Car rolls in Park

[JWJ]

Recently, my '83 300D has started rolling when in Park. This happens even on small inclines.

I would stop, put the car in Park, shutoff, remove my foot from the brake pedal and the car starts to roll backwards. When rolling backwards I hear a clicking sound coming from underneath the car.

Pushing the brake pedal again and applying the emergency brake (left foot) stops the car.

What would cause this?

JWJ

[JamesDean]

1...perhaps the parking prowl inside the transmission is busted.
when I shift into park my car will rock a little forward/backward until a clank is heard. that is the parking prowl catching.


2...perhaps when u shift into park, the shifter is not putting the trans into park fully...that would be a problem in ur linkage underneath in the tranny tunnel.

just a guess thou...

[sodapop6620]

I would look at the parking prowl. I had a van that did this and the locking key had been sheared off . This was caused by putting the van in park before the vehicle was completely stopped.

[TwitchKitty]

I second the idea to check the linkage. The bushings in your shifter are probably worn out or missing, and not shifting the trans into park. If the shifter is ok, dig deeper.

[engatwork]

My 300D did this until after I replaced the bushings in the shifter mechanism (not the bushing underneath the car).

[Obnoxio]

Mine did the same thing, plus would hold the 2-3 shift for a rediculous amount of time. Turned out to be the shifter bushing, which was fixed for 50.00 total at the local indy benz guy. Car shifts waaay better, probably because it had no idea what gear it was in due to the shift selector being out of whack. On these cars, it seems to be little simple things that wear out.
-TB

[JamesDean]

if your replacing the shifter bushings under the car and when you finish your car doesnt start. (this actually happen to me) its more than likely that your Neutral Safety Switch kicked the bucket. All we did was tap mine and it died. it was 24 years old also...

Just an FYI, in case....


Kris

[pawoSD]

I'd agree with the shifter bushings, my car has a tight shifter, and the park locking mechanism works great (never chinks or skips) but our '83 has a slightly loose feeling shifter, and from time to time it will not catch the prowler and hold the car, sometimes it slips out of drive too....we'll probably replace the bushings sometime soon to remedy that problem....

[gdemoss01]

Originally Posted by TwitchKitty

I second the idea to check the linkage. The bushings in your shifter are probably worn out or missing, and not shifting the trans into park. If the shifter is ok, dig deeper.

My 300SD starting doing the same thing, crawled underneath and no shift bushings left. Ozarks engineered some from rubber-like fuel line and that worked fine and solved problem.

[SD Blue]

Here is a website that has a little tool to install the new shifter bushings with: www.**************.com

It definitely would be a good idea to use the parking brake!

[Nate]

guys, why does a 16 year old have to say this?

Its a transmission, not a kickstand... It's not ment to hold the vehicle on.

Use the parking brake frequently, and the added bonus is that it wont seise up from rusting...

Nothing makes me chringe more then the sound of somebody shifting out of park, when they didnt use the parking brake.

Notice how it's hard to pull out of gear? Thats harsh metal to metal wear on the parking paw.

parking brake, not emergency brake


~Nate

[Mustang_man298]

I fully agree with the linkage or pawl thoughts. One other thing, not likely but possible, is that the pawl and sprocket have become worn at the engaging dogs, and are "ramping" the pawl out of lock. I also agree with using the park brake. I see a lot of folks that don't, that gear was only meant as a backup safety for anemic park brakes, or backward rolling (park brakes don't work well in reverse by nature of design) Using the park gear as a full brake, shifting before completely stopped, or continuing to drive with a slipping park gear or misadjusted linkage will wear the park gear badly and it will begin hopping teeth. I have replaced many a worn one from this during rebuilds. (and "hard" parts are not cheap)

[TwitchKitty]

Replacing all shifter bushings on W126 - p.1

Links to a write-up on replacing shifter bushings in a 126.

http://www.peachparts.com/shopforum/diesel-discussion/96048-broken-neutral-safety-switch-replacing-shifter-bushings.html#post646647

Links to a write-up on replacing shifter bushings in a 123.

[gatorblue92]

when my shifter bushings went they also kept the car from starting in P so i just stored the car in N and started it there as well and always set the parking brake (which i do anyway) and didnt have any problems

[pawoSD]

My parking brake recently died (was working perfect before something broke, haven't had time to check what it is) and so I've been having to use the tranny as my parking brake on hills, its been working just fine, and I don't know about "wear" on the parking prowl, that thing sounds like a 5lb metal arm disengaging when you release it on a hill, keep the door open and listen to it, it sounds massive, not like new cars where it "chunks" and sounds like your sanding it away. Our van's steeringwheel actually shudders if you release it from park on a hill without having used the parking brake... Anywho, I am betting that at the very least, the prowl wouldn't wear out between tranny rebuilds at the least....I'd place a bet 95+ % of problems with this function on these cars is from loose bushings or a linkage problem.