Its not good when you break your (input) shaft...

M

moparman13045

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May 4, 2010
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Well on the freeway the other night, a buddy of mine had my truck heard a loud bang, rpms hit redline, then it was like i was in neutral coasting. Here are some pics of the outcome, 05 dodge ats transmission, suncoast billet input shaft. Truck dynos at 527hp at wheels 1105 ft lbs. I think I may have got somewhat lucky, the break looks clean, no pieces to be found anywhere, and none look to be missing out of the broken halves. Piece that is in converter still is stuck though, so might have messed up something in converter, but what are you gonna do.

Here are some carnage pics hoping pump is ok...

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If anybody has a stock good working order tranny I can buy just to put in the truck until I get this one fixed let me know!
 
Sorry to hear it's a suntoast! Don't even bother to try and get warranty they will laugh at you!
Call Dave at goerend and have a new billet shaft and TQ sent out asap! Slap it together and your done!
 
dangerous06 said:
Sorry to hear it's a suntoast! Don't even bother to try and get warranty they will laugh at you!
Call Dave at goerend and have a new billet shaft and TQ sent out asap! Slap it together and your done!
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Well there's your problem right there! SC parts HATE being stuffed inside purple trannies... NO WONDER it broke ;)

LOL @ SunToast

Shaft's indeed don't carry warranties, although 550hp seems like a low HP number to be popping inputs... if it becomes a trend maybe a larger than stock billet input is up your alley
 
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my fully built ATS tranny broke three times in 30,000 miles and a year and a half at maybe 600hp but its a 4r100 ford tranny. took out the TC, input, planetary, and intermediate. then i tore it all down to find all the clutches and other parts were nearly shot.
 
Guys what is usually the cause of billet inputs breaking? I have dynoed my truck at 520 hp 1090 tq at the wheels its an 05 4X4 QCSB ats intake, exhaust manifold, aurora 3000 turbo, 90hp nozzles, 5" tb exhaust, smarty tnt, ats trans with suncoast billet shaft, no converter lockup switch or anything. I have launched at dragstrip at no more than 12psi in 4x4. Only a few runs down the strip, and about 2 truck pulls.
 
Were you with your friend when it broke?

He was just driving calmly on the highway when the shaft just suddenly snapped?

How many miles on the shaft? Are you sure it's a billet suncoast shaft? Where did you purchase it from?

I would start there first.....
 
I am not an expert on metals at all, so....

The breakage does not appear to be from fatigue. If the splines were not twisted, then I would also guess that it wasn't being over powered.

By what I can see in the pics (which is not that much), I would look at a side to side flexing of the shaft. What flex plate did you have? Were the bell housing alignment dowels in good shape and installed. The bell housing should not be aligned with the bolts, but with the dowels. Did the snout of the torque converter fit tight in the flex plate center hole? On our pickups the torque converter centers into the flex plate and not the crank. Was there any runout in the flex plate?

IMO all to often a broken shaft gets blamed on the shaft, when it is something else. Check everything carefully, or you maybe repeating the problem.

Hope this helps...
Paul
 
I once broke a billet input with 575rwhp. I drove the truck hard, constantly did wot lock-up shifts...the input broke and shock loaded the intermediate shaft, a week later the billet intermediate broke. The billet output shaft barely made it...it had a twist in the splined area.
 
LReiff said:
Some people put their own transmissions together. :doh:
Click to expand...

I understand that but but when I hear ATS trans I would tend to think it being built by ATS. Heck anyone can paint a tranny housing purple that dont make it an ATS unless he sent the input to them to be installed? Just wondering as it sounded odd.
 
my stock input lasted 300k plus, and 60k at 500 plus rwhp and 1200 plus fpt. but it was on a light 2wd reg cab short bed. i guess i just got lucky
 
My 95' Junker Drag Truck has a stock input shaft. I'm sure it will break eventually but so far it's holding up fine and 90% of the time it is abused with locked WOT shifts at the drag strip. It averages 525-550 HP down the track, but it is 2wd which seems to really help with shaft life.

When Phil Taylor built the converter, he added a tapped plug on the cover of the converter than can be removed when the input breaks so it can be tapped out with a long punch from the back side.
 
A yeah runninlean and LReiff, I didn't build my tranny, it was built by ATS. Here is the deal, It was an ATS trans came in the truck, it didnt have a billet input from them. A short time after I owned the truck, it began to take a minute to engage on a cold start into drive or reverse. I took it to a guy about 30 mins from me who works on race transmissions. He took it apart and found that the pump plugs as he described them to me were not holding pressure. He described them as a pressed in plug in a port or ports in the pump. He said that they were the culprit as they were allowing pressure to bleed off which ended up causing my forward clutches to start slipping. So, he drilled and tapped them, and screwed in plugs so that they would never do that again. He also put all new ATS clutches, steels, seals, etc in at the time (about a year ago). I decided to buy a billet suncoast shaft (ats charges alot for their shafts) from a diesel performance shop which I will not name at this time, and had him install it while he was in the transmission knowing that I would be putting in 90hp injectors and wanting to go to the dragstrip etc. I also had him put in a billet flexplate at the time (a BD). Yes I mixed and matched brands, but it shouldn't matter. So there you have it, the shaft twisted around the outside before the center of it snapped. It snapped clean, it did not shatter, there are absolutely zero fragments of metal anywhere to be found. Shaft, flexplate and transmission since refresh have about 8k miles on them. I haven't had a chance to check the flexplate runout, but the dowel pins look to be perfect and centered perfectly. The guy who installed it is very meticulous, but who knows, I was just wondering if there were any common scenarios for input shafts breaking.
 
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Really hard shifting is usually the biggest culprit of snapped shafts as far as I know. Not locked shifts, but how hard/quick the trans is setup to shift through the valvebody.
 
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