Sense I bought my '03 2500 I have always been very particular about driving with the over drive off when driving around town and back roads. I usually don't use the over drive until I hit about 50 miles and hour or so. I have noticed that the truck does seem to drive better in a higher rev around back roads and up and down hills. My question is am I saving the transmission by driving around with the over drive off around town and through the back country roads?

 

Nope.Maybe marginal but doudt it.Unless its really hunting leaving it drive is fine.

 

Ok, thanks for your input on the OD question I had. One more question? What is the general consensus of towing with or with out overdrive?

 

If you're towing heavy enough that you don't have much throttle response then drop out of OD and driveability improves. I don't use OD much if I'm on a winding mountain road for the same reason, even when empty. Every time I let off it shifts up then when I need a little power it has to decide what to do and then shift down, gets to be annoying. But, having said that, I really like the very tall gear of OD lockup and think it's great for straight stretches and mild hills. It let's the Cummins roar.

I'm going to put in a shift kit and a manual lockup switch soon. Those two things will really improve mountain driving.

Wetspirit

 

While towing, I generally lock out the O.D. on hills (up or down) if I'll be going under ~60 mph.

On the flat I just leave it alone, unless I want to avoid that nasty sounding turbo bark at 45mph when it drops into 4th under mild acceleration.

 

Yeah, agree with both of you. I always lock the over drive out going up or down hills at lower mph's towing heavy loads. I do like to feel and sound of the truck when the Cummins is working with the over drive locked out. I even drive alot with the over drive locked out with no loads just because I like the throttle response better. I have even been told that it does save the transmission by keeping it from shifting all the time. But who knows if this is true because I have never taken two transmissions apart to compare the difference with one driven around town with over drive locked out and one driven with over drive locked in all the time. Can anyone explain to me the manual lockup switch.

 

Just installed a lockup switch (04.5 w/ 48RE), seems to work just fine.

Here is the process in a nutshell (for an 04.5, should be the same for 04 and 05):

The objective of the lockup switch is to ground a circuit that controls a "lockup" solenoid in the transmission; thus, achieving control of the torque converter lockup. To achieve this you must tap into PIN #7 on the round 8-pin connector whic resides on the top drivers side of the transmission. The wire you tap into PIN #7 should go to ground through a 33 Ohm resistor (radio shack item) and obviously a switch or relay that you close when you want lockup (I used a realy and fused the circuit as well).

When you ground PIN #7 while in "D", "2", or "1" the torque converter will lock-up and direct drive is achieved.

If you'd like detailed instructions on how I did all this let me know and I'll post it. Just did mine yesterday, I like it.

 

eastmentCTD600,

Yeah, I'd like detailed instructions. Hope to do this mod soon, and you've been through it. Thanks,


Wetspirit

 

Me too as well, posted instructions would be greatly appreciated

 

eastmentCTD600

Would your guess be an 2003 w/ 48RE, wiring would be the same?

 

I beleive the wiring for the 2003 would be the same, I will attempt to verify when I get a chance. You can find the factory wiring digrams for our trucks at http://www.dodge.com/bodybuilder/index.html - this is where I got my wiring digrams for the mod. FYI - the Transmisson Solenoid Assembly that this modification "taps into" is the same for 1998+ dodge trucks (so the parts guy at Dishman Dodge says).

I will try to post a detailed procedure tomorrow and a pic or two of the switch/relay I used (it turned out pretty slick!), lately I've been working 12 hour days and haven't had time to report on the switch install... but I will get soemthing out there soon, hopefully with a wiring diagram and a schematic as well.

 

eastmentCTD600 / When ever you get a chance to post detailed procedure and a pic or two of the switch/relay is fine. I am in no hurry. I do have one
question for you, Will this mod decrease the life expectancy of the TC?