Trans or Engine? 190E 2.6
 

I have a 1991 190E 2.6 175K It sat for a year or so and I just revived it. I took it home did cap, rotor, wires, fresh oil and filter etc. It fired right up and ran great. (I have owned it for over 12 years but my son has used it for the last 6) On my test drive I was sitting at a stop light and heard the engine "Tapping" I pulled over and the "tapping" was gone when I opened the hood. It seems it is smooth and quiet in Park or Neutral but starts to sing when in gear. Any time I am stopped it "taps" and if I shift into N or P stops regardless of engine temp. I checked the trans and it took a quart to bring it up to the proper level. I have noticed it does not shift perfectly until it has run for a few minutes.

I have some deteriorated vacuum lines but everything else looks good and at 30MPH and above still runs outstandingly well and is getting 24.5-26 MPG combination city highway (I drive it 120 miles per day) I was thinking maybe a transmission/torque converter issue. My son had a heater core failure and overheated it but it does not overheat or use any coolant at this time.

I thought I would solicit some ideas from the group before I do a trans fluid & filter change so I don't feel like an idiot if it doesn't help and someone here had seen the problem before. I have searched and searched and cant find any posts that help me.

ANY ideas appreciated.

Thanks

check your vac lines,any auto parts will have some,do change filter,and trans fluid.

Howdy Neighbor. I live in Cosby next to Gatlinburg. THANKS! Ordered a filter this morning. So I guess you agree that it may be trans related?

Charlie

Tap or buzz? I've had various transmissions make a buzzing noise from a transmission valve body valve. Past that, noises are difficult when one can't hear them in person. ( and even a recording can be difficult. )

It is an ENGINE valve tap. Can clearly hear it. If my wife sits in the car and shifts from P to N it starts and stops with the shift.

Thanks

GM trans will make a sucking noise when filter is dirty.When you get could vac lines suck on line going to trans,to see if modulator is bad.fluid will come out if bbad.

I don't know if your engine has hyd. lifters.They can free up over time,or get a can of valve medic,and follow instructions.

Will do. I am heading to town for the filter and fluid. Will check before I go.

THANKS!

Yes. The M103 has hydraulic lifters. I actually changed them out less than 20K ago. She idles and revs in park as quiet as a church-mouse.

Thanks

I love to have a benz like yours

Then why are you asking , in the title, if the trans will cause this issue? The only thing a trans will do is pull the idle down a bit.

Because I was not certain if the trans, especially a bound up torque converter could cause it.

Thanks

cj:

The possibility exists that one or more of the flexplate-to-torque convertor bolts is loose. In neutral the TC is free to rattle, while in gear, the load holds the bolts against the plate.

Sometimes a bad bushing in the belt tensioner shock can cause a ticking very close to the sound of a valve.
Easy to check. Pry against the bushing with a screw driver & see if sound disappears.

Also a loose spark plug can do it. Not sure how I manage to not tighten one down but it stayed in place for months before I figure it out.