: Tranny clunk in 98 sls



509Rider
03-25-04, 12:53 AM
First off were I park my car at night is on an incline, when I shift to reverse it clunks really hard, I hate it, but now when I drive down the street let off gas and then press the gas again it feels like theres some play like something is loose, do you think its the motor mount, drive axels?

BeelzeBob
03-25-04, 01:47 PM
Have you ever heard of a device called a "parking brake"....LOL That is what it is there for. Especially when parking on an incline. When you come to a stop, hold the brake firmly, put the trans in park and apply the parking brake BEFORE releasing the service brakes so the parking brake takes the load and not the parking pawl in the trans. The parking pawl in the trans is designed to handle the load...but...it makes that annoying clunk when pulling it out of park with a lot of load on it. Use the parking brake to eliminate this phenomenon. If your parking brake will not hold the car like this, then get it adjusted.... When you fix to drive away, put the car into gear BEFORE releasing the parking brake so that the parking pawl is not loaded.


As for the clunk during driving it may be an engine mount.... At a stop, open the hood and put the car in drive. Watch the engine/trans under the hood while you crowd the gas pedal while holding the brake firmly....i.e.....powerbrake the heck out of the engine while watching the engine under the hood and listening for the characteristic thump you describe. Do the same in reverse. Powerbraking like this will load the engine/trans mounts and if one is failed you should see some abrupt motion in the engine movement under load and/or hear the noise you describe.

509Rider
03-25-04, 11:19 PM
Ya thats my fault for not using the parking brake I thought it was like my fleetwood and let the brake off when you put it in gear, I tried the brake method and put it in drive and then reverse the engine did rock , but no clunking noise, how much should the engine move?

BeelzeBob
03-26-04, 10:40 AM
Ya thats my fault for not using the parking brake I thought it was like my fleetwood and let the brake off when you put it in gear, I tried the brake method and put it in drive and then reverse the engine did rock , but no clunking noise, how much should the engine move?

It will move about an inch or so each way when it rocks on the mounts. The amount isn't as important as listening for the clunck you describe and/or sudden jerky movements as you load it that would indicate a broken mount. If the rubber isolators in the mount fail the mount will still hold up the engine and restrain it but the movement will not be as controlled when it rocks under load.