Fluctuating trans oil level

[wwheeler]

Here is one that is making me crazy. When checking the auto trans oil level, the fluid level on the dipstick will vary from no reading on the stick to 1" above the full line. I always check the oil level with the engine at idle on a level surface, trans in park and the fluid warm to hot. In a matter of five minutes, the reading on the stick can vary that much (checking every 30 seconds). 

I have had this car three years (changed fluid and filter when I bought it) and the oil level has been extremely consistant until two weeks ago. That is when the double acting solenoid was replaced as was the trans breather. The solenoid was lazy and causing very erratic shifts. At least that is fixed! The trans now shifts great, downshifts smooth and kick down works as well.

The mechanic also talked me into adding "Cerbond" into the trans to improve shifting quality. This guy is a well known mechanic in the area so I decided to try it. When I got the car home, I inspected the oil level. It was perfect and not quite to the full line. It stayed that way for two more days and then the fluctuations started. Thinking that the additive was causing this, I changed the oil in the pan and converter and put a new filter on. I didn't see anything bad in the filter. I added in exactly the same amount that I took out and seemed to match the BBB at just over 4 quarts.

The problem still persists! The breather is new from MB but I am going to switch out with the old one and see what happens. Anybody else have any ideas?

[graphic66]

Try checking with the car in nuetral, not park.

[wwheeler]

I did the fluid check in neutral as well.

Luckily, the problem somehow resolved itself. Two nights ago when I started the engine, the fluid level went very low on the stick as it has. Lately, the level would rise way above the full mark as the ENGINE warmed up. This time it stayed down. I felt brave and added a total of 6 ounces to bring it to the low line on the stick which should be right when the trans is cold and engine running at idle.

I let the engine run for about five minutes and the level never changed! That's the first time that has happened in two weeks. Tried it again last night and worked just as well. So a test drive this weekend will confirm if it is fixed. I talked to a transmission guy about it and he thought the CERBOND may have clogged or stuck a valve in the valve body that affected the fluid flow into the pan. The transmission always worked well eventhought the level was fluctuating. Strange!

[wwheeler]

I was a little premature in declaring a resolution. The trans fluid had been constant for several days so I decided to put the new breather back on in place of the old one. As soon as I did the switch and started the engine, the trans fluid disappeared on the stick !

I stopped the engine and quickly install yet another new breather I had just bought. Started the engine and the oil level returned to normal.

So the final conclusion is the breather caused the fluid fluctuations. That was a week ago and the level has been constant. Both breathers seemed about same when I blew into them. Must be something inside the defective one.

[wwheeler]

So much for final conclusions.....

The replacement new breather started doing the same thing. So I did a test. I waited until the fluid disappeared on the dipstick with the engine running. Once it did that, I stopped the engine and checked the fluid and it of course had none on the stick. In less than a minute, I removed the new breather. Vola! The fluid returned on the stick and at about the correct level. So the problem is the breather but why are two new ones faulty?

Picture #3346 shows the 22 year breather (right) that always worked, and a new breather (left). The cap on the new one is clearly machined whereas the old one was stamped. Picture #3338 shows the inside of the new cap that has a slight cone torwards the middle and is smooth. When the cap sits on the body, it nests on the taper in the body and creates a seal. Because the old one is stamped, the indentations on the back side of the cap would prevent a seal ever forming.

If you blow into the old breather, it releases air regardless whether the cap rests on the body or not. The new breather releases air, but when the cap rests on the body, it seals the air. So the two are NOT the same part. Similar, but not the same. In my old Jan. 1968 parts book, they list a 111 260 00 58 breather for an auto trans. The EPC lists that now as only for manual transmissions.

I am going to use my old breather for now, but want to know if anyone has had a similar problem?