ID C-4 trans Walt Dupont

Walt Dupont--Me.

Walt Dupont--Me.

Well-known member
I've been a flathead nut for 60 years but thought I'd better ask this question on the later barn. I have a vintage front engine flathead dragster. We run 1/8 track up here in Me. I'm tired of breaking std trans. I just picked up C-4 with the adapter to the flathead. I don't know much about C-4 trans so this is my first question, It does not have a tag bolted to the first and reverse servo cover. So how can I tell if it's (C-4 Dual Range Automatic) or a (C-4 Dual Semi Automatic?) I've been looking through old Motors Auto Repair Manual and come up with this question first. Thanks for any help. Walt
 
Walt
I know they have different splines and there are a pan fill and a case fill.
I have a case fill on my 8ba and it goes good I hold it in and manually shift it.
The Flat O Matic has a very small toque convertor.
I think that would be the weak point.
 
George/Maine said:
Walt
I know they have different splines and there are a pan fill and a case fill.
I have a case fill on my 8ba and it goes good I hold it in and manually shift it.
The Flat O Matic has a very small toque convertor.
I think that would be the weak point.
Click to expand...

Hi George. I'm going to get a 2500 high stall speed convertor and a shift kit and a manual shifter as soon as I can figure out what trans I have. I may get a trans lock out but there expensive. Walt
 
I have a TCI 450900 Saturday night Speical That I didn,t use.
Its for a pan fill 26 Spline 11 7/8 bolt pattern 1.375 crank pilot.
never used still in box 2,000 stall.
This would be used with the Speedway kit 8BA engine only ,large bellhousing 164 teeth.
I think the pan fill are harder to find.
 
I just went out in the shop and check the dip stick oil filler tube. The tube goes into the front of the trans about an inch above the pan. Does that tell what the trans is? a Dual Range or a Dual Semi? Walt
 
Walt Dupont--Me. said:
So how can I tell if it's (C-4 Dual Range Automatic) or a (C-4 Dual Semi Automatic?)
Click to expand...

Walt Probably the easiest way would be to drop the pan and look at the valve body. Get the part numbers off of the valve body to detirmine what year it is.

The early Valve body (Dual Range or "Green Dot") are not worth to use as a performance trans due to the shift pattern. Also it has a small 24/24 spline input shaft.

Ford changed the VB in '67 to the P-R-N-D-2-1 pattern. It has a 9 bolt pattern and can fit the '64-'69 C-4 case.

In '70 Ford changed the case and the VB to a 8 bolt pattern. The '70 had a one year only 26/26 input shaft. The '71 up C-4 is the best to use for performance applications. It has the larger 24/26 input shaft among other things. It was made in either case fill or pan fill. The case fill is physically smaller in size to fit in cars. The pan fill was used mainly in trucks.

The C-5 is basically a C-4 with a lockup converter for economy.

I hope this helps some… :eek::eek:
 
Last edited:
Y-Blockhead said:
Walt Probably the easiest way would be to drop the pan and look at the valve body. Get the part numbers off of the valve body to detirmine what year it is.

The early Valve body (Dual Range or "Green Dot") are not worth to use as a performance trans due to the shift pattern.

In
Click to expand...

Thanks Y-Blockhead. Walt
 
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