rockcrawler304

I know I shouldn't post this because it will probably jinx me but I just turned 121k on my stock clutch. Smarty Jr since 60k miles. I can easily slip it on SW1 in 5th and 6th and sometimes 4th if I hit it too hard.

tool

At 170,000 mine is still holding just fine. Lots of heavy towing.

I am wondering if my new vibration is a failing dmf though?

AH64ID

That's an impressive life!

rockcrawler304

I thought my 121k was pushing my luck and pretty impressive but WOW!!

AH64ID

There are just too many sudden failures of the DMF to not overlook. A lot depends on use as well, it seems if you can break 100K you can make 150K, but ???

My dad's truck will get some pretty severe service for about 5 weeks at the end of September thru October, a long ways from home and a long ways from pavement. That's the main reason it's being pulled out now, and not when it fails.

rockcrawler304

I also think it has to do with I ALWAYS push the clutch in when I shut it down. I think this takes some of the sudden jerk out of the flywheel. At least in my mind it does

AH64ID

My old man doesn't do that, but I attribute his longer than average clutch life to lots of long highway trips (mostly towing) and the fact that he drives like the old man he is. He rarely applies fuel prior to the clutch being fully engaged as well.

tool

There is no need to give your truck fuel when letting the clutch out on these trucks most situations. The torque of the Cummins will get you rolling even loaded if you are selecting the appropriate gear.

Because I am replacing my cracked transfer case I ordered a Southbend replacement and upgraded hydraulics yesterday. As well as a Smarty Junior.

I figure if I am into the driveline that far I may as well keep going and replace the clutch as well at a little over 170,000 miles.

I REALLY hope a failing DMF is the cause of my high RPM vibration.

tool

Well I am off to replace my stock clutch with a Southbend Con O FE It still hasn't slipped even with my Smarty Jr on SW3. But the vibration is getting worse. Hope that is the problem.

Wish me luck boys!

rockcrawler304

Good Luck!! Keep us posted

rockcrawler304

Update on mine...
135,000 and just put in a SB G56 OK-HD and love it. Mine would slip with the Smarty Jr on SW2 in 4th to 6th real easy but still manageable with a soft foot. I "Thought" my throwout bearing was going bad so I just did the clutch. Turns out the noise I was hearing is STILL there so it was not the throwout bearing But I know I was on borrowed time so glad I did it now.

tool

Well this is sure reviving an old thread. I don't know what made me think of it today but I just thought I should update.

I replaced my stock DMF and clutch setup 3 years ago at 170,000+ miles after my truck developed a vibration especially at higher rpm. It was a failed DMF, the clutch disc still had PLENTY of material left on it, I bet the clutch could have gone another 100K had the flywheel not failed. I replaced with the South Bend Con O Fe kit.

It's been fine although this setup has always engaged higher on the pedal than I'd like.

Truck has 230,000 miles or so on it now.

bradler

117k on the stock clutch. Getting worried the DMF is letting go. Almost replaced it this fall but can't afford the down time now so hopefully it doesn't chit the bed in a blizzard up north.

LOWTYD

Just turned 235,000 with the stock clutch. I’ve had the below mods since it had about 35 miles on it. I always run the programmer on towing mode. You can absolutely slip it if you mash it in a higher gear, say rolling along in 6th and mash it, it will slip once the boost builds. It would probably benefit from an upgraded clutch but it pulls our camper fine and give no issues.

SolarExpress

As stated earlier in this thread, my stock clutch went at 275k miles. I actually just lost the throw out beating. Replacement clutch was a Valeo. Those are junk apparently as it only lasted 80K miles and pilot bearing took out my input shaft in the process. Not happy. So new input shaft and new LUK clutch. This LUK engages at the bottom like the factory clutch and is immensely easier to push in than the Valeo. It's also copper embedded instead of asbestos. We'll see...