Grit Dog

Truck in sig. Got about 70k trouble free miles on the ofe clutch and sb hydraulics. Truck is 90% DD, 10% camper and smaller trailers.
Truck started shifting hard. Like wouldn't shift into R 1 or 2 at a stop and had to match rpms to up or down shift. Thought it was bad hyd. No leaks. Adjusted pedal up and it was better but the clutch engages really slowly over the whole pedal travel.
Also can slip the clutch under load in higher gears now. 90 hp tune. Just hauled the big truck camper hundreds of miles and up mtn passes under load with no issues.
Slipping tells me the clutch is smoked but doesn't seem plausible as it slips pretty easy and 2 days ago I could floor it in 6th with a 2 ton camper in the bed with no problems.
Bad pilot bearing possible? No weird noises and clutch fork is real tight, no play at all when I removed the slave cyl.
Sheared some springs? Have had the exh brake for over a year now and use it.
Seems like hyd may be slowly going down again after adjusting the pedal up quite a bit. But that only explains the hard shifting not the slipping.
Any suggestions would be great before tearing it apart or just throwng new hydraulics on it.
Thanks.

HMX-1

Does it shift hard when the engine is off?

If not, then I'd start looking at the clutch.




-Kris

Grit Dog

Nope. Shifts fine with engine off.
Hard to believe the clutch went from hero to zero in one drive to the store.
The slave cyl does extend on its own when removed and takes some pressure to retract the Rod by hand then it pops back out.
Maybe it's putting enough pressure on the fork to slip under high load?

seafish

NOT necessarily the clutch, but rather the DMF (dual mass flywheel) that Dodge installed as part of the oem system to reduce the NVH (noise, vibration, harshness) that Cummins induces in the driveline. THE DMF are notorious for failing. All that being said, still means a clutch job while you are in there.

StealthDiesel

Grit Dog states in his 1st post that he has about 70k miles on a Southbend OFE clutch and Southbend hydraulics.

It does sound like the clutch has several issues.. Sounds like you have to pull it and check it out...

seafish

Ooops...my bad, no DMF.

Grit Dog

That's correct.
However when I removed the slave cylinder, the piston extends on it's own and requires some decent pressure to retract by hand. Not sure if that's normal or it could be leaking internally causing some residual pressure that could be causing the slipping as stated below.
In my experience when a clutch starts slipping it behaves the same except under load of course.
In this case it went from holding full boost uphill loads one day to not going into gear and completely different feel in the pedal and slipping while empty if I get into it in the higher gears.
It does not make sense to me that the clutch is bad. No oil leaks at the rear main to foul the clutch. Mostly used as my wife's daily driver with occasional light towing or truck camper. And like I said, fine one day hauling a 4500lb truck camper through the mountains and literally the next day this began happening on a drive to town empty.
If I had all my tools here in AK I could pull the trans pretty easily but I don't so would prefer to exhaust all options before getting into it. To top it off, the movers are packing us up in less than 2 weeks to move back to WA and any parts would take a week or so to ship here, like a new clutch haha.

I read while searching that some of the southbend clutches don't like the reverse torque of exhaust brake use. I've had an e brake on it for over a year now with a couple thousand miles loaded with the camper. Maybe that trashed the clutch??

Grit Dog

Ok to follow up, just talked to Southbend and they said that the clutch fork should have free play front to back and mine doesn't. It is tight.
Said that mo than likely means the throw out bearing is trashed and hanging up the clutch fork causing the symptoms described.

HMX-1

Good for you, at least it's not a whole new clutch!

Grit Dog

Yes hopefully that is the case. Couldn't find any help to pull the trans so it's going into the shop next week.......

Grit Dog

Well I was wrong. Clutch is/was smoked. And almost wore out.
Guess I, Imean my wife can kill a SB OFE in 70k miles driving the kids to soccer practice!
First shop wanted $2200 just to RnR the trans, plus any addl labor!! No thanks. Another week later got it into a good shop that isn't a ripofff.
SOuthbend was great to work with. Gave me a break on a new clutch and upgraded to a ceramic single disc.
Just waitin for the parts to all make it to AK.
Thx for the help.

rockcrawler304

I guess bad news and good news.

Does the wife ride the clutch a lot???

Grit Dog

I dunno?? Maybe?
Actually she babies it around most of the time, low rpm shifts, no downshifting when coming to a stop. Suffice it to say I USE the clutch a lot more when I'm driving and I definitely get on the skinny pedal harder.

Well it's all fixed now. Won't be able to drive it for a couple weeks yet until I return to AK and pick it up.
Between the great service from Southbend and a good honest shop, I got by for the about the cost of just a new SB single disk kit and didn't have to get my hands dirty!

Fisherguy

What clutch did you put in exactly, what model?
How do you like it, grabby at all?
I have a single disk OFE, been great.

Grit Dog

Just drove the truck for the first time today.
It feels pretty much like the OFE. It's grabby but not too bad although it's not bedded in yet and I haven't gotten on it good. Won't until it's got some miles on it.
I don't know what model it is. It's not one of their advertised clutches. I have to ask SB the details but he said he built a full ceramic finger style clutch. At the time I didn't ask too many questions. Said he'd build me a clutch that I couldn't wear out since I didn't get the best mileage out of the OFE! Works for me!
It rattles like he!! In neutral with the clutch engaged so I know it's not a diaphragm style. Oh well, the truck wasnt quiet to start with anyway.