Hey guys-

This car runs great. If I take the car out after not having driven it for a couple days it runs flawlessly. However, after I have driven around doing a few errands, it begins to let out this ear-peircing high pitch squeal whenever I step on the accelerator. But if I had no ears, I would never know based on how it acts normal in all other ways while it makes this sound. Months ago, it only made the sound as the car was about to switch from first to second gear (after I drove it around doing some errands for a while), but now after it's been running for a while it does that whenever the accelerator is depressed.

Anyone ever had this problem? My car is a 1975 300D

 

When it makes the squeel is the A/C on?

 

Nope. No A/C or fan is running. I really want to say I feel like it's coming from the transmission, but like I say, the car performs perfectly fine other than the fact of this racket. Thanks for your interest in my problem.

 

It makes the nosie while in motion only? Does it make the noise while in park or neutral as you accelerate?

 

It's only when I'm in drive. It's as if it's coming from the transmission or something. I feel like this high pitch sound starts just right before the gears are about to switch. Hope that helps.

 

Mine (83 240D) does that too, I can hear right before it switches gears. And only right before it switches gears.

It also shifts pretty rough, I was going to check/change the tranny fluid and see where that got me, but I don't really have any idea.

 

Please check to make sure my wife and kids are not in the back seat. I'm used to the high pitched squeal but it may take you some getting use to.

 

My 300D just did this for the first time yesterday. Only in the higher gears though, once I was back in low gear the noise went away. It was after I had driven the car more than usual in a day as well. Like you said the car runs fine, not overheating or anything else. It seems to me that the noise is coming from the stearing column, as mine shifts perfectly fine. If this persists I will probably take it to my mechanic and see what he reccomends.

 

How do you fix it if the car does squeal when the A/C is on? I've been using wd40 and it works for about a month before it comes back...

 

So I finally broke down (figuratively) and brought the car into a mechanic. As it turns out, when I installed a new alternator, the I switched out the wheel that the belt turns on it. The old one was a one-peice, the new one came in 2 halves that created the wheel when the bolt was tightened down to sandwich them together. Unfortunately, with my lack of air tools, I couldn't tighten them together enough, so when the belt was turning them fast enough it was spinning them to make this gawdaweful sound. So lets recap:

Time I spent trying to figure it out: all-summer-long
Time mechanic spent, cost for his services: an hour, $95
Feeling like a dork: priceless