Section 4 of the Monster thread. '69 and earliers have the 24 while the '70 and later have the 26. To wit...
4 - Input shafts
Early transmissions used a 24-spline input shaft that is smaller and weaker than the 26. The early 24 spline input shafts have a diameter of .788" and the 26 spline shafts are .839". The 24 spline shaft trannies can be upgraded to a 26 by swapping the stator support and the hi/reverse and the forward drum. There's a how to at http://www.mustangcentral.net/tech/c4conversion.html GA - It is said that the factory 26 spline input shaft will take up to 600 hp. TR - Use of an after market hardened input shaft is only needed for the very high powered cars and heavy trucks. Up to 450 HP is fine for the stock one, above that it would be good insurance. 89C - Very few factory C-4 input shafts are hardened and seems that only the original C-4s that had the "R" servos had them (all mine came from trucks with yoke that bolts on tail shaft and 4WD C-4s with transfer cases bolted on where tail shaft goes.) If you can scratch the input shaft, then it isn't hardened. I have tweaked the splines and shafts of the non hardend inputs but not the hardened ones. (Once I found out they do exist from the factory.)
There are 3 input shafts/
Early up to 69 were .788" diameter and 24/24
70 only .839" and 26/26.This is a unique forward drum to suit this input shaft.
All after 70 were .839" and 26 at converter and 24 in forward drum..All aftermarket input shafts are based on this one.
C5 are the same though the c5 ones i've got have a bit of a recess along the shaft length
I just found this thread! it has a wealth of information in it! even more than I have in my personal archives.
I do wish the information about aditional clutches was a bit more detailed and maybe listed numbers... its ok as it is but all jumbled.
We should probably add some information about governor modifications and modulators and pins. It might be good to mention that before 1967 the pumps had O-rings and gaskets. The one big item that I couldn't find as I looked through it all, and I might have missed it, was standard adjustments. You know; WOT, Kickdown, Shift linkage and bands. Also installation tips like lubing convertor seals to prevent them from burning up before they get oil and putting oil in the tranny and converter before start-up.
All said and done it is a great source of info - Gregaust, why didn't you tell me that this was here?
<font size=-1>[ This Message was edited by: PaulS1950 on 9/28/06 5:03pm ]</font>
Thanks for your feedback. You are right on every count. That additional information is needed and would be a great addition. The clutch section is jumbled and does need part numbers and some more specifics.
Feel free to email me with your written and rewritten passages and I will gladly insert them.
Paul (R Code)
Here are some pictures i took of our C4 that twisted the input shaft and cracked open the forward drum , then strippe dout the inside splines. This is the second time this happened this year. We are running a fox body Mustang with 100 shot nitrous 302, 300 stall with trans lock running 7.50's and 1.60 60 foot. I learned alot from this forum about hardened shafts and weilded up forward drums so I purchased them and included them with the old parts in these pictures.
Here is a closeup of the cracked drum and the new welded drum. They weld up the peanut shape holes to streathen the drum hub.
Hey, I copied this and saved it on my laptop. I'm out of town on business for a few months, and internet time here is very limited (only 15 minutes a day). I read the main article in entirety, but ,forgive me if this has already been asked/answered. I am totally ignorant on transmissions, and hope to rectify this situation. I just bought a "built" C5 from a friend (who claims it is good up to 500 HP-I plan on going up to 550 HP with a 347, in a 67 Mustang Coupe, mainly for drag racing), and plan on making it better.
First off, What is an R and H servo? Also, I see Trans Brake Valve bodies, and Reverse Manual Valve Bodies. Most of the orignal writers of the main article say they prefer Manual Vlave Bodies. What is the difference between a Reverse Manual, and a Manual Valve Body? Well, that is it for now, I'll be sure to write down my questions tonight for better reference. Thanks in advance. JL
Great information R code, tons of stuff i know nothing about!
I do have a nasty flare up on my ,well, 2nd over to 3rd shift(70 C-4 with a Gear vendor over/under drive attached)
If you know the GV units basicaly they split each gear for 6 forward speeds,
the neat thing is you only loose maybe 100-160rpm between gear changes so the engine is always in its sweet rpm spot.
but, as i said, on the 2nd hi if you know what i mean, to 3rd i get a nasty flare up. I;m running a Sonax billet servo,
Do you think the Sonax is not releasing quick enough? should i maybe try an R servo?
Thanks for any help, should mention, it doesn;t always happen, which is kinda scary too!
My car a 69 Mustang 302 has a hotter cam. The shift point is original from 2-3 about at 4000 rpm. The Engine has potentzial for moore power. How can I change the shift points for higher rpm`s shift points ?
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