HELP, still no reverse after adjustment and oil bath stevebfl, M.B. Doc
 

stevebfl if your out there. I need to know how to adjust the reverse band on my transmission? It was recently installed and shifts fine now but takes 3-5 seconds to fully engage reverse. Also, on adjusting the modulator pressure, is it clockwise or CCW for softer shifts? Thanks for your help

jmdunn

Hey guys, I really need some help here. M.B. doc gave me the adjustment procedure on the reverse band and the modulator. I did that, now I have no reverse at all. Did I not tighten enough on the adjustment bolt. Do I need to look for other problems? I just installed this transmission and it is under warranty but I'll have to pull it again to exchange it . Is there any other thing that may be fixable to solve this with the transmission still in the car? I'm at a loss. HELP!!!!!

Also, I removed the reverseadjustment bolt from the transmisison and replaced it with the bolt from my old tranny which was in better shape(the new tranny's bolt had a bur on the end of the bolt). Did I mess up when I remove this?

thank you,
jmdunn :confused:

Possibly you did!! The adjustment bolt holds a guide pin that MUST align into the band. Possibly when you removed the bolt the pin fell out. You didn't tell me that you were replacing the bolt OR I would have warned you of that possibility.
ALSO on the other side of the band there is another of these guide pins & it too could have fallen out.

Ya, the pin fell out. Its not too big a deal, although you will have to remove the valve body. The pin will probably be sitting on the valve body.

Thanks a lot SteveBfl and MB doc. I'll check it out. You guy are the greatest.

still no reverse
 

I'm really lost now. I took the valve body out and found both adjustment pins where they should be. The band seemed to adjust fine when observed while adjusting with the valve body out. I put it all back together and still no reverse to speak of other than a weak slipping at around 2000 rpms. The company that sold the xmsn to me told me to take it to the shop. What things should I tell them to look for now to keep them honest? If they can fix it w/o taking the xmsn out of the car the company should pay for the parts and labor. If not I'm stuck pulling it and shipping it back for an exchange. Servo piston? Valve body problem?
HELP!!!!
Thanks a lot,
jmdunn

Before I wrote to check the pin I verified its existance with my main trans tech. He said to be sure I advised air pressure checking the servo while the valve body is out. I didn't because it requires air pressure and knowing where to put it.

There is a good chance that the problem all along was the servo piston seal or the piston itself. I have seen many broken by hi modulator settings.

Does anyone know where to get the seal or piston parts for this? Next, how hard is it to replace myself if I can't find a tech to do the job and how do I do it? Is there a way to verify it's the seal without the air pressure technique by removing the piston? I'm a little scared of local mechanics messing with it. Also the modulator setting, when we first installed the XMSN it shifted a bit hard. I adjusted the modulator clockwise 3/4 turn.

thanks again,
jmdunn

I see that this thread is 8 years old, but are any of you still out there?

I need reverse band adjustment instructions.

1977 450sl, 90,000 miles.

Previous to the incedent, it would take 3 -4 seconds for reverse to engage when shift lever was moved to R.

Driving long distance, stopped to fill up with gas. Resart car and no reverse. Just like it is in neutral. No grinding noises, breaking noises, smoke, etc. Just stopped working. With engine stopped and tranny in reverse, I can push the car as if in neutral.

Any tips/instructions are appreciated. Local tranny shops say repair =$2000. Want to charge almost $900 just to diagnose the problem.

350sl no reverse
 

Hi Mark,

Wondering if you ever resolved that issue you were having with your 450SL transmission?

I have the same problem:

-1976 350SL
-slow going into reverse for months now, and a couple of days ago nothing happened when put it in reverse (acts like neutral). If I rev very hard, it gets a little traction and will move.

Research so far suggests;

a)insufficient pressure to operate the reverse value, so blocked lines, low fluid or bad fluid.

or

b)reverse band adjustment required.

Local gearbox centre say that it is the lining on the reverse clutch, that it detaches over time, €900-€1500 rebuild needed. I am uncertain of this because I can't imagine an unlined clutch suddenly gripping at high rev, but then what do I know.

Did you have any success? any thoughts appreciated.

Somewhat an easy job.
The adjustment bolt is just above the kickdown solenoid on the passenger side of the trans.

The bolt needs to be "snugged down" then backed off 1 3/4 turns. Then tighten the jam nut.

1976 350SL, no reverse, reverse band adjustment
 

Solved!

1976 350SL, was getting slow to go into reverse and, starting recently, would only go into reverse when cold.

Per discussion, I looked for the reverse band adjustment bolt.

It was not a 10mm bolt with 22mm locknut, but a single 19mm bolt. As it had no locknut I tightened it fully and sure enough reverse works fine now.

It was hard to get at so try to jack car as high as you can, and remove the solenoid switch for access.

phew!