Slipped Clutch

[W_A_Watson_II]

OK, a question for those of you who are experts (or at least highly experienced) in clutches.

Back in the fall while playing with my M37 on some tailing dunes at the Bad Lands Off-Road Park in Attica Indiana I did a 2WD hill climb with tires aired down. Noticed the engine moving faster than the truck should have been and no huge rooster tails of rebels. Then a whiff of clutch, so out of the throttle I came.

Now after than I didn't notice any real change in how the truck hooked up or any additional slippage, just a little lingering smell.

So before I pull the transmission and the clutch to inspect it I dropped the inspection cover, and held the clutch pedal down to see what I can see. The flywheel and pressure plates both had a highly smooth and reflective surface to them and the pads looked close to original thickness.

I did notice a little surface texture on the pad that mates with the pressure plate.

So thoughts? Did I likely do any real damage? Do I go through the work and pull the transmission out to get the clutch out?


Here is what the clutch looked like new:

[W_A_Watson_II]

Here you can see the reflection of a rivet in the flywheel:

[Tom Petroff]

Tough call.
But if it's slipping under load you know it's not going to get better.
If you done anything to it you more than likely weakened the pressure plate springs from heat and it's loosing it's clamping ability.
Or possibly Glazed the disk.

It don't take much either.
Tom

[gyman98]

Well like Tom says you know it's not going to get better. A good way to field test a clutch is early shift into high gear while climbing a steep hill and mash the throttle, if it slips when the engine is in the power band then you know.

It's really all with what you can tolerate at this point, my 67 power wagon has had a slipping clutch for years but for its purpose it still works for what I need

[DrPepper]

Tom has a good point...

a clutch needs to be "broken in" and some are better than others about break in.
Two things come to mind....
1. Was the PP ever set properly by the manufacturer? I bought one from a local rebuilder that was supposed to be great quality. after considerable work I clamped it down and did a check of the settings and they were not even close.
2. A glazed disk and PP can be sanded down to renew the surface and sometimes "broken in again. Been there ... done that , and it worked.
3. I was told to put it up to a stout wall and it you let the clutch out in 1st and it stalls the engine it's OK. If it keep runnin'...replace it.

Best of luck on the outcome.
DrP

[Clint Dixon]

....I was told to put it up to a stout wall and it you let the clutch out in 1st and it stalls the engine it's OK. If it keep runnin'...replace it....

It had better be a really really stout wall. We're talking Dodge here.....;^)

Junior

[W_A_Watson_II]

But if it's slipping under load you know it's not going to get better.

True, once they start they seem to continue.

A good way to field test a clutch is early shift into high gear while climbing a steep hill and mash the throttle, if it slips when the engine is in the power band then you know.

If there was only a hear to be found in the flat lands of central IL.

a clutch needs to be "broken in" and some are better than others about break in.

The clutch has been in since 2009 and has less than 3K miles on it. Granted I'm not kind to the use.

It had better be a really really stout wall. We're talking Dodge here.....;^)

Oh so True! I was surprised I didn't brake an axle rather than slipping the clutch.

[W_A_Watson_II]

Nice weather today so I took it for a round the block test. In 1st idling I can press the brake and kill the truck, and in 3rd gear I can hold the brake and kill the motor, even giving it some throttle. But in 1st if I stand on the brake I believe I can get it to slip and overrun the brakes as well.

[712edf]

I guess it boils down to how much & for what do you intend to use it. Yes you will eventually have to correct this situation, but how much more damage will occur if you continue to drive it like it is, knowing & accounting (babying) for it.

Its a fix now or fix later issue. And I have taken the fix later route several times w/o any catastrophic results.

Bucky

[W_A_Watson_II]

Well, I decided I just had to find out and fix it, so:

It only took a couple of hours but I pulled the seats, floor, transmission, clutch and flywheel out. And as you guessed it's was toasted. Mostly near the center of the clutch. So I'll be headed off to the Clutch shop and get a new clutch and through out bearing and have the pressure plate and flywheel reconditioned. I also pulled the shiftier out to check it as I was having issues with how for I had to throw the shiftier to hit 3rd. It looked good, and I had another shift tower that shifted good so I'll swap it in as it will also give me a reve4rse light switch I didn't have.

[W_A_Watson_II]

[W_A_Watson_II]

[W_A_Watson_II]

[Cheyenne Dave]

Wow, your friction plate sure looks a lot different that any I have seen. I've not had an M-37 clutch out before. Any other friction plate I've seen had 100% coverage of clutch material, not pads like yours. Is this the way all M-37 friction plates are?

cd

[W_A_Watson_II]

This clutch package is from a 1968 W200 318, hydraulic bell-housing and NP425 that I transplanted into my M37.