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View Full Version : My 2003 T1N fails to shift automaticly


Lin-z
01-22-2014, 07:39 PM
I just found this Forum and I am becoming frightened by all the things I am reading. I thought I bought a van that was problem free. It has been for 10 yrs. but now the tran. won't downshift automatically. It has 90,000 miles, normal service and a tran. fluid changed recently. Can one of you smart folks point me in the right direction or am I headed for the Mercedes Dealer? Thank you in advancelinzlabit@gmail.com

Aqua Puttana
01-22-2014, 08:23 PM
Is the MIL aka CEL light on?

Does the engine seem to still have the power it always had? If you have a boost leak or other issue which the computer notices then it can set LHM Limp Home Mode. That limits power. Often people notice first that the vehicle doesn't shift properly when in LHM.

Whatever you do don't let someone jump to telling you that your turbo is bad. The Sprinter Garrett turbocharger seems very reliable.

Information, not a diagnosis. vic

autostaretx
01-22-2014, 09:48 PM
I just found this Forum and I am becoming frightened by all the things I am reading.Which came first, the problem or the reading?
I thought I bought a van that was problem free. It has been for 10 yrs. but now the tran. won't downshift automatically. It has 90,000 miles, normal service and a tran. fluid changed recently.
Again, which came first? The problem or the fluid replacement?
If the fluid was changed *before* the problem appeared... well...
Did the fluid-changer (who did it?) replace the transmission electronics connector's O-ring?
(or the whole connector) Are there signs of leakage there? Have you checked under the driver's seat to see if transmission fluid has wicked up the cable harness and contaminated the TCM (transmission control module).
Can one of you smart folks point me in the right direction or am I headed for the Mercedes Dealer? Thank you in advancelinzlabit@gmail.com
You probably DO want to visit an MB or other Sprinter-equipped shop to have the diagnostic trouble codes read with a proper tool (not a standard OBD scanner). It will reveal what the TCM thinks the problem is (and which it hopefully remembered for future readouts).

good luck
--dick

sailquik
01-22-2014, 11:30 PM
Do you also know what fluid was used when your transmission was serviced?
Did they "flush" your transmission with a "flushing machine" that runs your fluid through a pump and
filter (really a bad idea for any Sprinter NAG-1 transmission).
Did they replace < 6 quarts of fluid....or 9 quarts of fluid (includes draining and refilling the torque converter).
Does your transmission not downshift automatically when you come to a stop....?
Does it upshift normally when placed in "D" (Drive)?
Does it simply not downshift if you slam the pedal to the floor?
Will it downshift for you if you try to manually downshift it?
It will not downshift into any gear that would over rev your engine, so you have to be going a speed appropriate to the gear you
are trying to downshift manually into.
Did you purchase a transmission dipstick to check the fluid level?
Vic (AP) and Dick (autostaretx) have it right, but before any of us can really provide you any real guidance, we need the whole
picture of what your Sprinter is doing.
Hope this helps,
Roger