ominous click when throttle applied 1983 240D 4 speed - PeachParts Mercedes-Benz Forum

JB3 · #1 03-13-2014, 09:54 PM

Curious if anyone has any insight on todays odd noise issue. Driving around my 83 240 4speed like normal, and its developed a pretty loud clicking noise every time you apply the throttle in gear, like if you are coasting in gear, then give it some throttle, there will be a loud single click, and nothing else.

There is no performance loss, but it definitely sounds like play in something. It sounds like its coming from the center of the vehicle.

I've seen some pics of worn output shaft splines on a 4-speed, and I'm curious if this might be consistant with that issue, any insights?

(I also installed annular empi axles about 1000 miles ago, but everying about these seem nice and tight

Stretch · #2 03-14-2014, 03:52 AM

Definitely sounds like some play in the drive line - but if you can't feel any wiggle in the axles or the propshaft could it perhaps be a speedometer problem?

Pretty simple check for the speedo - disconnect at gearbox, plug it with something and then go for a drive (sorry ocifer me speedo don't work cause I'm trying to detect a click)

gatorblue92 · #3 03-14-2014, 07:19 AM

Its only a noise and you can't feel anything when it happens?

Zacharias · #4 03-14-2014, 03:55 PM

Check to make sure the fan shroud is locked in place properly.

How old are your motor mounts? If a mount has let go, the motor may be moving enough when you give it throttle, that the fan blades contact the shroud briefly. This doesn't necessarily generate the sound you might expect from such contact.

JB3 · #5 03-14-2014, 06:10 PM

Quote:

Originally Posted by Stretch

Definitely sounds like some play in the drive line - but if you can't feel any wiggle in the axles or the propshaft could it perhaps be a speedometer problem?

Pretty simple check for the speedo - disconnect at gearbox, plug it with something and then go for a drive (sorry ocifer me speedo don't work cause I'm trying to detect a click)

worth trying, doesn't feel like its speedo related though. More and more I am feeling like it might be coming from the right rear. Could be related to the axle after all maybe. Haven't had a chance to jack it up yet and play, hopefully this weekend

JB3 · #6 03-14-2014, 06:11 PM

Quote:

Originally Posted by gatorblue92

Its only a noise and you can't feel anything when it happens?

Just a big metalling click noise, but you can't feel anything in the way the car drives. Performs in its same old stodgy way, puttering here and there without hurry

JB3 · #7 03-14-2014, 06:15 PM

Quote:

Originally Posted by Zacharias

Check to make sure the fan shroud is locked in place properly.

How old are your motor mounts? If a mount has let go, the motor may be moving enough when you give it throttle, that the fan blades contact the shroud briefly. This doesn't necessarily generate the sound you might expect from such contact.

The motor mounts are unknown and on the eventual list (dont look bad though), but this car has no fan shroud. Some months back it had some kind of chemical reaction with a long term coolant leak out of the top of the radiator (since replaced), and the shroud became as soft as inner tube rubber in about an 8 inch section of the top. It drooped down into the fan and was chopped badly, so I got rid of the whole thing

JB3 · #8 03-23-2014, 07:53 AM

So update-

Click got louder and louder, and started happening when the throttle was engaged, and when the throttle was let off. I put the car on a lift and went over it carefully, and no smoking guns. Nothing loose, nothing leaking or worn. Perplexing, and im pretty sure it was coming from the passenger side annular axlei installed recently.

Flash forward to yesterday, was coming back from the airport dropping someone off, when i found myself right behind a 124 chassis diesel. I couldnt let this guy leave the 240 in the dust, so decided to pass him to show him the old codger still had it. He gave chase and i topped out at about 85mph for a minute or two before he stopped toying with me and left the highway. Now that the 124 youngster was gone, i reduced speed to a more sedate 65, more in keeping with the 240s dignified station in life.

I got off the highway and the click was gone, as of today hasnt come back yet. Maybe all the drivetrain needed was 5 minutes at WOT.