i broke the input shaft in my Hughes Performance trans. I repalced the input shaft & the seals on the shaft. when I put the trans back in the truck trans trys to go forward in all gears including N & P. reverse locks up like there are two gears engaged. im getting tired of pulling this thing in & out & apart. my question is, Has any one broke an input shaft & did something elese break at the same time that i should look at, or that could cause the input shaft to break?????

Any help would be nice......

 

Usually the input sprag takes a beating and grenades when an input shaft breaks. Did you disassemble the unit completely to determine if there were any other damaged components when you had it apart?

g

 

Got any pics? was it the shaft itsself? or the drum that it splines into.

If its trying to move forward in N and P maybe your forward cluthes are bound up. Did you make sure to check the forward/overrun/and 3-4 pack clearances?

Like Gilbert said^^ I have had a forward sprag break other parts in my 4l60e from slipping and catching sending shock throughout the trans. I like to install Sonnax 2-3 HD valve thats applies the extra clutches over the sprag adding support. With this valve you need to race in "3" not OD position or "D" i think is on the trucks

 

Gilbert - Ill have to check that when i take it back apart. No i didnt disassemble the trans completely. ive never taken a chevy trans appart, i figured the less that i mess with the better off i would be. i know the input shafts are a weak link and was hoping theats all it was going to be. guess not....

silverz28camaro - no i didnt check any of the clearances, i just transfered everything into the new drum the way i took it out. yeah, it was just the shaft. its a cryogenically frozen shaft & the drum has a steel sleve pressed onto it to try and prevent the shaft spinning in the drum.

thanks for your advice, ill have to check those items.

Do you know were i can find specs for the forward/overrun/and 3-4 pack clearances?

[ATTACH][/ATTACH]

 

.020 on the over run. .030-.050 on the forward. OEM on the 3-4 is .035-.070, but I think most people will try for .035 for a better 2-3 shift.

How much power are you running? and what stall size? Did it break on a hard 1-2 shift? It seems if you can set the 1-2 on the soft side these transmissions can last a good while...

Make sure the bushings are fresh that the inouyt shaft rides on, worn bushings can cause slight vibrations and extra stress on the shaft

 

thanks for the info, that a lot of help. im not sure what the power is at, i know about what it should do but i wont make any claims with out proof. its running a ported magna charger at 9lbs of boost, a hughes performance 2000 stall. i actually broke it in 3rd gear. i was full throttle, 9lbs of boost, around 80-85mph or so & around 4500-5000rps or so, than pop & bounced off the rev limiter. Oops!!! i was driving down the road so i wasnt looking at the cluster when it happened

 

Lingenfelter sells the billet input shaft that they claim is string as Hell.

But I think it depends on how much money you really want to put into this trans...with the power you are probably at and with the weight a billet input and output would be ideal with some frsh bushings in critical areas.

Or you got the 4l80e swap option.

 

Before you go into it again, be sure to take a look around for some build threads if you don't have an ATSG book that will walk you through the rotating assembly. There are some good threads here and over on LS1tech as well.

A cryo'd shaft is a good idea, but I would seriously consider a billet shaft for this application as the power to weight ratio is what is going to kill it again.

Good Luck with it! Holler at me if you need anything, don't hesitate to pick up the phone and call bud.

g

 

Damn 60's they sure dont like our big heavy trucks with boost. Glade to here you still have your truck Str8klownin. keep us posted on what you find out when you pull it down.

 

I know its been awhile but, truck is back on the road again. Thank you to those who helped me out with info & support, so i figured i would update this thread now that the truck has been back on the road reliably now. I ended up welding a set of gears together causing the trans blew up when it shifted as well as blowing up the rear axle. I ended up replacing the trans with another Hughes Performance 4l60E trans with bullet input shaft this time & had the torque converter rebuilt with a 2800 stall. Great combination, Drives awesome. Had a custom rear axle built as well. Its a chevy 14 bolt center section with 10 bolt ends to retain my Baer big brakes. It shortened 1/2in and now has Auburn High Performance Series Differential & Moser 33 spline axles. With any luck the power train/drive train will be reliable for awhile. I would also like to thank Dave & Henery at Arizona Differential Specialists for the great job on the custom rear axle...