Bent input shaft on transmission
 

Guys, just wanted to know what could cause a "bent input shaft" on my transmission. Anyways, it looks like I'll be getting a new tranny now! :( (looks like the money pit continues to grow)

That's a new one on me. All the years of driving and hammering on manual trannys, breaking teeth on gears, I've never heard of such. Who told u ur's was bent?

I saw the trany, believe me, its bent! The car started sounding like a helicopter when pressing the clutch in and driving.

Was it in the car when it bent? I would not automatically make that assumption that is was. Was there a pilot bearing? How much side play on the rear main would be a question as well as the balance of the rotating assembly.

Scalliwag, It happened after I made a run and didn't think that I launched it that hard. I'm only running Yokohama AVS's on the rear. Anyways, after the run, the car started to make a terrible noise(clanking) from the bell housing and I could feel it in the clutch pedal.

I know before Ken Scheepers started balancing the rotating assemblies on his motors that he would only get about 4 or 5 passes on the rear main.
He lauches at 11k and has a spooled rearend with slicks so he hooks up real good.
The way the rear main would look made it very obvious that the motor torqued horribly against the side.
Since Ken has started balancing he now longer has that problem.
Something had to torque the shaft to the side real hard and/or the pilot bearing had to be either missing or really messed up.

Yeah, if you don't have a pilot bearing in there or all the rollers have fallen out the transmission is going to let you know about it.

Thanks fellas, that helps me out!

My 4 speed ribcase tranny has a bent shaft. :)

i twisted every shaft in the tranny..........yeah i know i'm special ;)

Guys, Does this mean I'm putting some good power through the driveline?

or you have a broken input shaft bearing ;)

Vosko, the bearing checked out GOOD, but will be replaced anyways.

Just to make sure everyone is on the right page here; There are two bearings to be concerned with, the pilot bearing (in the eshaft) and the input shaft bearing (in the tranny)

So, how could the shaft warp if the through-out and pilot bearings checked out ok?

when my tranny broke and twisted everything. i broke the input shaft bearing and lost 1st/5th gears. yeah it was cool :)

Vosko, you must have launched HARD! :)

We are not talking about the throwout bearing. That only works in engaging and disengaging the clutch and has nothing to do with the actual aligment and support of the input shaft.
The bearing on the transmission (internal) I would wonder about. But a bent shaft with no twist and a good pilot bearing bewilders the hell out of me and this is going to be something I have not seen.
I am trying to figure what could bend that shaft on a semi-hard launch. Just a bent shaft running in a pilot bearing should tear it up quick even if it was not the cause.

launching at 8500rpm on M&H's will do that apparently............. i had two trannies broken like that ! :)

Scalliwag, you're right! I just found out that the pilot bearing was thrashed! I was miss informed and had to find out for myself, anyhow, thanks for all the input fellas. These forums are sure helpfull!

Are you sure the shaft is actually bent? The pilot bearing would not cause that. It would be a result of the bent shaft. You need to wiggle the shaft and see if it has a lot of side play and/or makes a lot of racket like something is not right.
I would bet the only thing wrong is your pilot bearing went out and the shaft is still good.

Trust me, I saw the shaft. It rotates like its drunk!

looks like I have more worries now, it turns out that I might have a broken stationary gear on the rear rotor. The money pit is HUNGRY again!:(

Thread resurrection! (just over 10 years lol)

Speaking of bent input shafts...I may have one, but done in another way. Bear with me for the longish post.

I have some clutch chatter on a fairly brand new clutch (replaced a few years ago, but don't drive much) and think I rested the tranny on the input shaft too much when reinstalling the tranny after a clutch change. I'm getting quite a bit of vibration and clutch chatter especially in stop and go traffic.

I have a spare flywheel already machined and a brand new clutch kit (to make sure the disk is straight), pilot bearing and seal ready to fix the issue...but should I have the input shaft and input shaft bearing checked by a transmission shop, just to be safe? I wanna do this right.

edit/coles notes: if I did rest too much weight on the input shaft/pilot bearing/input shaft bearing/clutch disk during a clutch change, which would tend to mess up?

Test your trans mount(s). The rubber may be on its way out. Your're an FC owner so check your motor mounts too. One always breaks.