Clutch problem

[typ4]

Hello guys and gals,
Here is a problem I dont have much experience with.
Pre memorial weekend I installed new clutch and trans/ tcase. Less than 5000 miles ago.
Yesterday on the way back from a parts run on pretty flat ground engine revved as if clutch was slipping, went doen to fourth gear applied throttle, slipped again, so im freaking out, this is a new LUK, 100 K on last one, still gripping when the center grenaded.
So I get to shop, crawl all over to see if my welded bellhousing broke, loose bolts, bad slave . oil on clutch . All negetive.
So I push the fork/slave in to see if catching, seizing so on, nope all is good. TOB free on sleeve.
Check master free play, good. Nurse it home a couple hours later.
This morning tested it up a steep hill, full power no slipping, all good.
Any Ideas???? Slave catching, needs bled? I dunno.
Thanks in advance

 

[BrianX128]

Not the exact same, but my straight six with a m5od has a slow return on the clutch coming back up. It can make me slip in fourth gear. I had a giant master slave cylinder debacle with it and I know it's not 100% right but it will do it when cold or if it sits for a while between trips until I shift through all the gears a few times and it goes away. Not the same trans but you might be right with why cause I know that my issue. Yet if it's all warmed up and been shifted a bunch I can't get it to slip..

 

[Thewespaul]

Is this the truck with a bull moose ip? I don’t believe the luk clutches are rated for much more power than the stock 11”

 

[lotzagoodstuff]

How cold was it outside Russ? Just wondering if you're slave cylinder got hung up and didn't disengage your clutch completely. If you happened to have any moisture in your hydraulic system and it was cold, maybe it got hung up.

 

[typ4]

35 degrees.
My other luk held . And I make lots of torque.
I'm going to flush the fluid tomorrow. Slave is 8 yrs old.
And last week I had a 19 psi run and it didn't slip .
I'm sure it's in the hydraulics.

 

[jrad235]

I've only had that happen with the DMF, so yes probably hydraulics or something got onto your disc and then burnt off.

 

[Macrobb]

It's hydraulics. Those LuK clutches will hold quite a bit. No problem with my 250@the wheels... it locks right up for me.
I'd be thinking something is sticking - remember, the LuK clutch has a lot less force than other clutches I've seen, so just a bit of sticking force could make a difference here.

Also, I know for a fact that an 11" DMF will hold 250rwhp as well... cold. Get it hot, and it'll slip at a fraction of that. It's not the clutch disk that's slipping, though, just the "torque limiter" clutch in the flywheel.

 

[pelky350]

Sounds hydraulic related to me but since you just changed it I wonder if some sort of containment got onto the disk(thread lok, grease, oil or something?) if the slave is 9 years old it could be time, any moisture tends to go to the bottom most part, even just very little over the years will eventually take some effect. I think for about 100$ you can get a pre-bled master and slave cylinder with new line/fluid. I replaced them separate and bleeding the clutch was a pain to do but was doable eventually

 

[Double-S-Diesel]

had the same thing happen in my 96 about 10 yrs ago.
it was also in the cold.
dont know what the cause was, didnt change anything and it never did it again

 

[typ4]

Its been fine today and I towed a heavy load, trial by fire I know. There is nothing on the disc.
Anyway im going to make fittings to eliminate the plastic line and go to a stainless teflon brake line. And change out the slave. Turns out I have 4 new ones on the shelf.

I have never had trouble bleeding anythings so that part doesnt bother me.
If it does it again I will let all know.
Thanks for the ideas, like I said this is a new problem with no obvious cause for me.
And here I thought I knew it all!!!!!!!!!!!

NOT:)

 

[79jasper]

Just a fyi, you can buy AN fittings for these.

Sent from my SM-G892A using Tapatalk

 

[typ4]

Just a fyi, you can buy AN fittings for these.

Sent from my SM-G892A using Tapatalk

Where???? please.

 

[typ4]

Ahhh, just found them in Russell. I didnt know that. That will save some time. Thanks

 

[Macrobb]

Alright, share your part numbers! No hogging all the fun!

 

[lotzagoodstuff]

Ahhh, just found them in Russell. I didnt know that. That will save some time. Thanks

What’s the port size on the master and slave, and what size AN and/or hose do you want to get to?