Hello all,

I have a 1988 260E with the 2.6 engine.

Running around town for a couple of years now, the tranny would once in a while not want to go into fourth gear. But it would always fix itself.

When I go on a long trip (say 40 minute 70 to 80 mph) on warm days This would happen for sure. The other day it happened and I noticed ATF had come back out the dipstick tube. Also during this trip, the coolant tank dropped low enough to trip the low coolant sensor.

The next after it cooled down, I found the ATF to be about 1/2 quart low. I replaced the fluid and she drives fine. I have not been on another long drive tho.

It did not feel like it was slipping at any point.

The radiator is around a year old.

Should I add a transmission cooler? Or is a rebuild around the corner?

Thanks
Joe

Your radiator already has a transmission cooler built in. Are you checking the transmission fluid level with the car parked on flat ground, running, in park and fully warmed up to operating temperature?

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As mentioned above, your radiator has a transmission cooler built into it. Because of this, you should be taking the low coolant/overflowing ATF situation VERY SERIOUSLY. If the transmission cooler has failed and allowed coolant into the transmission, you will very quickly ruin it! ATF won't be running out the dipstick tube unless something else has entered the system to displace it or the transmission was grossly overfilled to begin with (and even then it should bleed out the vent before it comes out the tube).

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Thank you.

Yes the fluid is checked with vehicle warmed up, on flat ground and in park.

If the water was getting into the transmission lines, would it not register overfull instead low?

When ever you say " ATF had come back out the dipstick tube. " Did fluid end up on the ground or was the level just higher on the dip stick?

"When ever you say " ATF had come back out the dipstick tube. " Did fluid end up on the ground or was the level just higher on the dip stick?"

It had sprayed onto the firewall, valve cover and breather cover.

The vent on top of the transmission is blocked. Fix that issue first.

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Yep, vent is the first step. If the trans has an internal pressure leak, fluid will become aerated , expand then be pushed out the dip stick tube. Next time you check the fluid, look to see if there are bubbles on the stick.