: 98 SLS Trans/mounts Questions



El Dobro
03-06-04, 02:42 PM
Ok, I have a few questions on my 98 SLS. Here's whats happening. When I accelerate, I feel what could best be described as a sizzle coming through the gas pedal. When the gears change, it's gone, but comes back as the engine revs up.
Next, when I'm in stop and go or slow moving traffic, there's a thump when I take my foot of the gas and then put it back on. The slower I go, the more the thump. Even when I'm at speed, I can still feel it, just not as bad. It feels like the older drivetrains that have a bad dogbone on top of the engine.
Lastly, when I do a neutral to reverse or neutral to drive shift, there's a delay, then clunk/clunk.
I've tried the car in gear/foot on the gas to see how much the engine comes up to check the mounts, but it only comes about 1"-1 1/2". I'm pretty sure the mounts are hydraulic, so I checked around for leaks and didn't see any.
Any ideas out there?

BeelzeBob
03-07-04, 12:29 AM
Ok, I have a few questions on my 98 SLS. Here's whats happening. When I accelerate, I feel what could best be described as a sizzle coming through the gas pedal. When the gears change, it's gone, but comes back as the engine revs up.
Next, when I'm in stop and go or slow moving traffic, there's a thump when I take my foot of the gas and then put it back on. The slower I go, the more the thump. Even when I'm at speed, I can still feel it, just not as bad. It feels like the older drivetrains that have a bad dogbone on top of the engine.
Lastly, when I do a neutral to reverse or neutral to drive shift, there's a delay, then clunk/clunk.
I've tried the car in gear/foot on the gas to see how much the engine comes up to check the mounts, but it only comes about 1"-1 1/2". I'm pretty sure the mounts are hydraulic, so I checked around for leaks and didn't see any.
Any ideas out there?

Did you do the brake torque maneuver in drive AND reverse to gauge the movement of the powertrain and any possible grounding or noise? The engine rocks one way in drive and the other way in reverse so if there is a weak mount it may only show up in one direction.

You really need to get the car on a hoist and into the air when doing this so that someone can watch/inspect the mounts from underneath the car.

El Dobro
03-07-04, 07:10 PM
Hi again,Bob. Yep, I tried it in drive and reverse and it moves even less in reverse. The clunking seems to be coming from the trans. Like I said before, when you shift, there's a delay then clunk/CLUNK and that happens in drive and reverse. When the drivetrain is totally warmed up, it's even louder. My Northstar Allante does none of this. The trans in that is as quiet as a church mouse.
I'm compiling a list of things for the dealer to fix and I'm trying to point them in the right direction.