240D transmission doesn't upshift

[pdrayton]

I just bought an 1983 240D for next to nothing and would be most appreciative if anyone can help me with these problems I'm having.

The engine runs fine (slight knocking though), but the transmission shifts rough, and will only upshift if you release the accelerator. So you have to floor it and then take your foot off the gas to make it shift. Then it shifts pretty hard.

I've been reading up in the forums about tuning the tranny. My benz has a replacement tranny from a scarpyard. Anyway, I read that the vacuum system has to be working before bothering with any other tranny adjustments. So I started working on that and am completely confused. It looks to me like there are vacuum hoses missing. Could this be the cause of the tranny not wanting to shift?

I've attached some photos of the vacuum system to show what's there and what's not.

If there are tubes missing, can you tell me what they are and how to fix or where to get a schematic and fix it up?

I've bought a vacuum gauge. Just a gauge, no pump. Is it worth spending the extra $50 to get the Mityvac kit, or can I make do with just a vacuum gauge?

Lots of questions all at once, I know! I'm really excited to get it going well so I can start making biodiesel. Answers to any of the questions would be great.

Also, an aside, do you know the size of the main crankshaft bolt? Is it a 22mm? It's almost impossible to get a socket in there, let alone look as to what's going on. I'm going to probably replace the rod bearings to take care of the knocking and will have to turn the crankshaft to get to them. I'm new to diesels, so I don't know if the noise is a rod knocking or 'nailing'. I can attach a sound file if that will help. Thanks.

Awesome forum - feels like a great big MB family!

[miktvk]

I have recently been doing my own 240D-300D diesel research, and it looks to me that you have quite a few bits missing. Check out:

http://dieselgiant.com/mercedes_diesel_maintenance_tips.htm

http://mercedesdismantlers.com//diesel_vacuum_system#Diesel%20Vacuum%20System%20Troubleshooting

do a Google search on 240D as well. Something to think about is setting up a consumer account on AllData.com, its poorly structured, but I have been able to get some reasonably helpful info for our wagon, including diagrams.

[DieselJim]

Sounds like you have a lot of fun. Look on the diesel forum too for info. Lots of experience around. You might have a kickdown switch issue also. Take up the floor mat and unplug the kickdown switch. If it now upshifts that was the problem.