722.118 first gear only - PeachParts Mercedes-Benz Forum

nscarr · #1 07-06-2007, 04:27 AM

stuck on vacation, in a good place but will need to get home eventually...

1980 300d with a 722.118, was going to replace transmission (till i found out my parts tranny, a 722.120, wasn't compatible) and did some vacuum work (now vacuum profile is nice) and now it won't get out of first gear. i found some similar situations on the forum, but could use some help:

is the kickdown switch controlling the solenoid?
are valve bodies accessible to clean, and how?

gracias in the mucho amounts,
-noah

nscarr · #2 07-06-2007, 02:26 PM

i've checked the solenoid for the kickdown switch and it looks like a resistance of ~15 ohms between the switch screw and the body. anyone know if this is a characteristic? (my parts solenoid had infinite resistance.)

nscarr · #3 07-06-2007, 02:39 PM

i've talked with a couple of shops here in eugene, oregon, and they've recommended investigating a plugged valve body. anyone have some sage advice before i dig in? thanks a bunch!

kerry · #4 07-06-2007, 02:56 PM

Have you tried unplugging the kickdown switch to see what happens?

mtldieselguy · #5 07-06-2007, 03:05 PM

I would strongly suggest taking the kick down switch off the car, and going crazy with contact cleaner. Saved me a transmission! (thanks to the guys on this forum

nscarr · #6 07-06-2007, 03:55 PM

hiya, thanks for the replies.

yes, i've tried disconnecting kickdown switch and same first gear only. i put in a different solenoid body, too, in case my original wasn't functioning. i'm a little curious how the switch works--i assume a current passes when it's activated and this current then pulls out the solenoid so the valve opens--is this about right?

i need to get some atf and will check for clogged valve body.

kerry · #7 07-06-2007, 04:08 PM

A number of people here have praised the wonders of TransX. Since you are on vacation, and I assume a lot of transmission work is a pain in the neck, I'd give it a try.

nscarr · #8 07-06-2007, 04:38 PM

well, i'm at my dad's house, and he has a great shop--far better than working on the dirt at my house. but i will need to get back to seattle for monday. would the trans-x be an additive or would i add it, run it, and drain it?

kerry · #9 07-06-2007, 04:40 PM

Quote:

Originally Posted by nscarr

well, i'm at my dad's house, and he has a great shop--far better than working on the dirt at my house. but i will need to get back to seattle for monday. would the trans-x be an additive or would i add it, run it, and drain it?

It's an additive i believe. I've never used it myself but over the years there have been a number of testimonials on here.

nscarr · #10 07-07-2007, 03:52 AM

well, i've cleaned out the valve body, cleaned up the kickdown solenoid and still have only first gear. it'll go into second if i'm headed downhill and i let up and stomp on the accelerator a few times. i have some pictures of the valve body cleanup/reassembly if anyone's interested. not sure i cleaned out the valve body in the "correct" kind of way, but made sure all valves were functional and not sticky. i'll fiddle with it some more tomorrow.

rs899 · #11 07-07-2007, 06:49 AM

If the valve body is clean, I would start thinking there is a pressure problem elsewhere. Does reverse work?

The lousy ATSG manual states for transmission does not shift beyond second gear " 1. Selector sleeve detached , or 2. Command valve jammed or 3 Governor pressure too low"

Rick

nscarr · #12 07-07-2007, 12:37 PM

Quote:

Originally Posted by rs899

If the valve body is clean, I would start thinking there is a pressure problem elsewhere. Does reverse work?

The lousy ATSG manual states for transmission does not shift beyond second gear " 1. Selector sleeve detached , or 2. Command valve jammed or 3 Governor pressure too low"

Rick

thanks rick, for the atsg info. reverse is working. at this point, i'd try voodoo to get it going. i'm quite the beginner mechanic, so if you have any insight how to correct any of #1-3 it'll be less voodoo magic. -noah

rs899 · #13 07-07-2007, 02:36 PM

I would think that you have covered nos 1 and 2 already. That leaves #3, and if ATSG is right, you will be pulling the tranny.

Rick

nscarr · #14 07-07-2007, 04:38 PM

Quote:

Originally Posted by rs899

I would think that you have covered nos 1 and 2 already. That leaves #3, and if ATSG is right, you will be pulling the tranny.

Rick

hmmm.... trans pulling is no longer in the schedule for this trip. i will continue to fiddle and fuss with vacuum; the trans worked decent (slips and flares, tho) on the way down here, then adding missing vacuum parts caused the no-upshift condition. this particular transmission appears to be completely controlled by vacuum. on my donor 722.120 (not installed because incompatible w/o electrical mods, thank you, rick, for your previous info on this) there exists the linkage from the throttle on the valve cover down to the transmission's passenger side throttle-linkage. on my 722.118, this throttle linkage on the passenger's side of the transmission is not there--two theories on this, either the trans is completely controlled by vacuum or during some previous trans work this part was omitted (?). thanks a bunch, and i'll post with results later. -noah

nscarr · #15 07-08-2007, 05:20 PM

on a whim, i changed out the vacuum modulator, removing the 722.118 (red) modulator and installing the 722.120 (white). i now have my gears back--heading back to seattle, will post more if troubles develop. thanks again for the help. -noah