gear damagement with mountain

[cimbro]

Hi! Having the steptronic instead of the manual gear, I would ask you if I avoid the tear of the gear starting in mountain with high slope.
Usually with manual gear, when you start with slope you use a lot the friction, now without do I have damagement or nothing? Or when I pull a very heavy wheight? What could be damaged?
Thank you

[withidl]

With the Steptronic you have an automatic transmission designed so that the driver can choose and hold the transmission in any specific gear. Other than that it is an automatic transmission which uses a torque converter (fluid coupling which can multiply engine torque) in lieu of a friction clutch. The torque converter, unlike a friction clutch, does not physically wear with use.

The only friction within a torque converter is fluid friction which will build up heat within the transmission fluid, but this is dissipated via the fluid being circulated through the engine radiator (separate tubing).

The only thing you do not want to do is hold the vehicle on a slope (not moving) with the throttle as this keeps the transmission torque converter in a "stalled" condition which can rapidly build up heat within the transmission fluid faster than the radiator can dissapate it.

As to pulling a heavy weight; I have pulled an 8,300 pound 31 foot travel trailer for over 28,000 miles with my 2001 4.4i which now has about 82,000 miles on it.

[cimbro]

Originally Posted by withidl

With the Steptronic you have an automatic transmission designed so that the driver can choose and hold the transmission in any specific gear. Other than that it is an automatic transmission which uses a torque converter (fluid coupling which can multiply engine torque) in lieu of a friction clutch. The torque converter, unlike a friction clutch, does not physically wear with use.

The only friction within a torque converter is fluid friction which will build up heat within the transmission fluid, but this is dissipated via the fluid being circulated through the engine radiator (separate tubing).

The only thing you do not want to do is hold the vehicle on a slope (not moving) with the throttle as this keeps the transmission torque converter in a "stalled" condition which can rapidly build up heat within the transmission fluid faster than the radiator can dissapate it.

As to pulling a heavy weight; I have pulled an 8,300 pound 31 foot travel trailer for over 28,000 miles with my 2001 4.4i which now has about 82,000 miles on it.

Thank you for your help and compliments for the very good knowledge of the technical of the X.
So, as you told, the auto tranny doesn't has wear, why in Italy where I live, after the Km. 80/100.000 many people have to change the complete gear! It's awfully expensive and make bad reilability of this beautiful car (sorry for my bad english), bye

[cimbro]

Do you think that a city use where the gear is continuously changing or a mountain use make a faster wear?

[withidl]

I believe the city stop and go constant shifting is the problem, not the mountains.

That being said, unless I'm in a hurry (rarely am), if I'm in the city I use "Manual" mode 3 gear to start off (light throttle) and leave it in 3rd gear using the engine compression to decelerate to the next stop. This keeps the tran$mi$$ion form shifting (uses only the torque converter) thereby reducing clutch wear.

I also lighten the throttle (as you would with a standard clutch/transmission) in anticipation of shifting to further minimize clutch wear (done that all my life).

When in the mountains, unless your in a hurry, use Manual mode 5th/6th gear to keep the transmission from "working". The 4.4i engine has sufficient power to pull most grades in 5th/6th without the need to downshift. Do a search of this forum for my comments on how I use the transmission when I'm pulling my travel trailer for more detail.

[cimbro]

Originally Posted by withidl

I believe the city stop and go constant shifting is the problem, not the mountains.

That being said, unless I'm in a hurry (rarely am), if I'm in the city I use "Manual" mode 3 gear to start off (light throttle) and leave it in 3rd gear using the engine compression to decelerate to the next stop. This keeps the tran$mi$$ion form shifting (uses only the torque converter) thereby reducing clutch wear.

I also lighten the throttle (as you would with a standard clutch/transmission) in anticipation of shifting to further minimize clutch wear (done that all my life).

When in the mountains, unless your in a hurry, use Manual mode 5th/6th gear to keep the transmission from "working". The 4.4i engine has sufficient power to pull most grades in 5th/6th without the need to downshift. Do a search of this forum for my comments on how I use the transmission when I'm pulling my travel trailer for more detail.

How can you climb up the mountain with manual in 5th gear? And how can you start in 3rd? I think in this situation the slippage of the torque converter make hot temperature of oil and the continuous slippage make more wear!?

[withidl]

Originally Posted by cimbro

How can you climb up the mountain with manual in 5th gear? And how can you start in 3rd? I think in this situation the slippage of the torque converter make hot temperature of oil and the continuous slippage make more wear!?

My 2001 4.4i has a 5 speed transmission. If you have the 6 speed the principal is the same but the shift speeds will differ.

Above 60 mph the 5 speed transmission torque converter "locks-up" (does so in 3rd, 4th & 5th), that is it has a clutch which the computer controls which causes the torque converter to go into direct mechanical drive (just like a standard transmission). As long as your in "Manual" mode, above 60mph the transmission will remain in direct mechanical drive which is its most efficient mode. Incidently, when the torque converter "locks-up" you will preceive it as a shift, but it is not a true shift.

In climbing the mountain if you are in "Manual" mode you can select the gear you want to use. If you select 5th, the transmission will remain in 5th down to about 38 mph at which time the computer will downshift it to 4th (the computer will also unlock the torque converter at about 60 mph).

To keep the transmission from "working its clutches" YOU SHOULD SELECT THE GEAR in "Manual" mode that keeps the engine above about 2,000 rpm; so if the tach aproaches 2,000 rpm while you are in 5th manually shift the transmission into 4th.

To starting off in 3rd put the transmission in "Sport" mode, then toggle the shifter up to 2nd and then 3rd before starting off. The computer will hold the transmission in 3rd since it is programmed to do so to allow you to start off in icy conditions without putting a lot of torque to the wheels.

Torque converter fluid slippage will cause the fluid to heat up, but above 60 mph the torque converter is "locked-up" so there is no fluid slippage, and again, fluid slippage is NOT the same as clutch slippage. With clutch slippage (when shifting) there IS physical wear; with fluid slippage there is heat induced into the fluid but there is NO physical wear.

The transmission and its cooling system is way over build and can handle the heat induced into the fluid. I have climbed the continental divide (over 10,000 feet) here in the United States, using "Manual" as described above, 3 times pulling my 31 foot 8,300 pound travel trailer (assembly weighing over 14,000 pounds) with no problem what so ever, so the transmission can take it.

[X5Flyboy]

May I suggest you not use the cruise control towing up mountains - That will help the transmission and prevent it from doing a hard downshift - towing a light trailer, I got 18mpg with my '06 4.4, even going over the Rockies at 70 mph

[withidl]

Originally Posted by burkleymh

May I suggest you not use the cruise control towing up mountains - That will help the transmission and prevent it from doing a hard downshift - towing a light trailer, I got 18mpg with my '06 4.4, even going over the Rockies at 70 mph

I disagree. I use the cruise control 95% of the time when towing my 14,000+ pound assembly in "Manual" mode because it's response is more acute than mine and in "Manual" mode the cruise control will throttle the engine to the max WITHOUT down shifting the transmission. If a grade can't be pulled in 5th, I disengage the cruise control and manually change to 4th before I drop below 60 mph to keep the torque converter locked-up and re-engage the cruise control. When I have to use 3rd I usually throttle the engine myself. I use the fuel consumption guage to determine engine loading and only up-shift when the guage is indicating 20+ mpg as that tells me the transmission is unloaded and can be shifted without stress.

My mileage with the Airstream travel trailer (8.5 feet wide & 9+ feet high), in a no wind condition, on level ground, averages about 11 mpg at an indicated 70 mph (GPS actual is about 66 mph).