New clutch slipping while wheeling

Hey guys, I have a bit of an issue. In the beginning of the summer I put in my new motor and with my new motor i put in a new luk clutch. I did it all properly, resurfacing the flywheel, using all new parts including the throwout bearing and pressure plate, and assembled it properly, but whenever i take my truck out and attempt to climb even small rocks or hills with decent slopes my clutch slips, sometimes it'll just slip a bit but sometimes it'll slip really badly, i don't think I'm approaching the climbs wrong and the clutch is brand new, it shouldn't wear this quickly with so few miles on it right? any help? thanks

 

If it's a clutch issue seems you'd have slippage under any hard load condition, not just a climb.

Nothing like that on the street? Tried the traditional 4th gear load test? Low RPM, high throttle?

If you don't get it there, maybe it's not the clutch you're feeling?

 

v6, right?

 

its a 4 cylinder, 2.7, I've never heard of the 4th gear thing but i know its the clutch because i can smell it and sometimes a bit of smoke will come from it, i don't dump the clutch at all i let it out smooth and it will sometimes just not catch and start slipping, on the road i have no issues, just doing small climbs, even to get on top of small rocks.

 

2 things i can think of

1, the machine shop didn't properly resurface the flywheel. Its a 2 stage cutting process that need to be a certain distance apart to funtion as intended.

Or you didn't clean the flywheel after it was resurfaced, leaving possible residues from grinding compounds to antifreeze on the surface. Leaving it slightly slicker.

Then again, see if theres play in the clutch pedal when released. If not, there may be a slight amount of force pressing down on the clutch.

 

there is a bit of play in the pedal but i remember the hydraulic being a bit messed up when we were putting the clutch in, we just pumped it a couple times and eventually it fixed itself, i don't think that'd be the issue, i cleaned the flywheel pretty well when i got it back with break cleaner as well

The picture is how they cut it and before I cleaned it, not sure if it helps but ill post it anyway

 

Curious if you do in fact have to get these machined in a special way. I have also heard the luk clutches are garbage

 

Yes, maintaining a .5mm step is OEM spec. MarlinCrawler will grind custom step amounts (higher) for those needing extra clamping force from any given clutch.

OP, since it's seems to be intermittent, look at the hydraulics. Like a sticking slave cylinder. You mentioned "hydraulic being a bit messed up".

 

did you properly break in the new clutch? if not, you may have glazed it over and possibly ruined the new clutch.

 

Is the step everyone talks about the visible step that starts 1" from the edge of the flywheel? Lol i cant figure this out

 

Yes, if only the wide inner "friction surface" is ground or surfaced significantly, it results in less than the designed clamping pressure on the disk. The result can be the same as a worn out (thinner) disk.

 

So, you remove the pins and machine the outside surface to 0.5mm difference? That makes sense!

 

Yes, all there is to it.

 

lol i think ive been doing more like 1mm step height for customers

oh well, better performance?

 

I did not break it in, I wasn't aware of that to be honest, hopefully I didn't ruin it though, I drove it normally for a couple weeks before I hit some trails. I think I recall seeing the step you're talking about. I'll take a look at the hydraulics. someone said luk are oem for Toyota along with aisin of course, I asked about the clutch in another thread before I installed it and looked it up too, most said it was a decent clutch. Today when I started the truck I noticed that when I pushed the clutch in while in neutral the RPMs dropped slightly and when I let off they go back up, this only happened (I believe) while cold, could that mean the hydraulic is sticking like you said? The difference was about 100-150 rpm, it could be normal I just kinda noticed it now when I was looking closely at it

 

For what its worth, Luk is an OEM replacement clutch for BMW and VW/Audi. I can say they're solid for those applications.

 

I am just saying I have seen people take out a new Clutch in less then 1000 miles.

New Clutch and you did not replace the hydraulics to me that is a no brainer !!

Don`t forget the rubber hose as well.

I venture to say Hydraulic issues .

I have a Luk Clutch in my 2000 about 60,000 miles no problems.

 

Dumb question but are you trying all the climbs in 4low?

 

Interesting, im about to do my clutch today and ive researched more than a few clutch builds on here. I dont see people replacing "hydraulics" too often. Do you mean clutch master cylinder and piston?

 

Unless you have other issues going on, you shouldn't need to replace or rebuild any of your hydraulics. I would take a few minutes and bleed or even flush the system. No time like the present to make sure you have good fluids.

Now, after replacing the clutch you might notice there were other issues you didn't know about.