Changing the transmission fluid

I drive a 2006 Dodge Sprinter, 3500 with dual wheels. When changing from park to drive, the gears would not automatically shift from first to second gear. The engine kept revving, so I stopped the vehicle, and started it again. No problem. I spoke with a retired mechanic (friend of mine’s father) and he said we should probably change the transmission fluid. When I called the dealer, he said they could do it but that he also saw problems arise when the fluid was changed on vehicles with high mileage (it has 225,000 miles on it).

Should I go ahead and change the fluid, or not?

Change it ASAP.

I agree with Whitey.
You should definitely try a fluid (and filter) change, but don’t expect it to work miracles if this is the first fluid change that you have done.

I change my fluid every 3 yrs or 30k miles (whichever comes first) and I have never experienced trans problems. Those who don’t change trans fluid on this type of schedule can look forward to trans failure any time after ~90k miles, and trans failure is pretty much of a sure thing for these folks by ~130k miles.

If you have driven this truck for 225k on the original fluid, I think that you should feel good that you have gotten much more out of it than the design life for a neglected transmission. If the trans does fail after the fluid change, it will not be the fault of the fluid change–despite old wives’ tales along those lines. If it fails shortly after the fluid change, the trans was going to fail anyway, as a result of long-term neglect.

When was the last change? That’s pretty important information you’re omitting.

If you’re lucky it may just be low on fluid. A common problem on the NAG1 transmission is fluid leaking from the wiring harness connector on the right side just above the pan. This vehicle doesn’t have a dip stick so you have to rely on a shop to check the level for you (or buy a dip stick). If you see that the transmission is leaking, have it repaired and change the fluid. Transmission fluid was to be replaced at 80,000 miles.

Woah there… Before you do anything, answer this:

1: Do you think the transmission is in limp mode??
2: Is the “Check Engine” light on??
3: Are you seeing a “System Under Voltage” message in the driver information center??
4: Do you have electric ventilation fans mounted on the roof of your Sprinter??

 On Sprinters equipped with electric ventilation fans on the roof, the fans are wired into the TCM (Transmission Control Module) power supply circuit.  The fans draw too much current for one relay when they turn on.  This causes a voltage drop across the transmission control relay, which causes a voltage drop to the transmission and creates a "Limp mode" condition.  The transmission will usually go into limp mode when the fans come on.

Could this be what you are experiencing??
If the answer is yes, let me know because there is a cure for this condition.



Would that be re-wiring the fans to pull power from another source? I’m really trying to understand the poor choice in using the TCM power circuit for an electronic module sensitive to voltage drops to run electric motors of any type, that cause voltage drops when the start up and when they run warm. Who was the rocket scientist that came up with that idea?

I would take transman’s advice. Running the electric ventilation fan power through the TCM Control Module is a bonehead idea. I’m sure any enlightened engineer would have figured out that fans can have many problems after they are operated for any length of time. This design is just asking for problems.


It is kind of screwey, I’ve seen worse. The fix for this is a relay and wire kit which when installed will isolate the fan circuit from the TCM power supply circuit.


First read transman618’s response.

… “he said they could do it but that he also saw problems arise when the fluid was changed on vehicles with high mileage”

 It is very common for a transmission to fail shortly after having the fluid changed.  But you need to take that one more step and look at why the transmission fluid was changed.  You will find in most all cases, the transmission was not acting right so the owner changed the fluid (usually well over 100,000 miles.)  The problem was not caused by the fluid change, rather it the fluid was changed because the transmission was damaged because no one changed it over those many miles, and waited too long.  

The transmission was damaged because the fluid was not changed soon  enough to prevent the damage.  If you had changed the fluid at say 40,000 miles, it is likely the transmission would still be just fine.  It is criminal that the manufacturers do not put a reasonable recommended fluid change interval as a they do with the engine oil, but they don't.  I'll bet they sell a lot of new cars that way.