Really dumb question from a stick newbie - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 01-21-2010, 01:05 AM

... What does a slipping clutch feel like? I'm pretty sure I'm experiencing one in the 240D on the highway. It'll just be going along fine and then it will sort of hiccup as if losing traction. I only notice it in 3rd and 4th. My first thought was fuel filters, which I'll change anyway, but it seems a little more like the engine is creating power but not getting it to the wheels all the time. Please enlighten me on the nature of clutch slippage.

Fulcrum525 · #2 01-21-2010, 01:06 AM

I was about to say....you are by no means a newbie....but i'll let this one pass as i'm not that good at driving stick either

BodhiBenz1987 · #3 01-21-2010, 01:22 AM

Quote:

Originally Posted by Fulcrum525

I was about to say....you are by no means a newbie....but i'll let this one pass as i'm not that good at driving stick either

Well ... I'm new to clutch failures.

which is surprising considering given this poor car's history. LOL.

Diesel911 · #4 01-21-2010, 01:23 AM

When it hiccups does the Engine rpm go up?

I had an experience on a non-Mercedes where due to a leaking Rear Main Bearing Seal Oil had saturated the Clutch Disc. When it slipped the rpms when up and my speed went down. It slipped more in the higher gears.

My other experience was with the Volvo Diesel. The Clutch would slip momentarily right after releasing the clutch pedal. Would slip a little and then be Ok. In that case the everthing including the Clutch Disc was worn. New Clutch, Flywheel re-ground and New Clutch Disc fixed it.

BodhiBenz1987 · #5 01-21-2010, 01:34 AM

Quote:

Originally Posted by Diesel911

When it hiccups does the Engine rpm go up?

I had an experience on a non-Mercedes where due to a leaking Rear Main Bearing Seal Oil had saturated the Clutch Disc. When it slipped the rpms when up and my speed went down. It slipped more in the higher gears.

My other experience was with the Volvo Diesel. The Clutch would slip momentarily right after releasing the clutch pedal. Would slip a little and then be Ok. In that case the everthing including the Clutch Disc was worn. New Clutch, Flywheel re-ground and New Clutch Disc fixed it.

I don't really notice the rpms going up suddenly ... it sort of feels like the rpms hold steady but the power to the wheels flutters. The car doesn't leak an oil externally but I guess that doesn't mean it isn't leaking any into the clutch.

It doesn't seem to slip right when I release at all ... it shifts nice and easy. It does it while I'm already rollin' along.

jt20 · #6 01-21-2010, 02:49 AM

if you can recreate the problem, there's a good chance it could be the clutch.

I had a Supra that would something very similar. When the engine was hot, I could slip in 3rd or 4th by going up a hill and putting the pedal to the floor. Try putting the greatest engine force against the most secure rear-wheel friction... if it doesn't slip, you're golden.

if the hiccup occurs randomly, consider the fuel system, primarily injectors or water in the fuel system.

DeliveryValve · #7 01-21-2010, 03:28 AM

There is a test you can do to see if your clutch is shot.

With the engine running and the car parked.

Apply your parking brake, depress the clutch pedal, shift the trans into 4th, and slowly release the clutch while pressing the fuel pedal. If you are able to release the clutch fully without it stalling the engine (while still pressing the fuel pedal), then you have a problem with your clutch.

The other thing you might want to check is your motor and trans mounts. Sometimes the engine and trans can move out of place and cause the clutch linkage to not be aligned correctly. Which can cause the clutch not be fully engaged.

Other than that, then the fuel system as noted earlier.

.

layback40 · #8 01-21-2010, 05:12 AM

When you change from 3rd to 4th on an up hill grade, if you keep the power on and it flares as you take your foot off the clutch, its a good sign of a slipping clutch, could need a new clutch plate or pressure plate. The slipping tends to get worse over time, say 10k miles. eventually when you put your foot on the gas hard in 4th gear, the engine will rev without increasing road speed. its a lot like flaring with an auto.

Eric · #9 01-21-2010, 07:38 AM

a slipping clutch feels like you dove over a patch of ice and lost traction.

C Sean Watts · #10 01-21-2010, 08:27 AM

Like Eric said, "drove over ice and lost traction." - good way to put it.

OR, you shift just fine, let the pedal out, get on the throttle - the engine revs but you do not accelerate.

TEST:
Go out on an uncrowded road. Start out from a dead stop normally - 1st->2nd-> over shift to 4th (truckers call it 'progressive shift') and give it full throttle. If the engine revs faster than you accelerate = clutch slip.

BodhiBenz1987 · #11 01-26-2010, 07:04 PM

OK, little update. I didn't drive the car this weekend due to travel and bad weather. I had to drive it today because something was burning on the van I borrowed.

Observations:
-It is much worse when cold and much worse on hills. It feels as if the power is fluttering, if that makes any sense.
-The car stalls out when I do the test DeliveryValve mentions
-There doesn't seem to be slippage when I downshift from 4th to 3rd, or 3rd to 2nd, flat or on a hill ... I get a nice immediate increase in "power"
-I know this sounds odd, but I really can't tell if the engine is revving faster or slower when I get the slipping sensational ... kind of an aural illusion thing.

It sounds like it might be stuttering a little but the exhaust makes some ugly noises so it all blends together.
-I just got my new primer pump today so when it stops sleeting I'll change all fuel filters just in case that's all it needs. Wouldn't that be nice?

Shawn T. W. · #12 01-26-2010, 08:15 PM

Notice any funny smells?

A clutch slipping is really burning . . . smells worse (or about the same) as smoked brakes!

If your clutch was slipping, and put more fuel (Not gas!) to the engine, it would not stutter or shake . . . it would wind up as you slow down . . . by keeping you foot in it, the clutch will not grab and then release (slip) back and forth quickly if you keep the fuel pedal down.

I don't think it is your clutch.

BodhiBenz1987 · #13 01-26-2010, 08:42 PM

Quote:

Originally Posted by Shawn T. W.

Notice any funny smells?

A clutch slipping is really burning . . . smells worse (or about the same) as smoked brakes!

If your clutch was slipping, and put more fuel (Not gas!) to the engine, it would not stutter or shake . . . it would wind up as you slow down . . . by keeping you foot in it, the clutch will not grab and then release (slip) back and forth quickly if you keep the fuel pedal down.

I don't think it is your clutch.

It might just be the engine dying ...

Poor car. Although I'd think if the compression were that bad, it wouldn't start at 10 degrees out. Guess I'll figure it out eventually ... it probably wouldn't hurt to do the tank strainer too.

Junkman · #14 01-26-2010, 08:59 PM

You would know it if the clutch was slipping when starting in 4th. A slipping clutch has nothing to do with the engine hiccuping. You can force it to slip by getting on the go pedal & pressing the clutch. Engine will rev without wheels going faster. Check fuel delivery for cause of loss of power.

BodhiBenz1987 · #15 01-26-2010, 09:35 PM

Quote:

Originally Posted by Junkman

You would know it if the clutch was slipping when starting in 4th. A slipping clutch has nothing to do with the engine hiccuping. You can force it to slip by getting on the go pedal & pressing the clutch. Engine will rev without wheels going faster. Check fuel delivery for cause of loss of power.

Thanks. I'll change the filters and report back, then work from there. I guess it could also be an injector.