Transmission downshift clunk - Page 2 - PeachParts Mercedes-Benz Forum

Hit Man X · #1 03-23-2010, 09:11 PM

This may be of use:

http://www.peterschmidtransmission.com/vacuum/1977_1985/617_95/1981_1984.jpg

toddyvol · #2 03-23-2010, 09:22 PM

Quote:

Originally Posted by Hit Man X

This may be of use:

http://www.peterschmidtransmission.com/vacuum/1977_1985/617_95/1981_1984.jpg

Thanks..That's extremely helpful.

Hit Man X · #3 03-23-2010, 09:47 PM

Just print it and blow it up. Then mark out what is not needed... i.e. EGR system, switch over valve, etc. The emissions stuff basically.

Keep it in your file, so you can revert back if necessary or just so you know what you did, how, when, where.

Purchase a MityVac as soon as you can. They are fairly inexpensive and invaluable when fixing these vehicles. I forget where I purchased mine, but it was reasonable enough even if I only had one of these vehicles.

My SD used to have this issue, I fixed many things at once so it is hard to say what fixed it exactly. I replaced all my three and four way connectors under the hood as well as the small rubber vac tubing lines all over. I did have leaking HVAC vacuum pods 'whunter' pointed out to isolate to test, these are easy to replace and not too cost prohibitive. They are the three in the behind the glove box area.

Another member pointed out the door lock system, early 126s from my memory did not have electric pumps like the later ones. So isolate that and just work your way through the vacuum system.

toddyvol · #4 03-23-2010, 10:02 PM

Quote:

Originally Posted by Hit Man X

Just print it and blow it up. Then mark out what is not needed... i.e. EGR system, switch over valve, etc. The emissions stuff basically.

Keep it in your file, so you can revert back if necessary or just so you know what you did, how, when, where.

Purchase a MityVac as soon as you can. They are fairly inexpensive and invaluable when fixing these vehicles. I forget where I purchased mine, but it was reasonable enough even if I only had one of these vehicles.

My SD used to have this issue, I fixed many things at once so it is hard to say what fixed it exactly. I replaced all my three and four way connectors under the hood as well as the small rubber vac tubing lines all over. I did have leaking HVAC vacuum pods 'whunter' pointed out to isolate to test, these are easy to replace and not too cost prohibitive. They are the three in the behind the glove box area.

Another member pointed out the door lock system, early 126s from my memory did not have electric pumps like the later ones. So isolate that and just work your way through the vacuum system.

Does vacuum hose size matter? The hard vacuum line going to the transmission looks rather small diameter wise. A little bigger than pencil lead.

Hit Man X · #5 03-23-2010, 10:16 PM

Quote:

Originally Posted by toddyvol

Does vacuum hose size matter? The hard vacuum line going to the transmission looks rather small diameter wise. A little bigger than pencil lead.

The rubber end stuff is what I replaced, that harder line I simply left alone. It should be around 3.5mm ID.

I think I have about 50m of it around, do not ask how it happened

. If you want some, just PM me.

toomany MBZ · #6 03-24-2010, 12:13 PM

Yeah, you may even find the hole the old one went through. Hard to see/get to tho, it's under a bunch of lines at the firewall. It's just a vent that draws clean air from the cabin.