Benificial for an auto tranny??

Status
Not open for further replies.
Originally Posted By: Kawiguy454
It never ceases to amaze me that a certain percentage of responses always involve how badly things will go wrong when I knowingly take an action then somehow forget where I'm at and what I'm doing resulting in a catastrophic chain of events. Must be some of you had a nanny growing up to take care of your fails before they happened.

Disclaimer: If you on meds or just stoopid ...don't try this at home it could lead to an epic fail.

Sitting at a light stopped the 1st gear clutch pack is engaged fully and the torque converter is slipping. The fluid temperature rises probably 50 degrees in a minute. If it is stop and go traffic the high temperature will soak in and never go down to normal cruising temp until after you're cruising again. The slipping tq converter is why we put transmission coolers on towing vehicles and race cars.


FI have a transmission temperature gauge on my truck and it sits between 175ish and 186. A T stat maintains that temp, which I think on my transmission is computer controlled because it seems to have a mind of its own.

After a highway run if I sit I can watch the transmission temp tick down a degree at a time.

Again its 2015...
 
Last edited:
Originally Posted By: hattaresguy
The entire shifting out of gear when in park is an out of place discussion to have about modern vehicles.

Shift cable? My transmission has a wire going to it....


Absolutely hilarious. And true of my truck also. If you have a cammed up 1970 Chevy it might make sense...
 
Originally Posted By: hattaresguy

Shift cable? My transmission has a wire going to it....


The row of 2015 Silverados in front of me do have cables...in fact, every one of them uses the same p/n whether it's an Allison or 6L80E. What can be assumed of one vehicle can't be assumed of another.

You guys are missing my point though. My point was when something is used in a kind of an abnormal way (and shifting an AT at every light isn't the typical way to use an AT), you may experience unexpected wear on parts you would normally never think about. I have never replaced a shift cable either, but I do sell them daily, which is why that example came to mind. Not to mention all the cars I have worked on over the years (not mine, but all brands including Japanese) that had a way out of adjustment gear indicator or other shifter issues. A Ram may not have a shift cable, but it surely has other components that may not last forever if used in an abnormal way. People use their cars in all kinds of weird ways and break all kinds of weird stuff - I see it daily.
 
Originally Posted By: hattaresguy
Originally Posted By: Kawiguy454
It never ceases to amaze me that a certain percentage of responses always involve how badly things will go wrong when I knowingly take an action then somehow forget where I'm at and what I'm doing resulting in a catastrophic chain of events. Must be some of you had a nanny growing up to take care of your fails before they happened.

Disclaimer: If you on meds or just stoopid ...don't try this at home it could lead to an epic fail.

Sitting at a light stopped the 1st gear clutch pack is engaged fully and the torque converter is slipping. The fluid temperature rises probably 50 degrees in a minute. If it is stop and go traffic the high temperature will soak in and never go down to normal cruising temp until after you're cruising again. The slipping tq converter is why we put transmission coolers on towing vehicles and race cars.


FI have a transmission temperature gauge on my truck and it sits between 175ish and 186. A T stat maintains that temp, which I think on my transmission is computer controlled because it seems to have a mind of its own.

After a highway run if I sit I can watch the transmission temp tick down a degree at a time.

Again its 2015...


This. On my F150 it also has a trans temp readout in the instrument cluster. Usually maintains a narrow range of 190-200. I've only seen over 200 a few times, one of which was after a long climb with our 8k+ camper attached this weekend. It seemed to peak at 206 and quickly came down. Even in 30+ minutes of stop and go this weekend with the camper, the temp stayed @ 200. Nothing special done to the transmission other than Tow/Haul mode.

I seriously doubt you would get a 50 degree rise in a modern car in drive even with a brick on the gas pedal and 2 feet on the brakes at an average stop light.
 
Originally Posted By: 440Magnum
Originally Posted By: NHGUY
I'm surprised by now they haven't come up with a computer scenario for that...sit at a light for more than 30 seconds,and the computer will automatically shift the trans to neutral,step off the brake and it re engages the transmission to the gear range chosen on the shifter.


If it actually saved any fuel to do that, they would have done it. Heck, there are now a number of car models that SHUT OFF under those conditions and restart when you touch the gas! Bottom line, as others have said, modern torque convertors practically disengage at idle anyway, and so almost no additional fuel is burned (and almost no heat generated) from leaving the trans in gear. On an older car with a carb, big cam, fast lopey idle... yeah, it saves a lot of heat generation to drop it into neutral if stopped for more than half a minute. But not on anything remotely modern.


They have done it! Heavy commercial trucks and semi's with automated manual transmissions and the Allison TC-10 automatic go into neutral every time the truck stops. Not even a 30 second delay time! Once your foot leave the brake on an automated manual, it engages a internal brake that holds the vehicle for 3 seconds while it puts the trans into gear and engages the computer controlled clutch. On the Allison, once your foot leaves the brake, it engages the automatic just like putting into drive.

It has indeed long been documented as a fuel saving feature. But like most things, the car and pickup folks are slow to join the party.
 
Originally Posted By: TiredTrucker

They have done it! Heavy commercial trucks and semi's with automated manual transmissions and the Allison TC-10 automatic go into neutral every time the truck stops. Not even a 30 second delay time! Once your foot leave the brake on an automated manual, it engages a internal brake that holds the vehicle for 3 seconds while it puts the trans into gear and engages the computer controlled clutch. On the Allison, once your foot leaves the brake, it engages the automatic just like putting into drive.

It has indeed long been documented as a fuel saving feature. But like most things, the car and pickup folks are slow to join the party.


That is true of all DCT transmissions but i think this thread was mainly about traditional, torque converter based ones. The DCT has to go into neutral (or equivalent with clutch engaged) other wise you'd wear something out very quickly.
 
Status
Not open for further replies.
Back
Top