Modded Mustang Forums banner

Broke the factory input shaft

1 reading
9.3K views 20 replies 15 participants last post by  07 Boss  
#1 ·
Hey all, I busted the factory input shaft and figured Id share the struggle im having in the repair.

1. A little research informs me that the stock 10 spline shaft is crap.
2. Ordered a 26 spline shaft for it (439 bucks Canadian)
3. Have to get a new clutch disc now (JUST installed a Centreforce DFX)
4. NOBODY in Canada has JUST the disc (6-8 weeks away)
5. Centreforce guys help me track down an Offroad place in Michegan that can get me one in a week...
6. Probably need a new input bearing as well as the various seals etc.
7. Pay a shop to put it in.

Point is ill be into this stockish transmission for almost 1600 bucks. Compare that cost to a built TR3650 and its not even worth repairing the broken input on the stock gear box. Perhaps this is a problem unique to Canada where performance parts can be difficult to find, but im sure Im not the only Canadian stang banger! Anybody else break an input shaft?:facepalm:
 
#3 ·
The tr6060 setup would have cost me around 4500. And it doesn't use a hydraulic clutch. Correct?
 
#4 ·
I broke 6 input shafts before Ford would no longer warranty them. I replaced 1 on my dime and when that one broke I ordered a 26 spline from American Powertrain. I never installed it and just bought a 4R70W built by FB Performance. Slicks + launching off the rev limiter + 10 psi from Kenne Bell 2.6 = broken ****.

If you are breaking input shafts you are going to end up breaking the rear differential. I went through 2 stock differentials and an Eaton Tru-Trac before swapping 9" with Detroit Locker.
 
#7 ·
#8 ·
Magnum XL is also high on my list after I'm supercharged. That, the Mcleod RXT (would have gone RST but after reading all the trouble people like Dimora had with it might as well spend the extra bucks and do it 'right' the first time) along with a Truetrac and I shouldn't have to worry about my drivetrain for a long, long time.
 
#9 ·
I have the Promotion Built 3650 in my car.. and the Mcleod RST twin.. trutrac Eaton
I didn't break my input shaft but it was extremely twisted and about to break

my drag racing days are over now but the drive train is still fine.. over 200 passes on the above setup at or near 550/610 hp/tq
 
#10 ·
This is why I always suggest to people to build from the ground up. Though I have an automatic, the input shaft is one of the weak links in my drivetrain. So before installing my blower, I installed a Level 10 tranny (rated to 800 hp) so that I wouldn't have these kinds of failures.
 
#11 ·
I'm building top down, LOL. I am hoping my current setup kills my tranny so I can justify a T56. :)
 
#18 ·
Lol
 
#19 ·
And also goes to show that the best laid plans can go awry when driving racecar. Yeah it sucks. As well as you plan, stuff breaks and you have to expect it to happen. I stick by my words though, proper build planning will help prevent, not eliminate, these things. Wonder how far I would have made it on the stock tranny? My mistake here was thinking I didn't need a billet piece and the cryo hardened piece was going to be good enough.

Goes to show there is nothing wrong with overbuilding. My shaft was supposed to handle 800 and I am well below 600. This time there will be a greater safety margin built in.