Hey guys,

First post here! I wish it was all good news, but no dice.

I bought a 1990 240DL w/ approximately 250k on it. The transmission was full of fluid when I bought the car, and I drove it somewhere in the neighborhood of 300 miles or so. I started noticing this little jerk in the transmission, slipping if you will. Not hard shifting, it engages fine in every gear. I checked the fluid last night and at running temperature, the dipstick was dry. This morning I checked it cold and it showed a little bit of ATF on the dipstick but not much. I took the car out, got it warm, and then checked it again. The dipstick was dry. I then added about three quarts of ATF (which put the dipstick over full) and drove some more. It still wanted to slip in first and second gear, but it took a little effort.

I put the OD bypass kit on it a few days ago, as the solenoid was bad, and am certain that I did it correctly. I even checked the car right afterward for leaks and there were none. The kit did the trick and the car shifts in and out of OD with no issues at all.

I am perplexed. I am guessing a seal possibly went bad somewhere, and not being really, really familiar with the car yet, I am needing some advice. There is no fluid trails or fluid on the ground where I park at.

I'm looking for sone guidance here. Thanks in advance!

 

use some engine cleaner ('gunk') and clean off the whole exterior of the transmission, then make sure its close to full, and drive it some, then look for fresh oil leaks. you also can get some fluorescent dye you put in the oil (ATF), and using a black light, the fresh leak will glow bright orange.

 

One common area for leaks is the cooling lines that run to the radiator. Right at the bell housing there is a clamp that holds the two lines. Over time the vibration wears through the line at this point.

Another typical leak is through the tailshaft. If your tailshaft bushing is worn out the seal there ends up failing. If this is the case, make sure you replace both the bushing and the seal otherwise the new seal will fail in short order.

Finally, check the coolant reservoir to see if there is any oil in it. There have been times the radiator fails and mixes coolant and trans fluid.

 

So, I've refilled the car with fluid and driven it about thirty miles or so. The transmission still slips even when full of fluid (and looking at it now I do see traces of ATF around the pan gasket).

I guess my question is - should I just find another AW70 or AW71 to put in it and swap the existing transmission out? Is there any way to stop a transmission from slipping once it has already started?

I just don't want to waste time putting a band-aid on something that will never be right when with a bit more time I can totally fix the problem.

Thoughts?

 

its either get your tranny rebuilt, or find another one, and the first choice is probably more expensive.

 

Given the mileage, I would look for a replacement tranny. When looking in the junkyard, try to get the lowest mileage trans you can find.

 

note also, you should be able to use the AW70/71 out of any 1989+ 740/940 *except* the 16V versions have an AW72 with different gear ratios.

you COULD use the AW70/71 out of an earlier 240/740/940 but you'd need to cut a notch in the bell housing for the LH2.4 crank position sensor

Not sure I'd put too much faith on odometer readings, as these odometers are notorious for breaking. A car that looks well maintained but was in a serious crunch would be your best bet.

 

Many times you can pick out cars with broken odometers as the trip odometer shows 000. Any car showing 000 on the trip odometer may or may not have broken odometer. On the other hand, it is fairly safe to assume a car that doesn't have 000 showing on the trip odometer has a working odometer.