Engine/Transmission (1994 - 1998) limits of the stock input shaft (auto)

[Bandit1]

for power see sig, i want to add a set of 370's and a new turbo, only prob is i still have the stock input and output shafts (new ones werent available when i upgraded, only cryo'd) i dont tow much at all maybe 2 times a year and at the most is 8k, i dont race unless someone provokes me, i just like my daily driving to fly. are these upgrades going to kill the input shaft? or can i take it easy and get by for a little while before i upgrade to the billet input shaft. any info is appreciated. thanks

 

[HoleshotHolset]

IMHO: You'll be fine without the billet shafts... you don't race or tow heavy... and you're not going to be putting all that much power to the ground.



Matt

 

[Jim Fulmer]

Mine lasted to 690 HP then it sheared the teeth off the hub... ... . yours should be fine.



Jim

 

[Bandit1]

music to my ears, thanks guys for the reassureance. if any one else has some info please post.

 

[Lsfarm]

Input Shaft Roulette

Well, I thought I could get away with a stock input shaft untill it was 'convienent' to install a billet one. So I ordered the billet shaft and about three months later:... .....

I was driving to the airport, merging with freeway trafic. in OD locked about 55 mph or so, light throttle little or no boost. Ran over slight bump in freeway concrete. And...



Bing! I'm in neutral, for good. I coast to the side of the freeway, check everything out, I still have Park, so the output shaft is intact, but no forward or reverse. I'm done. A $200 tow [flatbed] later and I have to take two days off work. I now find it 'convienent' to install the billet input shaft.



History on the truck: It was my '01, I had only brake-torqued it for drag racing four times, at TIM four months earlier. Nothing since. The truck at that time had Edge drag comp, BD3's. DTT 89% Stock tires.



So I was driving it gentle-to-normal, not on the power, and the input shaft just decided to break. It broke clean, straight shear, not a twisted fracture. You can see the obvious crystal structure of the cast steel at the fracture point.



It boils down to this: it will live untill it decides it is ready to break, it is a casting, brittle like glass, not a forging.



You may get away with the power upgrades you mention, or you may have the shaft break before you get to install them, it is a gamble.



Greg L.