clutch slippage

There is some truth to this. We have performed this many times with success. Basically there is just impurities on all face surfaces that need to be burnt off. This is the same process as burnishing new brake shoes. Doing this now also puts a heat cycle through during the mating process and actually extends the life of the clutch. Think of it this way, if you don't burnt out the impurities now, they will get baked into the disks and flywheel over the course of time and cause shorten life span. I went to an Eaton driveline training course and we talked about this and said the same thing, and recommended a slip time of about 15-20 seconds. There really is nothing wrong with the clutch. Probably what happened is there was a greasy finger print or two that ended up on the surface of the flywheel or one of the discs. Clutches are a dirty and greasy job and no matter how the guys try to keep everything clean, these things happen. You should get good results!

 

I have put hundreds of clutches in either on purpose when they went bad, or during engine/transmission replacements and have never had a clutch slip after replacement. I have never heard of a breakin period either. The grease finger print thing should last as an excuse the first tie the clutch is disengaged. It still sounds like the pressure plate assembly issue.

 

You are right. Not every clutch install needs "break in". As a matter of fact, reread my post, I never said anything about "breaking in". Yes, a new clutch should work perfectly when new. Things don't go perfect every time. I am still looking for this secret land where everything is perfect every time! Some people live there apparently. Anyway, this is real world and sometimes not everything goes perfect, but there are little things you can do here and there. Sometimes clutches do slip, for whatever reason. It doesn't take long to try to burn it in to see if that corrects the slipping problem. Or, you can just spend another day down and $2000 bucks to replace a clutch that may get warranty denied because there is nothing wrong with it. Who pays for that?

 

NEVER EVER ALLOW A REMAN CLUTCH TO BE INSTALLED IN YOUR TRUCK. PURCHASE A BRAND NEW UNIT.
WHY? The rebuilder NEVER stands behind their JUNK product.
The shop doesn't warranty labor so you pay again!
This is the reason many shops sell JUNK REMAN CLUTCHES, for repeat business!
They know they have a high failure rate and clutch labor times is GOOD MONEY TO THEM!
Clutches always show any weakness in high gear.

 

I did not do a lot of clutches but have done enough to smell a rat on this, there is no way a ceramic clutch is made to slip. As long as the flywheel is resurfaced and the pieces are assembled properly, there is no slippage PERIOD.
A re-man clutch is just as good as new as long as it is from a decent supplier. I worked for a dealership so we always used a name brand clutch and I never found the price was different enough to use a cheaper alternative, jobber parts have there place, please tell us the name of the clutch and the repair facility so no one else gets caught.

 

Bender you got it half right. Install a new unit not a reman. Remans are more trouble than the savings are worth. Good advise.
I have been repairing trucks for almost 30 years & have never sold & installed a part with the mindset that if it fails I get to bill the customer again. I win! I don't know any shops who look for that. The work is hard enough to do once & nobody needs the practice.
When we install a part that fails if we cant get labor coverage we eat it.
Back to the original topic.
A few years ago we had some clutches that did slip initally but stopped within a short period. We never had to replace them. Perhaps the finish on the flywheel was too course & took some time wear in.

 

No ceramic clutch is designed to be seated by slipping it after installation.

As the clutch slips it pulls steel from the steel plates and deposits them on the ceramic pucks. This causes the ceramic material to lose it's coefficient of friction difference between the steel plates and the ceramic material. This causes the clutch to shorten it's life span in the truck.

With a 2050 torque rated clutch behind a 1650 torque engine something is seriously wrong with either the flywheel surface or the installation. A 2050 torque clutch from Spicer doesn't slip in a brand new truck when you buy one in a new Peterbilt, does it? And to think this would be behind an engine with 400 Lb-Ft of torque

 

I'm not saying that all shops follow this practice for their own gain, but I know some that do, and you should be aware that some independent shops setup targets such as the "clutch job" to spice up their revenue. It goes like this, and I am not lying.

Customer comes to shop with complaint of slipping clutch.
Manager writes it up for clutch adjustment.
Manager instructs mechanic to add free travel through internal adjustment and adjust clutch brake through linkage adjustment (yes backwards).
This insures the clutch won't work or feel right to the driver (high release point and possible slippage).
The manager then tells the driver to give it a try and he does but soon calls his boss and states the clutch is gone.
The drivers boss calls the shop and sets up clutch replacement and no one is the wiser to the scam.
Clutch is replaced with reman unit that got marked up by parts dept to the price of a new unit.
30% of these remans never haul a load without being replaced.
75% don't make it a year and after 90 days no warranty on labor and rebuilder won't warranty parts.
Customer pays again all parts and labor.