190D 5sp popping out of 3rd gear
 

I have got my 190D 5sp almost in perfect condition. Everything works including AC, cruise control and keyless entry. The only issue is it pops out of 3rd during acceleration. It shifts well into third gear but very occasionally will pop out. If I hold/press on the gear stick while in third then it is fine and will not pop out. The throw-out bearing is noisy.

What is wrong, the synchronizser? Drive it the way it is or overhaul the tranny? How easy it is to DIY?

Check and replace the bushings in the shifter linkage. Also a worn out trans mount will cause the shift linkage to not fully engage in the forward (1, 3, 5) gears. The easiest way to check is get underneath the car and have someone shift into 3rd gear then check to see if the shift lever on the side of the trans case has any more travel. You can also adjust the length of the shift rods when appropriate.

Stretch has a teardown thread for a 717.412. If you end up needing synchros, this spring I am going to rebuild my 717.412 and intend on posting pics.

I've had changing the fluid greatly help shifting before in a manual trans, and its just plain good maintenance if you haven't done it. About 2 quarts of dex/Merc ATF. Also you will be able to see how much bronze/brass? comes out when you drain the old fluid to give you some idea as to the health of your synchro.

Thanks for inputs. I will check the bushings first. Never thought of that. The problem is that I have to remove the belly pan which is a pain.

I'd listen to these guys, the only time I've had that happen was a 72 Dodge pickup that someone had tried to rebuild the transmission on, and forgot a spring...