Differences

Yes the C5 is an excellent base though depending on what valvebody you might want to upgrade to a C4 valvebody. Heres some text i did a while ago on the differences


C4 vs C5 Differences


I was lucky enough today to score a c5 trans out of an F100.I have pulled it down to do a real comparison of the improvements + differences.
It even has a 'H' servo,the first i have ever seen.
The way to pick a c5 from the outside is
Deep pan(2.5"deep)
Fine thread on fr band adjuster
Large cooler fittings(1/4" thread)
E2 casting code
Starting at the back ,the #9 thrust washer has the normal 2 locate tangs but also has 2 cutouts to line up with an additional lube hole discussed in the c4 build post.The hole is drilled through the case to meet up withthe cooler return passage.The hole is 9/64".
The cooler return passage is also drilled to 13/64" which is larger than a c4(5/32"
The rear roller clutch spring retainer has the wafer springs clipped to it instead of being loose like a c4.
The front pump has no checkball in the stator support cooler passage and this passage is drilled to 1/4".A c4 has the passage at 3/16" and a ball fitted.
The ball can be removed on c4's to improve the oil flow in the cooler circuit.
Now moving inside, the sun gear where it fits into the front + rear planetaries has lube holes drilled to get the oil from the output shaft lube circuit to the gearsets.The C5 has 4 holes each end @.094" .The c4 only has 3 holes each end @ .040".
The forward hub has 5 clutches.It has a different bevel plate in the bottom of the clutchpack Which is .310"overall with a .110" step.
The c4 bevel plate is .265" with a .125"step.
The hi/rev clutch drum has 4 clutches @.078",All steels @.090" with a dished cushion plate on top.
Both the fwd + hi/rev clutches have a thin .140" pressure plates.
The hi/rev drum has the circlip grooved machined higher also as has been mentioned before that the c5 drum has the capacity for more clutches.
The top edge of the groove is down 1.020" where a c4 is down 1.082".
This trans is a case fill type and the input shaft has a recess about half way along it and it seems to be hardened.
I hope this info is useful as there has been a lot of discussion on the differences .These mods could be done to a c4 to improve the oiling to c5 specs.