Today I Noticed My 1980 300d Does Not Have A Vacuum Dashpot On It. Like Alot Of Guys I Can't See The Forest Through The Trees Sometimes.
I've Had It For Almost A Yr Now. It Does Shift Late Etc. Should I Put A Dashpot Or Do Some Not Have One. Ray M.

I own a 1980 300D. Had it for 22 years.

My transmission did not shift very well and I replaced the 3 way
vacuum valve on the valve cover (after testing it and finding out it leaked).
If your does not leak but the little arm is worn off, replace the little arm.

Regarding the dashpot, are you referring to the under the hood part
right off the IP ? I'll take a look on mine and see how that is hooked in.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

Thanks for your reply I'm going to pull the 3 way vac valve on the valve cover to check the vacuum and the arm condition on my day off Mon. Please check yours for the dashpot if you would that is right off the IP. I hear so much about it's control but my 80 300d has none. They had alot of work done on it prior to my purchaseing it and i wonder if the Bozo could have left it out. thanks Again.

I share your interest in whether or not a Vacuum DashPot might improve the tranny shifts on both my Son's 1980 300D and my 1980 240D. In looking at my favorite resource for vacuum diagrams [a tranny rebuilder here in CA with more than 30 diagrams on their WebSitewww.PeterSchmid.Com] ...in looking at their diagram(s) for the 1980 300D models with the 617.912 engine, [ http://www.peterschmid.com/vacuum/1980/617_912.jpg] no DashPot is shown but I still think there is merit in the notion that this device might help to retard the 1-2 and 3-4 shifts.

I say this because this same WebSite also [in my opinion ambiguously] shows a diagram for "1977-1985" models with "617.91" engines [ http://www.peterschmid.com/vacuum/1977_1985/616_617_91/616_617_91.jpg ]. This last diagram has a "mechanical... Switchover" valve and plug that clearly our 300D and 240D do not have so I have tended NOT to use it for our cars.

So I still see the DashPot as an add-on that might retard shifts whereas your description of your problem seems to be the opposite. Maybe we are really talking about the same thing but just not saying it the same way... it's happened before. If your description is accurate about having late shifts, then you need to check out my recent POST at: It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ.... There is much controversy about the subject of how best to set up the vacuum control systems that control the automatic tyrannies on these vintage MBZs. At least for some of the earlier models, I think these systems are relatively simple once you have the right mindset about quantifying the vacuum energy source just as you would positive air pressure.

Take a look at my references above, see what you think, and then throw in your own 2 cents worth into the fray! I will soon purchase a DashPot and play around with it on my two 1980 models ! They can be found for less than $5.00 !
Sam

Hi,
my tranny shifts just fine. Im not sure it even has that dashpot.
The link you sent me is coming up server not found.
My car wouldn't shut off this AM. I needed to give it a little bit of throttle and then it will shut down.
Dave