My fathers 99 E240 i beginning to develop a problem with the automatic.
Sometimes it hesitates while upshifting, and instead of shifting it just's
revs the engine about 500 rpm's and then shifts when rpm's have dropped the
500 rpm's down to what it was. Also when coasting at slow speed and if you
then press the pedal hard it's a clunking noise/vibration when it engages a
gear. When accelerating hard to redline it seems to take some time tho
upshift. It upshifts and revs drop from redline and 0.5 seconds later you
can feel the gear engaging by a clunking/vibration and a "kick in the back"
Hope this doesnt' mean the transmission is going bad? Perhaps a fluid change
would help? This is the 5 spd auto. Car's only done 60K
Thanks in advance.
I just underwent a similar set of circumstances. Delayed upshifts - "kick
in the back" REALLY hard shifts when it finally did shift - etc. You didn't
mention cold starts but in my situation it was most pronounced during warm
up - after a cold start.
Forget the fluid change. It is a sealed transmission and the fluid is in
for the life of the trans.
In my case they were reluctant to physically dig into the transmission,
thinking the problem stemmed from faulty programming in the trans computer.
They explained to me that the computer was programmed to delay initial
upshifts to help warm up the catalytic converter. They inserted all the
latest programming updates but the problem still existed so they reluctantly
opened the transmission itself. Inspection did not reveal anything
obviously broken or badly worn but they wound up replacing the sun gears and
several other items.
It would have been a hideously expensive undertaking except for the fact
that Mercedes picked up a large share of it under what was called "Customer
Goodwill". My share was under $900.00 US.
I hope your situation turns out to be simpler and less costly.
I have noticed that that it's not as willing to change up when engine is
cold, wich by the way seems ridicilous to me that they programmed it that
way, when engine oil is cold the least you want is a lot of revs. When i
think about it it might be that the problem is worse when engine is warm.
It's an itermittent problem. Perhaps i could be the computer. Is it the same
one that mangages the engine? Engine has been stalling and been difficult to
start when it's cold. Altough it hasn't happened since we put som condense
remover in the fuel tank, that may just be a coincidence.
Why is the trans sealed for life? Same oil for 15-20 years and possibly
2-300 K miles doesn't seem like a good idea to me.
I had a imminent overheat of the tranny on my 1999 E-220 CDI this summer
hauling my camping trailer over a mountain pass in very hot weather. this
caused the entire gearbox to quit working for a while, but after it had
cooled for a while everything was ok. and I could continue the trip (a
little more careful on the throttle) I ended up in northern Germany where I
contacted the local MB dealer, and they said that MB INITIALLY said the oil
should not be changed, but that they now had gone back on that, and
recommend oil change every 100-120k km.
He said that what had happened to me was that the transmission had reached
dangerously high temps. and the electronics had bypassed the oil to save it
from burning up. It should not affect the operation of the transmission
(unless it happens often). My cure was to install a thermostat controlled
oil cooler in adition to the original one after I had the oil and filter
The synthetic fluid used in these 'sealed for life' gearboxes is only
rated for 100,000 mile use by the manufacturer/blender. Perhaps
Mercedes and ZF were a bit cynical when they specified zero oil
changes because if the fluid was good to 100,000 and deteriorated
below spec steadily from then on, most users would get 150,000 miles
out of the transmissions before they failed terminally. Perhaps they
thought this was acceptable initially but now they have found that
more drivers reach high mileage with their cars than they had allowed
for, thus a change in policy to recommending a fluid change *every*
60,000 to 100,000 miles.
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