Revving and Sqealing - clutch or tranny? - PeachParts Mercedes-Benz Forum

mbzr4ever · #1 10-30-2011, 04:47 AM

Lately, when starting out in the mornings, shifting from second to third, the engine revs unusually high. Just sometimes, not always, and this is with no pressure on the gas pedal. After the car warms up a bit, problem goes away.

Even more recently, after a long haul down hills (usually in third gear to save the brakes), and after stopping at, say a red light, I shift from first to second, and then to third, I get a loud SQUEAL until I am in fourth gear.

Are these issues related? I just got ripped by a place that charged me to inspect this problem, and their analysis was to get a new transmission for $1400. I kid you not.

This is for my 79 240D, manual tranny.

Stretch · #2 10-30-2011, 05:08 AM

Right so let's get this straight.

You are shifting up from second to third. You push down on the clutch pedal and the engine revs higher but you haven't changed the input on the accelerator pedal?

If so I think you need to clean and lubricate your throttle linkages.

For the squealing - could it be a fan belt? Or is it definitely a gearbox noise?

If so my guess would be clutch release bearing - but check the fluid level in the gearbox first.

fruitcakesa · #3 10-30-2011, 12:38 PM

The 82 will squeal the alt belt on cold mornings and sometimes wet days. I probably have a little oil buildup on mine that makes squealing worse on those wet cold days. It often will squeal through all gears. Eventually it quiets down.

BodhiBenz1987 · #4 10-30-2011, 01:08 PM

Quote:

Originally Posted by fruitcakesa

The 82 will squeal the alt belt on cold mornings and sometimes wet days. I probably have a little oil buildup on mine that makes squealing worse on those wet cold days. It often will squeal through all gears. Eventually it quiets down.

I had the same squeal on my 240D's alt belt for a while ... it turned out the adjustments bolts were too loose and were causing the belt to get looser and looser. Man was it loud on cold days before I fixed it.

mbzr4ever · #5 10-30-2011, 06:02 PM

Quote:

You are shifting up from second to third. You push down on the clutch pedal and the engine revs higher but you haven't changed the input on the accelerator pedal?

Yes,

I'll be cleaning the throttle linkages/alt belt for oil while checking the alternator adjustment bolts.

Now that you mention it, I would hear some squealing sometimes when raining and running over big puddles.

How/where to check the fluid levels in the gearbox (clutch release bearing gearbox)?

leathermang · #6 10-30-2011, 06:32 PM

Also check for missing or stretched return spring on the throttle linkage while you are there lubing it with AT fluid... ( MB FSM )...
Also, in that line of moving things is the pilot bearing on the back of the engine... if you take out the trans for anything be sure to renew that...
The clutch release bearing... usually called ' the throwout bearing ' should be a sealed unit...it is cheap compared to having to go back in to replace it by itself...so put a new one in if you open the system up.... only on old tractors have I seen it with a Zerk fitting...

charmalu · #7 10-31-2011, 11:57 AM

I agree with what is mentioned above, just some cleaning, lubing and adjusting, to start with.

I wonder just where this shop is going to find a "new" 4-spd trans for a 79 240D?

Charlie

Stretch · #8 10-31-2011, 01:41 PM

Quote:

Originally Posted by charmalu

I agree with what is mentioned above, just some cleaning, lubing and adjusting, to start with.

I wonder just where this shop is going to find a "new" 4-spd trans for a 79 240D?

Charlie

I'll get you one if you want Charlie - but the shipping's gonna kill ya!

piccolovic · #9 10-31-2011, 02:05 PM

Also, unpredictable noise like that (a howling type sound, vs. a "Squeal") could be the speedo cable. Squeal would be loose fan belt. Does it sound like a rooster getting it's neck wrung??? If so, that's a loose fan belt.

But does sound like you need to do the basic PM stuff referenced above, and check your fluid levels. On my two manual trannys, the check plug was on the passenger side of the tranny. There is very little room between the car body and the tranny and I had to buy a 30-something hex key (L-shaped) and had it cut down to fit in that tight spot. Then I had to guard that hex key with my life, often refusing to pay the mechanic's bill until that tool was in my hand . . .LOL. It worked for my 5-spd 190D (my first MBZ Diesel) and then my 4-spd, '76 240D. Once you remove the plug, you should be able to stick your finger into the hole, and check the fluid level (should be just below the opening of the hole. If it is low, that is the same hole you would top it off from. The drain plug uses the same hex key and is on the bottom of the tranny. Unless you know exactly what fluid is in the tranny, before adding anything, it might be better to drain all the fluid, and replace it with all new fluid (I think it's like 2.5 L capacity). Then you can be absolutely sure that the fluid situation is absolutely correct.

Let us know your progress, and don't believe the idiots who just want to make $$ swapping out complete components to fix a 10 cent part!!!! Even if the problem is inside the tranny, replacing the shaft bearing inside and replacing the seal is something you could do yourself (with a trip to a machine shop to press on the new shaft bearings) for the cost of the bearings, machine shop bill, and a new seal (worst case scenario would be if you had to pay a mechanic to drop the tranny and do it, also), but would certainly be tons cheaper than to get a "new" tranny. Should you think this is too much trouble . .. I'd be very happy to take this car off your hands . . . LOL.

mbzr4ever · #10 11-01-2011, 12:47 AM

Exactly my point. I don't think they even bothered to lift the hood, and thought they could take advantage of this girl!

This weekend I will try to find the plug (I think I recall doing this once years ago?) to check the fluid. But I didn't know special tranny fluid had to be added or was even needed?

Please, don't laugh at lack of knowledge on this. But at least I can change my oil, every 3K miles and know better than to pay $1400 for a new tranny,

BTW, just drove it 200 miles today, and not a squeal or revving sound. I did give the linkages a blast of some degreaser/lubricant yesterday.

BodhiBenz1987 · #11 11-01-2011, 03:20 AM

Quote:

Originally Posted by mbzr4ever

This weekend I will try to find the plug (I think I recall doing this once years ago?) to check the fluid. But I didn't know special tranny fluid had to be added or was even needed?

When you find the plug, be really careful to clean out any dirt or corrosion in the head of it and make sure the allen bit it seated all the way in it ... so as not to strip it. I don't think MB even lists a specific change interval for the manual trans fluid as with the automatic, but if you're not sure the history of the fluid in there, you might want to change it on principle. I used Mobil 1 ATF in mine and it shifts really nicely; a lot of people seem to prefer Redline MTL and some have success with 10w30 motor oil.
I'd definitely keep looking at the belts if the squeal returns ... even a slightly loose one can make a pretty piercing racket. Hopefully lubing the linkage solved the high revs ... if not, as leathermang suggested, check the little spring at the back of the IP. I knocked mine off once during a valve adjustment and couldn't figure out why my car would randomly rev up to its liking and stay there.

piccolovic · #12 11-01-2011, 03:37 PM

Quote:

Originally Posted by mbzr4ever

Exactly my point. I don't think they even bothered to lift the hood, and thought they could take advantage of this girl!

This weekend I will try to find the plug (I think I recall doing this once years ago?) to check the fluid. But I didn't know special tranny fluid had to be added or was even needed?

Please, don't laugh at lack of knowledge on this. But at least I can change my oil, every 3K miles and know better than to pay $1400 for a new tranny,

BTW, just drove it 200 miles today, and not a squeal or revving sound. I did give the linkages a blast of some degreaser/lubricant yesterday.

YEAH!!!! SCORE ONE FOR THE GIRL'S TEAM!!!!

It's easy enough to find. Get under the car, go to the passenger side, on the passenger side. It will be about halfway up the transmission, across from the transmission hump side of the body. It will be hard to fit the "L-shaped" Allen Key (you can't) unless you have it chopped, at a machine shop. When you find it, clean it out, then fit the allen key, firmly. I had to put mine up on a rack, or jackstands, so I could use a cheater bar to turn the nut, and even that was difficult. BTW, that same allen key will remove the check nut, and drain plug on the rear end, also. Again, use a cheater bar to loosen.

Basically, I put my 240D on a rack at a friend's shop and drained the car from bumper to bumper, and replaced all the fluids. At the time, I put 90 wt. gear oil in the tranny, which it's still running, with no problem. I was not told about ATF by the 800 number folks. I also drained the rear end, and refilled it. Both the tranny and rear end had gear oil in it already, which had changed from amber to slightly burnt brown, indicating it was dirty and needed changing.

I drove the car for three years before selling here in Florida to Pierre, and it's still running around Miami area getting 36 mpg.

We'd love to hear about your car and it's progression. BTW, where are you located?