Rollback in Drive, on a hill, nose pointing up at a stop?

[kkanuck]

Just wondering if others find the same as me.....

If I am on a hill, at a light, with my front end pointing up the hill....if I do not press the brake, the Sprinter will roll backwards almost like a stick shift....

Is this normal of the Sprinter transmission?

I also have found that when it is cold, at startup, and you put it in drive, sometimes it will rev up a little, almost like neutral and then engage and start moving forward? Is this also normal.

I have 18K miles on her.

Many Thanks for any tips

[KenB]

All sounds pretty normal to me... Auto Trans use a torque convertor and at lowest RPM (idle) they don't provide much "push" forward to hold you on the hill. In fact some, like Mazda, will tell you to NEVER hold the vehicle on the hill with the Trans/accelerator as critical transmission components will heat up and damage will accrue over time.

On Small rises mine will hold without brakes applied at least for a short time. this is as much as I expect from an auto trans. The "lock-up" mode of this trans is only available in 2nd-5th, NOT in 1st. That is why the Sprinter gets such good engine braking in 4th, 3rd, & 2nd...

1st gear is pretty good at braking because it is a LOW gear, but it is a bit mushy because the lock-up is not engaged. This is good, as it keeps the sudden engagement of 1st gear during engine braking from being an impact instead of an evenly applied force. (Also, diesel engine compression is HIGH so the engine braking effect is much more prominent that on lower compression gasoline engines).

The computer is in control of the RPMs especially at IDLE and engaging the trans is likely to make the computer anticipate the additional load you are adding to the system and sets the IDLE up a bit so your engine does not stumble when the engine starts pulling against the torque convertor. It should not be very noticeable... but your system may be on one edge of the envelope of engine control where another may be on the other and slightly stumble prior to picking up power to compensate for the trans being engaged.

Hope this helps you,
KenB:cheers:

[BaywoodBill]

As KenB says, "Auto Trans use a torque convertor and at lowest RPM (idle) they don't provide much "push" forward to hold you on the hill. "

But your question brings forth another question and that is, why did you ask?

By that I mean, have you had experience with an automatic transmission that actually holds on hills? Or are you referring to some deterioration you have experienced recently (to your hill-holding ability)?

[talkinghorse43]

Is this normal of the Sprinter transmission?

I also have found that when it is cold, at startup, and you put it in drive, sometimes it will rev up a little, almost like neutral and then engage and start moving forward? Is this also normal.

Neither one is normal for my '02. In fact, mine will hold what I consider steep grades at idle w/o the application of brakes. This is something I've never experienced with another auto tranny.

Maybe your fluid level is low? Since the fluid level is so sensitive to temperature that might explain the delayed activation when cold. Also, the troubleshooting section of my '03 service manual says low fluid level is a possible cause of this.

[talkinghorse43]

(Also, diesel engine compression is HIGH so the engine braking effect is much more prominent that on lower compression gasoline engines).

Not so. A diesel engine w/o an exhaust brake or a compression brake has very little engine braking. While it's true diesel compression is much higher than gas, an unbraked diesel acts much like a spring with the expansion in one cylinder driving the compression in the other and so on. On the other hand, a gas engine has good engine braking capabilities because the inlet manifold runs at vacuum with the throttle closed (diesel engine intake pressure is at atmospheric, or above).

I agree the Sprinter has good engine braking capabilities, but I believe this is due to the turbo inlet vanes being used as a valve (exhaust brake).

[boatmangc]

Mine does it, rolls back I mean 1400 miles on an 06. It goes in for a checkup (alignment, trans fluid level and frosted left headlight) a week from today. Maybe it will stop when they top off the tranny

[kkanuck]

let me know what happens with the fluid level check?

Did they charge you to check? Was it low? Did they add fluid, or change all together?

Thanks for any tips,