What do I do about 2nd gear grinding ?

[babyjames]

Full synthetic oil formulated for manual 'boxes. VERY good stuff....

Jay.

[Bill Adkins]

That gear box was designed to run ATC. There is a newer fluid used by MB to eliminate some issues within the gear box. It is clear and I don't remember the name but your MB dealership should be able to answer that question. Gear or hypoid oil is a no no.
Bill

[AlexCole]

Originally Posted by Rafi

My yellow 74 240d (cabbie) manual 4 spd grinds when shifting to 2nd gear. If I wait a second in netural with clutch pressed then shift to 2nd then it does not grind.
My options I think:
1. live with it.
2. fix the transmission if that is possible.
3. change transmission from a recycler.
4. Change transmission oil, will that make any difference ?
5. ??? any ideas ?
Which option makes more sense?
I am thinking of trying option 4 first to see if that makes any difference.

I am not an expert by any means, BUT I have a similar car ('75 240D) that had similar problems, when I first got it. And, Yeah, my manual says to use ATF as well, but Roy (whunter on the forum here) recommended 75W85 gear oil- which unless you live in Australia or Japan is impossible to find. Had some help from my NAPA guy track down some info on it and found the next best thing-- 75W90. Found that the fluid that was in the tranny was probably ATF (red in color and low in viscosity). With the change, I have noticed definite reduction in grinding, especially downshifting from 3 to 2. BTW, it is the same stuff I put in the rear diff. That was ~ a year ago, and no problems. Alex

[Bill Adkins]

I have noticed that many feel the manufacture really doesn't have a clue as to what is supposed to be used in there products. Probably unlike many here on this forum I have rebuilt these gearboxes, the reason the gears clash is because the blocker rings/ syncro rings are worn and no longer function as designed. They are supposed to match the gear speed with light friction contact from one throw to the other on the slider when shifting gears. The proper resolution is to r/r, d/a and replace the blocker rings. The gear box is designed to run with thin fluid as clearances are closer then most Farm All tractor gear boxes. I believe they used saw dust in American Graffiti but thats probably not the best bet. As for fluids it probably wont be an issue to experiment as the wear has already happened. Good Luck
Bill

[Bill Adkins]

An addition, I just did a search on this site and the part number is 000 989 26 03. That's through MB and not Car Quest. Search for Fluids and Lubricants, it lasts all approved fluids for the car.
Bill