Transmission clunks in Park

[TopherS]

I've noticed in the last week or so that whenever I put the car in Park, that if the car rolls forward toward the stop, that it "clunks" as it gets to the stop. Whenever I park on a slope, I use the parking brake, but not on level (or relatively level) ground. For instance, at work, I rent a space and the car sometimes will roll just slightly when I park...othertimes, it won't. If it does, it will "clunk" as it touches the stop. I just had the oil changed the other day and the transmission fluid was checked then and I was told that it was full, plus it was bright pink and no smells to it at all.

I think, to be safe, I'm going to have to start using the parking brake whenever I park, regardless of the slope...or lack thereof.

But is this an indication that my transmission is starting to go bad?

[HotZ28]

It's possible that you have a bad motor mount, or even internal damage to the paul lever, but I would always use the E-brake when parked on a slope, rather than relying on the internal park lever (paul) inside the trans. Follow the procedure below.

1) Stop vehicle;
2) Firmly set Parking Brake;
3) Put transmission in Neutral;
4) Let off foot brakes (slowly, to make sure Parking Brake is holding); then
5) Put transmission into park.

If you follow this procedure, there is no strain on the transmission whatsoever.

[TopherS]

I was thinking of the parking pawl, too, but I've never seen one go bad. I always use my Parking Brake on a slope, but I'll start using it always now, just to be sure my car stays where I park it.

I've had a motor mount go bad about 3 years ago...my mechanic found it while working on something else. Not a stretch to think another one has gone bad. How many are there on this car?

[HotZ28]

I have broken several "Anchor" mounts within a year. Did your mechanic use a genuine GM mount, or Anchor Brand? You should inspect all 4 or 5 mounts for damage.

[TopherS]

Thanks for the reply. I called my mechanic and his office manager said that he would have used "DEA" or something like that, but a hydraulic mount. His opinion is the same as yours, that another mount may have gone. I have an appt on Friday and he'll have all of the mounts looked at...and at no-cost to me

Thanks again.

[HotZ28]

Three years is probably about the limit for an after-market replacement. Shown below is the typical mount that fails (Left front trans mount)

Anchor Mount Features & Benefits

1. Both natural & SBR (Styrene Butadiene) rubber provide good abrasion resistance and aging stability to ensure maximum life & performance
2. All Rubber material is manufactured to specific Durometer (hardness) measurements based on the vehicle's application requirements
3. All fasteners are made of hardened steel with heat treated Grade #5 bolts
4. A special Chemlock® bonding agent is used to ensure a superior rubber-to-metal bond
5. Hydraulic Mounts (applicable where OE) are designed for most front wheel drive vehicles, because of the transverse drive train mounting

[TopherS]

So, if the mechanic tells me tomorrow that I have a mount that's bad, should I go buy a GM replacement and have them install that one, rather than the aftermarket type they ordinarily use? Would there be a significant difference in cost?

[HotZ28]

If you have the money to buy an original GM mount, that would be my recommendation. They do cost more, but also last longer. Even if you can get a lifetime warranty on the after market brand, that does not cover labor to install, which could cost more than the mount.