Let me take this pint by point.
Mark said: "There should be a pivot point on the top of the cam cover, and the L-shaped arm that pivots there assures that the movement at the transmission is not linear with the movement of the throttle rod."
Bogy replies: All the stuff on the original cam cover is not here because this engine came out of a different car than the tranny.
Mark Said: "In fact, the transmission shift rod moves very little. This is from the W116 service manual:
http://handbook.w116.org/Engine/617/30-300.pdf"
Bogy replies:
The picture on page 300/5 looks like the pressure control rod (which I have been calling the kick-down rod) has a slotted end and only moves at the very end of the throttle movement. is this the case? If moving it "linearly" as it were, with the throttle travel is wrong I can build a slotted end to emulate that fact.
Mark Said: "Shifting as you've described is largely caused by mis-adjusted kickdown linkage, and/or defective vacuum modulator, if equipped. It could also be due to dried out and leaky servo seals, especially if there is a delay in shifting into reverse, which is the first to go."
Bogy replies: I think this is a pressure control rod and not a kickdown linkage as I have been calling it. Please correct me if I am wrong. As for reverse - you need to have your foot firmly on the brake when it goes into reverse or you WILL hit something behind you. it goes into reverse fast, firm, and strong.
Mark Said: "I would certainly look into using the TH400, or, even better, 700R4. Best would be the Aisan from a 4.0 Cherokee or TJ, if you don't mind shifting it yourself (the transmission control module needs inputs from the engine that these old diesels don't provide). The gearing in the Aisin is much better suited to the OM617A torque curves than the GM transmissions. There are several little backyard machine shops selling kits to mate any of these transmissions behind the Mercedes diesels. In the long run, spending $1000 - $1200 on a kit would cost not much more than getting a divorced transfer case set up, and save a LOT of trouble."
Bogy replies: And I would prefer a 700R4. But I am on a tight budget here, (I am into this thing less than $1100). The TH400 and t20 came with the jeep so until better times I have only that as an option. But it is very appealing as the tcase is married to it. As for TJs or other jeep trannys, I have a right side drop tcase and front axle. Most of the jeep stuff I have seen is left drop. As for machine shops - I keep some very accurate and precise but aging german machines (Deckel FP4A) working for a local machine shop and they let me use them whenever they are idle, Saturdays mostly. In three hours I could have my own adapter plate made. Again, I am on a budget here. But for me the journey is the destination. Doing it is a big part of the joy for me. Being done is great, but only part of the fun.
All that said thanks for the attention. If you can clarify how the pressure control rod is supposed to move that would be really great. Meanwhile I would like to save this tranny if I can. 4 speeds are better than three. But an easy transfer case solution trumps that.
Bogy.
"Hardware eventually fails.
Software eventually works"
- Michael Hartung
From: "'Mark in Lakewood, CO' beeser750@q.com [diesel_mercedes]" <diesel_mercedes@yahoogroups.com>
To: diesel mercedes <diesel_mercedes@yahoogroups.com>
Sent: Tuesday, July 21, 2015 8:51 PM
Subject: Re: [diesel_mercedes] 4 bolt tranny throttle linkage and shift issues 722.118
The 4-bolt pan trannys don't have the B2 servo piston problem. They have plenty of their own set of problems....
There should be a pivot point on the top of the cam cover, and the L-shaped arm that pivots there assures that the movement at the transmission is not linear with the movement of the throttle rod. In fact, the transmission shift rod moves very little. This is from the W116 service manual:
http://handbook.w116.org/Engine/617/30-300.pdf
Shifting as you've described is largely caused by mis-adjusted kickdown linkage, and/or defective vacuum modulator, if equipped. It could also be due to dried out and leaky servo seals, especially if there is a delay in shifting into reverse, which is the first to go.
I would certainly look into using the TH400, or, even better, 700R4. Best would be the Aisan from a 4.0 Cherokee or TJ, if you don't mind shifting it yourself (the transmission control module needs inputs from the engine that these old diesels don't provide). The gearing in the Aisin is much better suited to the OM617A torque curves than the GM transmissions. There are several little backyard machine shops selling kits to mate any of these transmissions behind the Mercedes diesels. In the long run, spending $1000 - $1200 on a kit would cost not much more than getting a divorced transfer case set up, and save a LOT of trouble.
Mark (now in Centennial, CO)
From: "Aleph93 aleph93@ca.rr.com [diesel_mercedes]" <diesel_mercedes@yahoogroups.com>To: "diesel mercedes" <diesel_mercedes@yahoogroups.com>Sent: Tuesday, July 21, 2015 10:58:29 AMSubject: Re: [diesel_mercedes] 4 bolt tranny throttle linkage and shift issues 722.118 Bogy,
Question, did you drive the parts car before mounting the engine/tranny in the jeep?
If so, it it act the same at that time?
Has the fluid and filter been changed recently?
Heres' the article regarding the B2 piston:
http://articles.mbz.org/transmission/b2/why/ Broken springs in the tranny, can cause the tranny to shift poorly. Mine had a few broken springs, and had shifting problems at 2-3, so I had the local MB tranny guy put in a shift kit for the tranny. Helped a lot. Also adjusting the vacuum modulator etc.
Rob
'85 300D (722.416 CA '85)
Garden Grove, CA
=
Guys:
Last sumer I got an 81 CJ7 for a great price. It got better when I sold the bits I didn't want. It came with a th400 and t20 transfer case. I got it because I wanted a jeep and especially wanted to put the engine/tranny from my parts car in one. A couple of months ago I got it legal and have been driving it. It is the 722.118 four bolt with the long arm for throttle position sensing/shift point modification. The tranny came form a different car than the engine did and I do not have any good details about how to connect the "modulator" arm to the throttle so I made a linkage of my own and it moves the rod "linearly" with the throttle.
Question 1: is this right or should the modulator arm only move at the end of the throttle travel.
It has never shifted right - flaring between 2 AND 3, AND THEN SHIFTING ABOUT 25 - 30 mph DEPENDING ON TEMP. (Excuse the caps, I'm not retyping all that.) As of a few weeks ago it would not shift out of second gear when cold unless I got it up to the mandatory shift point as indicated on the speedo. But once it warms up it shifts in an acceptable manner. Once warm it stays in second a bit too long for my taste and still can flare if I don't dance on the throttle just right. But I can live with it.
Question 2: Because the shift starts working right when warm I suspect some gum or varnish in the valve body (or maybe the band servos - who knows) and when it warms up the stuff softens up and allows acceptable shifting again. I was thinking about using a bit of MMO or something to dissolve the sludge (if indeed that is what it is) and wanted you guys' take on all this.
I may just end up putting the TH400/T20 on because I have it and can make an adapter plate to mount it all onto the engine. And then I would have 4 wheel drive without having to figure out how to install a divorced t-case. I'm just looking at options right now. But any thoughts would be outrageously appreciated.
FWIW, I have mounted a 123 instrument cluster on the dash and the odo doesn't work. But using my phones GPS over a full tank of gas I get just under 20 MPG. (3.54 diffs and 33 inch tires add up to 15% faster than the spedo indicates.) Oh yeah The engine is old and tired. A couple of HARD Italian tune ups has helped it to idle smoothly within 30 seconds after start up instead of 30 minutes. And I can't get it to start unless the injection timing is retarded to about 15 degrees BTDC. (spent all day today proving that.) But it's mine, it didn't cost me much and I enjoy the hell out of bonking around town in it. It was a lot of fun to build. And it is still a lot of fun to work on. There's a thousand little things to do.
Still I gotta do something about the tranny shift thing.
TIA.
Bogy.
"Hardware eventually fails.
Software eventually works"
- Michael Hartung