Over the weekend I replaced my engine mounts and shocks while replacing the oil cooler lines. It drove ok last night. On my way to work it started vibrating mostly in first gear. When I stop at a light, it stays smooth for a minute or so and then slowly starts to pick up a vibration. If I put it into neutral though, it stops. I don't see anything visibly loose or anything and the motor definitely is much smoother with the new mounts. Could it be related to the mounts if it stops shaking in neutral or does that sound like more of a transmission issue? I'm a little wary to drive it if it's got some grinding in the transmission or something. I don't know enough about these things to diagnose. Any tips are appreciated.

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"Gerwalt" 1984 - 300TD

When you put the transmission in neutral you take the drag load from the engine, the engine speeds up and at the same time becomes much smoother. You might possibly do a compression check when convenient to see that all is well. With low compression on one cylinder they will shake a little more at idle and still run pretty good. The five cylinder is a difficult engine to keep smooth at low engine speed. I don't think in anyway that the problem is connected to the transmission.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

It wasn't there before the work this weekend and scared me a little since it seemed to get more intense as I accelerate.

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"Gerwalt" 1984 - 300TD

Tranny mount? Maybe when the engine was jacked up, it made the failing (but not failed) mount fail.

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1989 300E 144K

How serious is that?

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"Gerwalt" 1984 - 300TD

About $20.00 for the part and easier to replace then the motor mount

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

I just drove it and I would describe it more of a thumping or knocking sound when in gear and sitting still and when the pedal is close to the floor in 1st. In 2nd and up it doesn't knock/thump unless I really jam the throttle and then it's barely noticeable. It's down low and maybe to the passenger side a tad from how it feels driving it.

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"Gerwalt" 1984 - 300TD

Just throwing this out there but are you absolutely sure its not the exhaust on the underbody making contact? Jacking up the engine to get mounts in could tweak the exhaust just enough for it to contact when in forward gear and not in N or R. Also the new mounts probably are sitting a tad higher. Id check the trans mount too.

I would give the entire drivetrain a once over. Possibly unrelated, but jacking the motor will often put extra stess where it normally wouldn't be. Check you tranny mount, front and rear flex disks, center carrier, etc.

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1989 300E 144K

I'll get it jacked up tonight and poke around. To be honest I don't really know what all to look for. I can probably get vstech to help me diagnose it, I know he would know what to check. Thanks for the tips everyone.

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"Gerwalt" 1984 - 300TD

Try to take it to his place this time.

More tools, spare parts, and fun driving your car..

yeah, we've discussed it, and I've pointed him in the direction to look. I'll be available later tomorrow to assist in the investigation. we're leaning towards the exhaust. It's amazing how much more info comes across verbally than typing.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

It was the engine mount bolts. I had forgotten to tighten the again after everything had time to settle. I did check the transmission mount and it was pretty gooey on the front for about a half inch deep. The backside is dry and firm. Replace?

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"Gerwalt" 1984 - 300TD

HA!
my first thought was correct!!!

I'm glad you found it. hammering sounds are usually related to the motor mounts hitting the frame, the exhaust makes an almost tinny sound in comparison!

YES.
That will continue to degrade and fail when you need it most..