I was at a local trans. place getting another trans for my metro looked at. I got to talking to the mechanic and he said that if you idle your auto dodge truck to long that it will mess up the trans. He said that if it is in park it will not circulate fluid but if you put it in neutral that it would circulate the fluid. He said that is the reason that you have to check the fluid level with the truck running and in neutral. I was just wondering if anyone knows anything about this or is this guy full of ##it. I don't think that they work on many bigger truck trans. they seem to be a smaller vehicle repair shop.

 

He's right, if you are going to idle for a while, put it in neutral. The fluid wont circulate in park.

 

He's right about the ATF flow. A stock 48re does not flow ATF when in park. I haven't heard of anyone's trans overheating because of it though.

 

I've never heard of that either. If the pump isn't running in park, how would it overheat?

Nick

 

I smell something here!
How could the pump not be working when in park?
It is coupled directly to the engine is it not?
On every other tranny in the world the only difference between park and neutral is the mechanical pawl that locks on the output shaft dogs when in park.
Is there some other secret here?
If this is indeed true I will idle mine in neutral but I dont like that idea much as I live in an area where park brake cables like to freeze up on you.

 

The fluid does not circulate in park.
When I warm up the truck I put it in N to circulate and warm the fluid.
I also cool the truck down in N so the fluid is circulated through the cooler.

 

When you do your trans, if you do your trans, make sure your trans guy modifies the valve body so it will circulate in park. I'm sure every modded trans out there has this feature. Mine does.

 

The 999 (32rh) in my Jeep is the same way. The 46re in my 01 Dodge 360 was the same too. Fluid does not circulate in Park. Always good to circulate and warm up the fluid in Neutral while you're waiting for oil pressure to build. Hadn't thought about the cool down aspect, but that may be worth doing as well. Especially after a long haul. While you're idling your egt's down, let the tranny do the same. Can't hurt.

 

Back when it was 39 degrees in SoCal a few months ago.........I thought I would be smart and run High Idle for 3 minutes while I went back in the house to get something (I may have idled for 5 minutes in the driveway in park pointed down hill before that). Guess what? The red light came on to say the trans oil temp was excessive. Hmmm. Upon rereading the part in the manual that says to place in neutral when at idle for long periods. I do that now after start up.
Hasn't happened again, but then I don't usually idle that long. It is the ROC, can't pollute.

 

The transmission fluid circ schematics are in the owner's manual. It shows no fluid pressure to the torque convertor in park.

If your convertor has drained overnight and you're idling for a while with little fluid in it, that's not good.

When starting up, put the truck in Neutral, set the parking brake, set high idle, and enjoy the wait.

My trans builder said it is not advisable to modify the valve body for fluid circ in Park. I forget why, but you can ask him yourself. timinva is is user name.

 

The company I used to work for, cooked 2 dodge transmissions (one was a half ton 4x4, the other a 1 ton with the v10) in Indiana letting them idle on the highway in summer while we worked. After the new trannys were put in, they were told to use neutral to idle...

 

hey guys thanks for the replies, you never know if someone is blowing smoke up your as. Its a good thing to know.