Ginny's 78 300SD, looking for working servo
 

Okay, the baby girl is at the shop.
So far, they found a block heater (yeah, I didn't know it had one, kick me)
and they are parking it outside plugged in to see if it works.

The lack of heat, they say 90% of the time is the servo. Anyone got a servo, working and the amplifyer that goes with it? The mech says that I would need to replace both as it's the amplifyer that goes out and causes the servo to burn out. Everyone, anyone agree with this?

Lack of Reverse, they say they didn't find at Reverse Band Adjustment on my tranny. I'm not sure they know that some trannys have this, though they have been working on MB for 47 years. I'll look at the tranny myself when I have the brakes checked. The brakes place lets me hang around and watch when they work on our cars. I know what I'm looking for and they may not since they aren't a tranny place.

At least the oil got changed with out incedent!

That's what my indy told me too. (in the '79) I never had it repaired, being in CA and all.

I read that you can try just changing the amplifyer and see if that fixes it.

Is that change a big job or a plug-n-play?
Is it a bad idea that I read?
Thanks!

amplifier is plug n play so is the servo. reman all aluminum body servo with lifetime warranty is $400 and worth it if you live in the colder parts of the country and want to keep your car. If you spend the $20 for the FSM it has some pretty easy to follow instruction on how to test the system with some common tools.

Where to get the FSM for the 116.120?
I've never found one.
Thanks!

www.w116.org has the FSM available for free.

here: http://handbook.w116.org/matrix6.htm

If you have the 722.120 transmission that you are supposed to have ( or any 722.1xx four bolt pan), you HAVE a reverse band adjustment. Not sure this will fix your problem, but don't let anyone touch your transmission until he/she finds it, adjusts it and confirms that your band is kaput. The link I provided earlier has a good shot of what to look for. It's on the passenger's side, just behind the bellhousing. It is above (and hidden by ) a protruding servo-type thing ( I think it may be the kickdown)that intersects the case above the oil pan at a diagonal.

If you are not concerned about A/C in summer, you can find inventive ways to bypass the servo with a simple valve to provide heat. Yes, the amplifier looks to be easy to replace, but buried behind the glovebox. The servo probably isn't too hard either, just a lot of connections to keep straight.

Rick

if you feel like spending $600 or so, get the unwired digital replacement for the servo and amp. a few members here have had good results and considering the price for a rebuilt servo, might as well go modern.

Thanks Rick.
I'll get the car back tomorrow and find a place to put it up and
take a look under. I'm pretty darn sure the tranny is original to
this car.
Funny, I trust you all more than I trust a MB mech that's been
'doin' this 47 years, missy'.

I'm loath to bypass. I know many do, my DHs car is bypassed.
But all he gets is defrost and has to open the sunroof to let
some of the hot air out or his head will boil. And yet his feet
freeze. Plus I think it's just the first step in making my mint
condition beauty into a beater later.

The shop is going to check out the amp and see if it's pushing
power. If it is and the servo isn't working, then I guess we know
it's the servo right? I'll go and get a new amp and servo.
It seems pretty easy to install both, I did the bypass on DHs
car so doing the bottom part should be easy for me. I figure I'll
just unplug one wire set, plug into the new, and on until all that is
left is to bolt it on the firewall? Or is it easier to unplug, label and
then replug after the servo is installed?

Thanks guys (and gals). . .

Contact George Murphy, he can send you a procedure for testing the servo.

and where do you find the aluminum bodied rebuilt servo for $400????

why waste the time with the servo ($400) and possible replacement of the amp (to the tune of $200+) when you can go a little simpler and a bit more modern with the unwired solution sold by Phil and Roy

http://catalog.peachparts.com/item.wws?qty=1&mfr=UNW&sku=ACC2G04

if I ever get around to finishing my 116 SD I'll certainly get the unwired solution rather than screwing around with the quirky chrysler servo.

As it turns out, the amp needed replaced, servo now works and I have heat.