Carnage, input shaft failure. 600 Cat w/18 speed.

[mwilson]

Wow, this is from a friends Peterbilt.



Looks like he will be in for some parts Monday...

Mike.

 

[Bill Stockard]

Wow, this is from a friends Peterbilt.



Looks like he will be in for some parts Monday...



View attachment 84954







Mike.

What caused that? Operator error?



Bill

 

[E7mack96]

was it a c16 cat? the one with the 2250 tq trans? I had one do that... operator error (one of my drivers) . . lol

 

[BIGNASTY]

:-laf:-laf
Tried to tell the people where I worked that JUST BECAUSE THEY HAVE A CLASS A DONT MAKE THEM A DRIVER!!!!!

Will never know but I was wondering if it was in the lower side when it EXPLODED?

Clutch looks kind of used up also maybe just the pic.

 

[BIGNASTY]

:-laf Can you imagine what that sounded like INSIDE THE CAB :-laf:-laf

 

[mwilson]

My friend owns this truck, his pride and joy. He is a very careful driver. Not to say he didn't mis-time a traffic light or bump a loading dock just wrong.



We were discussing this very thing last Monday at work, more of these input shaft failures are occuring. We THINK that with a good driver and better damping on the newer clutch discs that the old yardstick of change the input shaft after the discs have worn into the spines no longer holds true. We may begin to insist on an input shaft replacement as part of any clutch job with these higher power engines. We already mandate that the flywheels be turned as a part of any clutch replacement.



Will be talking to him this week and will find out what he thinks went wrong.



Mike.

 

[BIGNASTY]

My friend owns this truck, his pride and joy. He is a very careful driver. Not to say he didn't mis-time a traffic light or bump a loading dock just wrong.



We were discussing this very thing last Monday at work, more of these input shaft failures are occuring. We THINK that with a good driver and better damping on the newer clutch discs that the old yardstick of change the input shaft after the discs have worn into the spines no longer holds true. We may begin to insist on an input shaft replacement as part of any clutch job with these higher power engines. We already mandate that the flywheels be turned as a part of any clutch replacement.



Will be talking to him this week and will find out what he thinks went wrong.



Mike.

OH I was thinking that there was a driver for hire driving. The flywheel was ALWAYS a part of clutch replacement on our trucks at work. Is he into HEAVY LOADS as part of his job?

 

[HBarlow]

Mike,

What is the diameter of that input shaft? It looks surprisingly small in diameter to someone who has never seen one before or at least doesn't remember seeing one. I would have expected an input shaft with about a 2 1/2" or 2 3/4" diameter to handle the incredible torque those engines produce working against great traction and 80k to 110k lbs.

 

[mwilson]

Mike,



What is the diameter of that input shaft? It looks surprisingly small in diameter to someone who has never seen one before or at least doesn't remember seeing one. I would have expected an input shaft with about a 2 1/2" or 2 3/4" diameter to handle the incredible torque those engines produce working against great traction and 80k to 110k lbs.

2" which is the standard diameter. Pretty amazing when you figure some trucks are pushing 2200 ft. lbs. of torque.

Mike.

 

[NIsaacs]

Mike,



What is the diameter of that input shaft? It looks surprisingly small in diameter to someone who has never seen one before or at least doesn't remember seeing one. I would have expected an input shaft with about a 2 1/2" or 2 3/4" diameter to handle the incredible torque those engines produce working against great traction and 80k to 110k lbs.

It looks like a standard 2" 10 spline, the same size used in the old 220, you would think that they would get bigger. since the power has trippled.



Mike, without looking at everything, it's hard to say what broke first, the pressure plate or the input shaft. You would think that if the input shaft broke first that it would just stop going, that since the shaft is encased in the clutch disks how would it cause all that? I think that the pressure plate had a hernia in the release system and caused the input shaft to break. It will be interesting to see what the final story might be.



Nick

 

[mwilson]

A 2" input shaft launches these as well.

 

[GCroyle]

I don't have the numbers here at home and they might be at work, but a few years ago I spent a couple of days getting tutored on the classic Class 8 clutch systems. We're not supplying them anymore though. One thing that I do remember but the numbers aren't here right now, today's engines can exceed the torque capacity of a 2" 10T spined shaft and a bigger shaft was coming.

 

[NIsaacs]

Gary, do you have any stats on the big truck clutchs? I never liked the 15. 5" Spicer, they were failure prone. In my opinion, the 14" was way better. Again just my opinion, but I think the 15. 5" was a problem because the two disks and center plate were housed in the pressure plate and the 14", they were housed in the flywheel. The 14" just seemed to last longer and looked to be better built even tho they had less torque capacity.



Nick

 

[mwilson]

Gary, do you have any stats on the big truck clutchs? I never liked the 15. 5" Spicer, they were failure prone. In my opinion, the 14" was way better. Again just my opinion, but I think the 15. 5" was a problem because the two disks and center plate were housed in the pressure plate and the 14", they were housed in the flywheel. The 14" just seemed to last longer and looked to be better built even tho they had less torque capacity.



Nick

One thing that evolved over the years with the 15. 5" clutch is they have increased the size of the flywheel recess so that a bigger hub/spring pack can be used. If you look at the disc in the picture that is for a 10" recess. It is as least an 1850 ft. lb clutch unit.

In the 80's flywheels were 7", then were increased to 8. 5" in the early 90's and now 10". That makes a huge difference in the capacity of the clutch. And if a fleet or customer doesn't want or need a clutch that big the smaller clutches can still be used with the 10" recess flywheel.



Mike.

 

[GCroyle]

Nick,



Short answer no stats other than what is commonly published knowledge. We tried to make a go of these, but not everything pans out. But I did spend about 3 days at Illinois Auto Truck with a long time lets honestly call him Mr. Clutch Guy, he had a vast history and experience.



14 vs 15, was the 14 a survivor because it wasn't seeing to torque load thrown at the 15's? I don't have that answer.

 

[NIsaacs]

One thing that evolved over the years with the 15. 5" clutch is they have increased the size of the flywheel recess so that a bigger hub/spring pack can be used.



Mike.

Back in my day, they were all solid hub, no springs



Nick

 

[GCroyle]

Mike,



Interpreting the carnage is always interesting and I don't have experience on these, but looks like th input shaft is broken just about between the two discs. History of truck is always helpful, but if the driver dotted his I's and crossed his T's what does the condition of the input shaft right at the pilot bearing tell us and the condition of the pilot itself? Next, the disc splines. Straight and sharp as broached? Or washed out and real sloppy on a new shaft? Hub slop. Does the hub move up and down, L to R etc more than normal? Reading the damper, splines and pilot tell a lot about how well aligned the whole system was as it racked up the miles. Any chance to dial indicate the housing bore and face from the crank?



Hopefully this ain't much more than an ugly that some cash money and TLC can fix.

 

[mwilson]

One thing that evolved over the years with the 15. 5" clutch is they have increased the size of the flywheel recess so that a bigger hub/spring pack can be used. If you look at the disc in the picture that is for a 10" recess. It is as least an 1850 ft. lb clutch unit.

In the 80's flywheels were 7", then were increased to 8. 5" in the early 90's and now 10". That makes a huge difference in the capacity of the clutch. And if a fleet or customer doesn't want or need a clutch that big the smaller clutches can still be used with the 10" recess flywheel.



Mike.

Use this link,

http://www.roadranger.com/rr/ProductsServices/ProductsbyCategory/Clutches/index.htm



once the page opens it will look like this... .

Choose clutch selector (fourth choice down from the top right) and a two page pdf will load. Go to the second page and there are all of the clutches with torque ratings, etc.....



Mike.

 

[rbattelle]

It looks to me like there was no damage to the transmission housing. Is that correct?

-Ryan

 

[S.Morris]

Did his foot slip off the clutch in a higher gear? Lifting a load should have dropped a driveshaft or broke an axle or sheared a through shaft.



Every clutch job in our shop got cross shafts,cross shaft bushings, fork, clutch arm (if aluminum) pilot brg, release brg, input shaft (most of the time) , clutch , fllywheel turned, and rear main seal. Cutting any of these corners would guarantee that the NEW (no remans) would not last as long as the first new clutch did.



In several hundereds of trannies and clutch jobs completed, I have seen a lot of carnage but never a input shaft as pictured. (Seen lots of twisted gears on eighteen speed back section countershafts)I have been out of it since 98 though.



Brings back memories... ... . not all of them good. LOL