Letting the truck idle in drive
 

I am wondering if it hurts the tranny to let the truck idle in drive with the parking brake on? I am new to autos so I am not sure. I have been letting my truck idle in neutal to warm up before driving. EGT's in high idle are only 250*. When I put it in drive the EGT's are 425*. So I figure it will warn up faster that way. But will it hurt anything?
TIA

I wouldn't do it. Take the truck to the dealer and have them flash the high idle feature that's controlled by the cruise control buttons.

MikeyB

Not availble on the 03. I use the power pup PTO feature to idle up to 1300 rpm. Still only 250* after the grid heaters finish cycling on.

In drive you are generating heat when the TC is slipping. While it is not going to kill the tranny anytime soon, it certainly is not doing any good. If I'm going to be idling I use N or P.

I wouldn't want to run the risk or liability of idling it in gear. Get a stick to prop up the pedal instead.

But the best way to warm up our trucks is to drive off gently after oil pressure stabilizes.

Hey all I have a 2003 and honest to God it has a high idle. Now it hasn't been cold enough down here but last year when we got snow and ice it worked. I had to do nothing. I had my Jake Brake off so it wasn't that. Here's how it went. I forgot to plug the truck in. I went out the next morning to snow and ice. I started her up and went back inside to find my ice scrapper to scrape off the ice and use it as the old "prop the go pedal " trick stick like I use to do on my 2000. Well when in the house I heard the truck idling high. I went outside expecting to shoot someone trying to make a quick get-a-way. Well to my surprise it was idling around 1100 rpms. After a few minutes I pressed the brake and it went off. Well I tried it again and without fail it would work. It would only come on if I left the truck unplugged and it was around freezing. I start the truck up, about 3 minutes later the idle would rise to 1100 rpms and stay there until I press the brake pedal. So long as I had the parking brake on, exhaust brake off, and truck unplugged overnight, it would work. For you guys up north try it out. Don't forget to NOT plug your rig in overnight. It never worked for me if I did.

Hey Jr, all the 3rd gen trucks have that feature. When its real cold, it'll even high idle itself when its "warmed up" and idling for two minutes.

That is the standard high idle. It will ramp up to 1000 RPMs when the coolant temp is below a set temp. The TSB Enabled high idle allows the cruise control buttons to ramp the idle up to 1100 to 1500 rpms. 1000 RPMs IMHO is not enough to warm the truck up. The TSB does not apply to 03's...so a stick or aftermarket high idler is you only option for higher RPMs.

I thought that TSB worked on all 3rd gen trucks with an auto.

Not sure about the 48re, but if it shares the attributes of a lot of Dodge transmissions you should set the parking brake and idle in neutral. Extended idle in park is not a good idea becuase the fluid in the trans does not circulate.

Didn't know that. :confused:
Best bet is to either use the block heater or just drive off. Personally I wouldn't let a cold diesel engine idle for very long. Wets the cylinder walls and contaminates the oil with diesel fuel.

MikeyB

Another good way to warm up is to turn on the exhaust brake at idle when the engine is cold. This makes the engine work a little bit harder and warms it up. I don't know if the brakes for the Dodges come with that feature or not. My Isuzu NPR diesel has a button on the dash to warm it up by turning on the brake. Cool.

Wetspirit

No exhaust brake:(

Have you tried a heater pad on your transmission pan? I have them on my oil pan, transmission, and under both batteries. Along with the block heater all the important start parts stay warm.

Cold,

There is no way you'll hurt the tranny by idleing in gear. They get hurt by getting too hot when working hard or by putting too much torque through them. Just make sure you don't "hurt" the front of the truck by having it drive off.

Wetspirit