Manual Transmission noise

[johnk]

Hello everyone,

I purchased my 68 280sl with a manual transmission two weeks ago. When I test drove it I immediately noticed the mid level whine after I shifted and while stepping on the gas. The noise goes away after you get up to full speed in each particular gear. and seems directly proportionate to the stress on the transmission after shifting. This was my first ride in one of these cars so I am not 100% certain how it should sound, but it reminded me of when I last drove a car from the 30's.

The noise is definitely noticeable. Even my sister-in law wondered how old the car was after shifting it. Any ideas if this could be the throw-out bearing or something else other than its been too long since I drove a car from the 60's?

Thanks
JohnK

[johnk]

Sorry forgot to add:

The transmission shifts smoothly and doesn't appear to make any other noises. I have not checked or replaced the oil yet but plan on doing that this weekend. It may be a while before I can drive it again to see if new oil helps so I thought I would pose the question to the forum first.

thanks
Johnk

[George Des]

Just make sure you are running ATF and not regular gear oil. Yes, the manuals use automatic transmission fluid not gear oil.

[George Des]

Just make sure you are running ATF and not regular gear oil. Yes, the manuals use automatic transmission fluid not gear oil.

[ja17]

These transmissions are usually very smooth and quiet. Most likely low on fluid or a damaged bearing.

[johnk]

Thanks Joe,

I will start with replacing the ATF. If it is a bearing, do you think it would be the throw-out bearing? I guess I will see if I have to pull the transmission.

John

[jeffc280sl]

I don't think noise from the throughout bearing is subject to the kind of loads you describe.  It engages and disengages the clutch plate.  It is under load so to speak when doing these functions.  Once the clutch is engaged there should be no particular load to cause noise. 

I rebuilt my manual transmission.  There is lots of help here if you decide to go this route.  Challenging job.  I remember getting something wrong and it would not stay in third gear.  Had to tear it all down again and start over.  It is perfect now. 

[johnk]

Thanks Everyone. I am sure I will have more questions if changing the ATF does not work. Any recommended type of ATF?

John K

[ja17]

Dextron or its replacement seems to be the most widely used. Probably not critical on the standard transmissions as long as it is ATF.