First I did a search and found alot on tranny flaring, but did not see anything pertaining to this.

My friend has a 1989 300E sedan. She is away on business (in the car) and phoned me to try get some information here.

I have driven the car before and the transmission shifts smooth (not harsh/firm shifts, but it does not slip either).

Today she accelerated from a stop making a left turn and the car kinda went up a slight grade while doing so.... the car was to shift while the car was still in the turn position and when it was to shift into 3rd (which was only about 20 mph she said), the cars engine RPMS raced up like the car had went into neutral, but only for a moment, then it went into 3rd and there were no other issues with it today - shifts smooth, no flaring.

My first thought is its either low on fluid or the filter needs changing or both. She said the fluid level looked OK and the tranny fluid was pink (which is normal), but it did not smell like other tranny fluid she had smelled (but who knows what she is referring to). Maybe MB tranny fluid smells different that other tranny fluid? OR maybe some adjustment is in order?


The car has 162K miles and has always been well serviced.

Any info I can relay to her appreciated.

That does sound like the pickup got uncovered enough to pull in a little air. Some of the sportier cars actually got a trans filter that has two openings and a g-force actuated slider that kept the pick-up covered under high g-forces.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

Hate to ask a blatantly sexist question, but does "she" really know how to properly check the fluid level? On level ground, with the car running, warmed up etc?

I have found that my 300SE is VERY sensitive to trans fluid level. A quart low and you start slipping. In fact the one time it got low, it felt like gears were breaking inside. Added a quart, and no problems since.

Actually yes. lol. She came back today and she said it only did it once more and actually this time when she was pulling from a stop at a slight grade, it flared from 2-3. She checked the fluid and as did I (in park @ idle, normal engine temperature, on the level, and it is actually about 1/2 way between the bottom of the stick and the lowest level of normal.

SO... what would that make it - about a quart low? 1/2 quart? Is this the likely culprit for the flaring from 2-3? Also, what type fluid for the 300 I-6 Mercedes? MB only fluid, or will Dextron work?

I looked under it and seen no leaks whatsoever, so why would it be low? PO did not fill it completely on the last change?


Thanks!

Check for low fluid - sounds like the fluid sloshed to one side during the turn and caused an air pocket or dry condition. My vote is for low fluid.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Yes, its about 1/2 way below the lowest normal line and the bottom of the stick. Its not leaking though, so not sure why it was low.

Low fluid might have caused the sychonizers (?) to overheat

I don't really know if that is a low enough fluid level to be the issue in and of itself. It wouldn't hurt to add some. I forget the fluid spec, I had the guy at NAPA x-ref it when I had this issue and he gave me a compatible fluid. If I had not been as close to being stranded as I was, I would have gone the extra mile down the road to get the MB fluid.

Now, let's suppose you had a clogged up filter. Perhaps the combination of a slightly low ATF level and a clogged up filter could create the symptoms you are describing.

Have you checked the vacuum line to the shift modulator? Maybe you have a crack in it that only opens up in certain situations. Doubt it, but worth a check.

Even though we have the same engine, I think our trannies are different. On mine, when the ATF got low, I started having problems starting from a stop especially on uphill situations. At first, I just got an extra clunk. It would take a split second to engage the tranny. It felt quite a bit like a shot motor mount, you know - that extra thud when you hit the gas. As it progressed (within a day), it got to where it felt as if gear teeth were shredding. A horrible sensation. It really did feel like gear teeth slipping. I expected the thing to fall apart going down the road.

Added a quart of ATF, and I have had nothing but smooth shifts ever since.


tp

"Low fluid might have caused the sychonizers (?) to overheat"


Man, and I thought I was shooting in the dark.

Thanks.

Well, I have never had to add any fluid in any of my Mercedes transmissions nor ever had it changed, so what type of fluid should be used? Dextron III OK, or is that a no-no? MB fluid only?

Its also kindof a question for me, as I am going to soon have my transmission fluid and filter changed on my 300SEL. I guess I could look in the owners manual.