so you it's okay to cruise 40mph with about 2,000 rpm in 3rd gear rather than 40 mph with 1,200 rpm in 4th lock-up?.... I don't think that will save diesel...

I want to be able to stay in 4th and cruise between 35-40mph... with the stock set-up it will not hold lock-up in 4th gear if you don't maintain 43-45mph... I want to be able to hold 4th at speeds less than 45mph.... like I said ealier.. I don't plan towing.. just city driving.. plus it can shave 3-5 seconds off 0-60 times!

 

Get a tuner, and have it custom tuned to hit lockup/4th gear at 40...... and hold it up to 30% throttle.

 

a tuner.. is on my list of mods for my new cummins.. among a dozen other things! I actually found the link I originally posted after I found a programmer that allowed you to set a speed for TC lock-up/ disengauge.. but they wanted like $350 and is hard to find.. i think TCS performance made it? not sure.. anyways that when I got the idea.. wouldn't it be awesome if you could shift an automatic like a manual? My 2012 F-550 at work has the option of either manual or automatic (pretty cool)... anyways.. a little research lead my to the link I originally posted... i figured for a free modification it would save me some fuel.. been paying between $3.99-$4.25 for #2. I know it could be hard on the TC, but only if you rally get on it and/or towing... I have 2 tranny coolers and an aux tranny filter... so I know my tranny would stay cool...and I'm driving like an old lady.. try to keep the rpm below 2000.. a lot more torque with my cummins than my old 360....I figured for light town driving it couldn't hurt that much.. has anyone tried this or am I going to be the first on DF? I'm also going to be installing a glowshift 3 in 1 guage pod to moniter boost, pyro and fuel pressure... looking into tuners as well... don't need anything speacial.. prolly going to go with superchips 3855 for now... don't plan on switching out turbo or injectors anytime soon... motor is bone stock minus the drop in K&N filter and 5 in muffler... stock down pipe though... it was installed by previous owner... sounds bas *** though! holy crap this is long... I need to stop drinking...

 

You can do what you want, but the info I get from my gauge, my tranny temp is higher driving around town with OD on.

 

I'm sure you are correct. The truck is new to me and still trying to get to know the driving habits of the new cummins... just seems to rev high for a diesel driving with o/d off... I will prolly do the mod this weekend.. see how it works... I could just disconnect the switch and put the relay back in if I don't like it. The person that sold me the truck put a lot of time into the tranny. I has the stock tranny cooler.. then an aux tranny filter and additional cooler.

a tuner is my next purchase after my guage set

 

Just completed this mod... took it for a test drive and all I can say is wow!

it's such an easy mod... gives you the ability to hold just about any gear at any rpm.... takes all of 10 minutes to do this mod... be careful because it will stall out if you do not disengauge it while coming to a stop.

made a huge difference in acceleration... shifts much like a manual... you can use the o/d button to limit the tranny from shifting in to over drive...

around town I was able to travel at 35mph in over drive while holding 950rpm... 40mph was about 1,000 rpm... let me know if anyone wants pictures... might do a DIY...

 

Might do a DIY? Come on man Really

 

DIY.. see link on first post!

 

I'm guessing this doesn't work on our 46RE's? Or does it?

 

Sure does.