Should I save it or ditch it? - PeachParts Mercedes-Benz Forum

Diseasel300 · #1 06-20-2017, 02:27 PM

Change the tranny oil and filter before moving forward. You'd be surprised how much that can change the shifting characteristics. My SDL had old fluid that looked and smelled fine, but would shift so hard it would bark the tires through 3rd. Every shift, especially 1-2 felt like someone ran into the back of the car. Changed the fluid and filter and it was immediately better, after driving it for a few hundred miles it's surprisingly smooth.

If you have a bunch of sludge and crap in the fluid and the modulator is clogged up with varnish and debris, your cold shifting will be firm. If you try to overcome that by messing with the modulator, you're going to be slipping and flaring like crazy once the fluid heats up.

One thing is for certain: If you keep on driving it like it is now, you WILL need a transmission. From the sound of it, you need to service the one you have and set it up PROPERLY instead of just fiddling with things arbitrarily.

danielevioli · #2 06-20-2017, 03:05 PM

Quote:

Originally Posted by Diseasel300

Change the tranny oil and filter before moving forward. You'd be surprised how much that can change the shifting characteristics. My SDL had old fluid that looked and smelled fine, but would shift so hard it would bark the tires through 3rd. Every shift, especially 1-2 felt like someone ran into the back of the car. Changed the fluid and filter and it was immediately better, after driving it for a few hundred miles it's surprisingly smooth.

If you have a bunch of sludge and crap in the fluid and the modulator is clogged up with varnish and debris, your cold shifting will be firm. If you try to overcome that by messing with the modulator, you're going to be slipping and flaring like crazy once the fluid heats up.

One thing is for certain: If you keep on driving it like it is now, you WILL need a transmission. From the sound of it, you need to service the one you have and set it up PROPERLY instead of just fiddling with things arbitrarily.

Ok... so a little more back story. The tranmission fluid is black and smells burnt after a ride.

I didn't so much fiddle arbitrarily... when I first got it it would shift very late, but the quality of the shift was all right. I bypassed all the vacuum control and adjusted the VCV to spec. It would run well until hot.. then started slipping. Then I tried to increase modulator pressure by turning it clockwise, a little better, but then over time got worst. Fluid is black and smells burnt. As mentioned, I was going to swap the transmission fluid and filter. Instead, I put lucas in, and the day after I put the lucas in it got A LOT worst. Since I replaced a quart of fluid with lucas it started slipping/flaring REALLY BAD, became dangerous to drive.

Since it's going to cost about $100 to swap the fluid and filter (and I've heard that fluid change can cause unwanted damage on old transmission) I'm thinking it might be a waste of money, seeing how badly it's slipping...

I've also had a hard time finding the proper filter.. this tranny has no dedicated drain plug... the plug goes to a banjo bolt and hose to somewhere.

mach4 · #3 06-20-2017, 03:11 PM

Quote:

Originally Posted by danielevioli

...I've also had a hard time finding the proper filter.. this tranny has no dedicated drain plug... the plug goes to a banjo bolt and hose to somewhere.

Huh? Pictures and tracing the hose would help a lot. Where does it go and what's on the other end?

Diseasel300 · #4 06-20-2017, 04:47 PM

Quote:

Originally Posted by danielevioli

Ok... so a little more back story. The tranmission fluid is black and smells burnt after a ride.

I didn't so much fiddle arbitrarily... when I first got it it would shift very late, but the quality of the shift was all right. I bypassed all the vacuum control and adjusted the VCV to spec. It would run well until hot.. then started slipping. Then I tried to increase modulator pressure by turning it clockwise, a little better, but then over time got worst. Fluid is black and smells burnt. As mentioned, I was going to swap the transmission fluid and filter. Instead, I put lucas in, and the day after I put the lucas in it got A LOT worst. Since I replaced a quart of fluid with lucas it started slipping/flaring REALLY BAD, became dangerous to drive.

Since it's going to cost about $100 to swap the fluid and filter (and I've heard that fluid change can cause unwanted damage on old transmission) I'm thinking it might be a waste of money, seeing how badly it's slipping...

I've also had a hard time finding the proper filter.. this tranny has no dedicated drain plug... the plug goes to a banjo bolt and hose to somewhere.

Find the year of the car and the model of the transmission (stamped on the side). That will get you pretty far. The pan has to come off to change the filter anyway, so just pull it and change the thing. You will have a 722.1 or a 722.3 transmission depending on the year and whether it is original to your car.

Black fluid is bad fluid. Needs to go and may be your primary issue. Considering you've been fooling with vacuum and modulator settings, all bets are off there. Get to a clean slate and set it up from scratch. You'll know if you have problems or not at that point.

Blindly going out and buying a transmission is foolish. Especially for a used one of unknown quality. It may be even worse than the one you have.

Bottom line: If you're so cheap that you can't afford an oil and filter change for the car, you don't need to be owning it. Sorry to sound so crass, but you can't wave a magic wand at it and fix it. You'll be putting that money into a new one anyway for the very same service, so get it out of the way first and find out if you need to drop money on a transmission or if the one you have is serviceable and you just screwed it up by messing with things you shouldn't be messing with.