1987 W124 not starting in PARK, but starts in N - PeachParts Mercedes-Benz Forum

johnscars · #1 02-21-2014, 08:06 PM

87 300TD recently ceased starting while in PARK when engine is cold - like it is not connecting to electric power - but it starts in NEUTRAL. And after the car warms up it sometimes "connects" to power and will start in PARK. Anyone experience this and know what can cause this?

I just filled my tank and the gas station mechanic said it happened to his car recently - it was his NEUTRAL SAFETY SWITCH. He said it will eventually not start in NEUTRAL - so replace it. Does anyone know where it is on a W124 and/or how to test it?

Thanks,
John

87 300TD 330K

ridgerunner · #2 02-21-2014, 09:34 PM

Definitely the NSS. Located on the left side of tranny. Your shift lever rod connects to the shaft/lever that's in the center of your NSS. Could of possibly came unlocked; could be corrosion in the connection. Not hard to replace if you do your own maintenance.

vstech · #3 02-21-2014, 09:58 PM

the MOST likely issue with this problem is the shifter linkage bushings are worn or gone...

6.00 worth of parts, relatively difficult to change... two will likely be needed.

one on the arm under the shifter itself, and one on the arm on the transmission.

vstech · #4 02-21-2014, 10:02 PM

1987 Mercedes-Benz 300D Base Sedan - Shift Linkage - Page 1

changing them is easiest with the official tool, but can be done with a flat piece of metal, a pair of channel lock, slip jaw pliers, and a 17mm or so socket...

johnscars · #5 02-22-2014, 02:43 PM

So it may be more a problem with corrosion and/or worn-out shifter linkage bushings - and maybe not a bad Neutral Safety Switch? I take it you guys have addressed this (changed these bushings) a number of times. Did the cars also need to replace the NSS?

If the NSS is a wear item, then I ought to be ready to replace it when addressing the linkage, but if you think this is probably more a bushings/corrosion problem - I'm good with that.

While the car is up - might be a great time to address the hard 1st-2nd shift. This tranny has a replace K1-kit, and the side-mounted Vacuum Modulator's dial is turned all the way to the left. I was told the solution to the hard shift is to remove the plastic dial and reposition it so that it has more ability to turn counterclock.

Does anyone know if K1-kits wear out and need to be replaced? this one has at least 60k on it, maybe a lot more. And of course it's time to change the tranny fluid and filter.

JamesDean · #6 02-22-2014, 03:03 PM

Quote:

Originally Posted by johnscars

So it may be more a problem with corrosion and/or worn-out shifter linkage bushings - and maybe not a bad Neutral Safety Switch? I take it you guys have addressed this (changed these bushings) a number of times. Did the cars also need to replace the NSS?

If the NSS is a wear item, then I ought to be ready to replace it when addressing the linkage, but if you think this is probably more a bushings/corrosion problem - I'm good with that.

While the car is up - might be a great time to address the hard 1st-2nd shift. This tranny has a replace K1-kit, and the side-mounted Vacuum Modulator's dial is turned all the way to the left. I was told the solution to the hard shift is to remove the plastic dial and reposition it so that it has more ability to turn counterclock.

Does anyone know if K1-kits wear out and need to be replaced? this one has at least 60k on it, maybe a lot more. And of course it's time to change the tranny fluid and filter.

Do you feel slop in the shifter when you move it up/down or side to side?

Here is a link to the neutral safety switch:
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

As far as your shifts are concerned, this kit might benefit you:
Superior Transmission - Superior K722A-D

It comes with all kinds of different items that can be installed to try to fix a myriad of different issues. The have different springs in there that can help the 1-2 shift.

johnscars · #7 02-22-2014, 06:25 PM

Linkage doesn't feel sloppy at the shifter - in fact it feels really good - self centereing and lively, snappy might be the word.... but with what I'm learning, I should climb under and take a look, shake things up, spray a little WD-40, check out the 3 bolts on the NSS for access, and check out the shifter linkage bushings.

gatorblue92 · #8 02-22-2014, 07:44 PM

Seeing as the car starts normally when its warm I would think its the switch however I would also be inclined to replace the bushings "while you are there."

johnscars · #9 02-22-2014, 09:19 PM

Yeah, I just started it cold in PARK. But after turning it off for 10 mins it would not start in P, no matter how much I moved the shifter. But it started right up in N. So rather than jacking up and climbing under it, I decided to recycle my waste oil tub - so when I jacked it up I can change the oil, too... manana.

The erratic P starting is the NSS telling me loud and clear - change me!

John, if you check back - do you recommend 2 sets of bushings because it needs 2, or because I'll probably bugger one - especially if I'm using the channel locks, metal plate, and 17mm socket. thanks

These are the part number I've found:
linkage bushing(s) 115 992 03 10
NSS part # 000 545 49 06

Zulfiqar · #10 02-23-2014, 04:32 PM

my NSS problem on the E300D was very similar. The culprit was someone had hacked a rudimentary security system and butchered the wiring that goes to to it. This wiring connector is above the black plastic knee plate on the dashboard.

It also was being fed water from the A/C drain pipe on that side. Nice corrossion going on too.

Cleaned it out, soldered the connectors again, sealed up the wiring and never had a problem after that.

I did buy an NSS for it and ended up stashing it.