Coasting or Drifting ???

[radar doctor]

if you are going down the road say 60 mph in a 03 Automatic 48 transmission and you come to a big Hill... will it hurt anything to slip the trany into neutral and Coast down a long hill???Dont want to tare any thing up but i haven't noticed any problems on a 2 mile down hill grade. . Any transmission people out there??/

 

[y-knot]

some trucker call that the Teiwania Over Drive, which is illegal, because their trucks are always suppose to be in gear while moving. To me, I wouldn't do it, and why would you??? You are not saving any fuel? I would think that by being in gear, it would receive better lubrication, that's just me.

 

[GerryDrake]

I wouldn't because at idle, the power steering pump is not able to provide as much assist as at higher RPM, and the vacuum for power brakes is similarly at its lower end of output. Presumably both of these will be adequate, but if you suddenly need a whole lot of either (or both) I would much rather be in gear. . . and y-knot. . I love your spelling of Tijuana. .

 

[Gary - K7GLD]

Up on Sierra I-80 on the downgrades, signs are posted on downgrades advising truckers to "let'er drift" - sorta surprised me, but there they are...

 

[Forrest Nearing]

I wouldn't do it on an automatic...

 

[BStoecker]

As I understand it, you need to leave it in drive to keep the transmission fluid pumping to keep the transmission temps down. The pressure drops when you put it in neutral and can let the temps climb. This is an easy way to wear out an auto prematurely.

 

[jcarey]

On our the 04. 5 48RE, when you take your foot off the go pedal, the engine drops to idle, unless you're locked up. I was pleasantly surprised to see that. With our VW diesels with a manual trans I always coast in neutral. Testing on trip back and forth to work, I can coat about 4 out of 12. 5 miles.



For an auto, like stated above, I wouldn't put it in neutral while the wheels are moving.

 

[GerryDrake]

Originally posted by Gary - KJ6Q

Up on Sierra I-80 on the downgrades, signs are posted on downgrades advising truckers to "let'er drift" - sorta surprised me, but there they are...

Been a long time since I was there, but I DO remember those signs. Never seen them anywhere else (not that they aren't) . . Curious if they are only on moderate downgrades that have a long level or upgrade at the end?... I still like having the various pressures up for brakes, steering, etc. so won't be doing it.

 

[NIsaacs]

Like Gerry Drake said, the "Let'er Drift" is for when road conditions permit. It means you can "put her in the big hole" and coast up to speed, not take it out of gear. I would not advise to do that. On high profile vehicles, the faster you go (within reason) the less brakes you need. Even on 6% grades if the road is straight, you can run up to 75mph (az spd limit) with just the "jake" and little or no brakes. However in lower gears at 50 mph you will need your "jake" and lots of brakes.



"IF IT AIN'T CUMMINS POWERED, IT AIN'T A TRUCK"



"NICK"