Quote:
Originally Posted by strelnik
While I was sick, a guy working on my car installed another auto trans because the one I had
planned to use no longer would shift into third gear, despite his best efforts. He is very competent.
He proposed to use a 300D non turbo to replace the 240D 722.117.
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strelnik,
I owned, and recently retired a '79 240D with the 722.117, I'm almost
certain. Its <722> on the floor of my shop, so I can double check.
When I bought the car it had a broken tailshaft mounting housing,
which I replaced; so I did a LOT of research, at the time, to ensure the
model number.
I AM certain that I had "your" exact problem after re-installing the
re-housed transmission. I fre-
-aked a bit, thinking it was something I'd
missed in the re-assembly of the governor components.
There are quite a few shuttles and pistons in the tailshaft, and it would
be easy to get it wrong. I fretted.
It would almost never shift into 3rd around the city, winding the old
engines "little heart out". I chased and read every thread
I could find ... and eventually dived into the vacuum system , based
upon that huge thread called something like "
the vacuum system is
the most important part of your transmission" or something like that.
Its 30? pages or so, and been opened a bunch of times. The search
button is your friend
.
It was FIXED by
1) disco-ing the remaining vacuum system parts
so that I could carefuly tune the vacuum dashpot on the fuel
pump to the transmissions shift pattern, and
2) playing with the SIX different possible orifices
in the vacuum line to get the shift point to where I thought it "should be",
and
3) adjusting the governor once the above "profile" had been developed,
4) carefully bringing "other" vacuum components, like the heater, back online;
watching and testing for changes in the transmission's shifting.
Guess what? I found two "new" vacuum problems in the heater circuit!
I must add; the car had a correctly configured vacuum system at start,
with all known leaks plugged. I think that this
disconnecting circuits> action, when combined with aging in the
transmission and vacuum pump, gave RISE to the transmission problem.
The 722.117 was never broken, it just needed a "new state of tune".
The governor works with the vacuum pump, and needs a "timed" rise
in vacuum to enable it to do a "proper" shift.
You can effect this "rise time" by changing the orifices, changing the dashpot
setting, changing the system "loads" of other components -- or ALL THREE!
When I cut the car up to scrap it, replaced by two N/A 300D's, I saved that transmission, as it is the
BEST performer of the three! By merely changing a $2 orifice, I can induce the problem you
currently have .
This understanding came with a fair amount of pain and playing with the system.
This is NOT a reflection on your mechanic; he gets paid, and in most cases, it is
demanded of him/her to "make it like it was -- at the factory".
Rather, it is knowledge gained by gaming the system settings to get the transmission to do WHAT YOU WANT it to do
-- which many mechanics NEVER have the time, or customer patience, to do;
unless they are also an owner of the same vehicle, with similar age and configuration.
Hope this helps.
--frankb