages
32
Location
Kansas City, Mo
My understanding is the easiest way to tell the difference is the Bolt on Bell housing. If the bell housing can come off, it is a C4.

Brian
 
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