Author Topic: Automatic Transmission Additives  (Read 269 times)

gcw206

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Automatic Transmission Additives
« on: January 19, 2020, 15:43:33 »
I have just bought a 1969 280SE W111 Coupe that, according to the written service records, had only been driven about 1800 miles in 11 years.  After the car has been driven, the automatic transmission will leak for a bit from the frontal area, and then stop.  I was told that the main seal has probably dried out due to lack of use, and may need to be replaced.  I have heard that the additive Trans-X will swell the old seals, and stop the leak.  Is this correct?  Is there ANY downside to drawing off a quart of transmission fluid, and then replacing it with one quart  of Trans-X Additive?  Or should the transmission be removed, and the seals replaced?

wayne R

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Re: Automatic Transmission Additives
« Reply #1 on: February 11, 2020, 15:49:39 »
If it was my car i would not ad any additives to the transmission, but i would change
the fluid  to to a specified  brand or ATF dex 111,make sure it is correct level,engine at
operating temp, in park, level ground, and give your car a run every week for at least 10 miles,
for about over 1 month period, you might find it gets better.
Place a piece of cardboard under your car in that period ,see if it improves.
Also a small tranny leak is not a big problem.
1965  230SL  Auto, Ex CA.

wwheeler

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Re: Automatic Transmission Additives
« Reply #2 on: February 11, 2020, 18:13:33 »
I wouldn't add any thing either. Keep in mind that Mercedes recommends that you use a piece of leather to wipe the dipstick when checking the level. They don't want the lint from a rag to spoil the transmission. Seems a bit over the top to me, but they seem concerned about what you put in it.

With use, it is possible the seal will swell some to create a seal. Dexron is a pretty aggressive fluid and will cause rubber to swell even when new. So it is possible that having fluid swishing around the seal may invigorate it.
Wallace Wheeler
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

Benz Dr.

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Re: Automatic Transmission Additives
« Reply #3 on: February 11, 2020, 19:50:34 »
I've used Lucas Transmission Fix a few times. Since it was used on a trans that already didn't work I wasn't too worried about it. Didn't stop any leaks ( not that I expected it to ) but it did shift better.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

gcw206

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Re: Automatic Transmission Additives
« Reply #4 on: February 12, 2020, 22:09:54 »
Ok, it seems a majority here.  I decided to just live with the leak; the more I look at it, the less offensive it looks.
Thank you,
Galen