using sealer additive for leaking auto trans
 

1988 300E w/155K miles - trans works perfectly - no measurable fluid loss - slight leak and drip after sitting - coming from front pump seal area - appears to be candidate for additive leak sealer - any recommendations as to brand - or cautions will be appreciated

If you are planning on keeping the car, don't use a sealer. If you are selling it, go ahead. The sealer swells everything up inside, not just the pump seal. I have experience with this.

I used Trans-X, after about 9 months, it started leaking anyway. I was advised to change fluid several times to get as much out as possible.

My advise is, if the tranny shifts fine and isn't leaking badly yet, start saving up the $800-$900 to have it re-sealed. If it's not performing well, drive it until it breaks or until you get $2500 together for a new tranny.

One last bit of advise. I'm not one to recomend the dealer for repairs. However, Mercedes trannys are a different animal. Your local Aamco shop really isn't the place to have this done.

I paid $900 to have the dealer seal mine and two and a half years later, no leaks. Oh yeh, have the rear seal done too.

We all have different levels of tolerance for these sort of drip problems. My tolerance is fairly high because I have a drip pan on the floor of the garage to catch the drippings - and I have measurable transmission fluid loss, even when just parked. It probably needs to have a pint every 3000 miles added. (That's the '82 300D.)

I have to suggest not using any kind of transmission additive that is supposed to "repair" the transmission. I had a pickup truck with a failing, leaking transmission and tried some of the stuff. It caused the transmission to completely fail within 500 miles.

If I had your car, I'd get the drip pan on the floor. If parked in the driveway, I'm not sure what is reasonable to do for leaks. But I'd just drive the car.

Ken300D
'82
'87

My local ******** owner recommends Wynn's Seal Conditioner. It is not a repair fluid. He says that with the high operating temperatures, seals become hard and conditioner does no harm to the internals. I've had success with it, but I think we're all in agreement that a persistent or bad leak needs a new seal.

Thank you all