need transmission advise FAST - PeachParts Mercedes-Benz Forum

carlover · #1 08-25-2006, 10:07 PM

I just bought an '86 560SL with 62K miles on it. The owner was in her 70's and never drove it much so I doubt if this problem ever came up during her ownership.
When I really "stand on it ", it jumps back into 1st gear which would be fine except it tries to go into 1st at 55-60 mph. It goes into second and then into first, and if I hold it on the floor, it won't come out of first. It starts "bucking" like it is going in and out of gear. The normal shift pattern is fine. It goes through the gears perfectly. This is only a kick down issue. If I let off the gas slightly, or if I don't mash it hard against the floor, it seems to be o.k., except doing that means I'm not getting full acceleration. I assume that the kick down is electrical, and if thats true, I hope someone can tell me how to adjust it properly. I can see an electrical plug in the side of the tranny, but don't know if that's the kick down or not. I didn't see any mechanical linkage (other than the shifter) so I need some help with what to adjust. NO, I don't slam it against the floor often, but want to be able to do so without causing any damage. Any advise/help will be greatly appreciated.
Thanks in advance
Tom

Monomer · #2 08-25-2006, 10:39 PM

check your "kick down" cable

and that their's no carpeting/matts covering the switch.

carlover · #3 08-26-2006, 07:31 AM

Are you referring to the electrical cable going into the side of the tranny, and if so, what do you check ? I don't see any mechanical cable.

Larry Delor · #4 08-26-2006, 08:42 AM

I think he means the switch under the accellerator pedal.

carlover · #5 08-26-2006, 09:42 AM

There isn't anything like carpet between the accelorator and the switch, but it seems to me like that would cause it to engage sooner,but wouldn't cause it to fail to shift out of 1st in when in wide open throttle. Am I missing something here ? This is my first Merdcedes and I'm new to the forum, so I'm open to any suggestions.

david s poole · #6 08-26-2006, 12:22 PM

if you look behind the air cleaner you will see the accel linkage.look a little lower and you will see a cable coming from the trans[right or pass side] normally routed under the exhaust crossover pipe and attatched to an arm on the accel linkage[push on ball] if you find this and then follow it you will see a straight adjustable rod that connects via a push on ball at each end. this rod has a 8mm bolt head holding the adjustment.by making this rod longer you will stop the trans from holding the gears too long and of course the reverse is true.

dkveuro · #7 08-26-2006, 12:24 PM

The 'bucking' is the rev' limiter cutting in.

.

carlover · #8 08-26-2006, 01:28 PM

David, are you talking about the flat adjustable piece that goes to the pivot device that the cable is attached to. Looks like it's about 8in. long, maybe 3/8in.wide, right on top-- silver in color, with one screw holding two sliding pieces of metal together ? If that's what you are talking about, mine can be shortened around 3/4in. Should it be adjusted as far as it will go the other (short) way? It is now adjusted as far as it will go in the other (long) direction. Won't that effect the normal shift pattern, or is that kick-down only ? I don't see any adjustment on the cable itself unless it's under that red accordion cover at the top, or am I just missing it ?
Tom

raymr · #9 08-26-2006, 03:05 PM

It will affect your shift pattern, but if you want to try changing it, mark the current position so you can set it back later. Also see what happens if you temporarily disconnect the kickdown switch.

carlover · #10 08-26-2006, 06:18 PM

Many thanks to all, especially David S Poole for his excellent description. I was wrong when I said that my adjustment was as far as it would go in the long direction. In fact it was just the opposite, and after a lot of trial and error, I have it close to where it should be. Although I found it to be a simple adjustment, I also found it to be quite sensitive. An eighth of an inch makes a difference. Thanks again to all for you efforts.
Tom

david s poole · #11 08-28-2006, 09:26 AM

well i'm glad that you found the adjustment rod.if it was as short as poss it certainly explains the strange shift behavior.do i gather it is now fixed? you know it didn't get to be that short by itself. good luck.

carlover · #12 08-28-2006, 10:46 AM

I suppose you could say it's fixed. I would prefer that it downshift into low at a little higher speed like 35mph, (now it's closer to 25mph) so as to get the benefit of the higher rpm range, and I guesss if I keep adjusting in very small increments, I might eventually get there, but for now it simply goes into second at that speed, which doesn't really give it much "kick", but I can live with it. Thanks again for all the help.
Tom