With 37's even with 4.56's you probably won't be using the MDS unless you are going downhill with a back wind.

The programmer is still a good idea, as it will give you a slight gain in performance, but it will also allow you to adjust for the tire size and gearing in order to make your speedometer/odometer read correctly. Otherwise (as I am sure you have already noticed) your speedo will read quite a bit slower than you are actually going.

 

Ah ten four MDS gone... ha ha ha oh well... so thanks for the info... so if i get the programer im sure it has an application for plugging in my Gear ratio... also im prob going to get new differential covers and i know the rear is 12-bolt 9.25" but wut the heck is the front?? 12-Bolt 8.25"??? im not sure.... oh and looks like i'm going to go to 4wheel parts for the gears. G-2 4.56's front and rear gears.. Sweet deal 1336.00 total with install and gear install kit.. 25% off helps when u buy it online saved 450 on install.... oh and as for the CV joints long story short i already have new ones... and upper control arms... and ball joints... let just say the guy who installed my lift had to look at the instrutions to put the lift on and oh was banging my ex GF too!! ha haha got screwed both ways!! all is good now tho...

 

Yep, this venture is costing you quite a bit i see.....

 

ha ha ha like i said wouldnt of been if i didnt try and be the nice guy and help a friend out with his small mechanic shop..... should of just went to 4 wheelparts and got everything done by them... now i know... and knowing it half the battle..... GI JJJJJJOOOOOEEEEEE!!!!

 

For a gear install, you don't need to recalibrate the speedo or anything, so a programmer is not necessary in that regard. BUT you really need the speedo recalibrated for the tire size change and the other benefits one offers you. Getting one that will allow you to re-program the transmission shift points would be a huge plus (Superchips), although the gears will go a LONG way in helping out the transmission by getting the RPMs up into the engine's powerband and stopping the tranny from having to constantly "search" for the right gear.

4 Wheel Parts can be hit and miss. They WILL offer you about the widest range in gear and LSD options AND will price match IF you make them. But they tend to pay their techs at the lower end of the scale, so getting a good tech is iffy...

 

Do you say this because you can take the truck to the dealership and have the computer flashed to account for the lower gearing? OR does the speedo's on our trucks work differently than any other vehicle that I have owned? Usually adjusting for gearing comprises of a new speedo gear (cable driven) or an adjustment with the programmer to calculate the new speed of the wheels in relation to the revolutions of the drive shaft (computer controlled).

I am unfamiliar with how our speedo's on these trucks work, could you please school me Hammer.

 

Speedo is read off the ring gear. Unlike vehicles with the speed sensor on the transmission output shaft, gear ratio change does not effect the speedo BUT tire diameter does. Only a change in tire size will effect the speedometer...

 

Hmmm...Thanks for the info Hammer! I did not know that...I know my Mustang has the speedo on the trans, and my old truck had the speedo on the diff...

 

Thanks Hammer, I didn't know that. All of my past vehicles the speedo has read from the tranny. Appreciate the correction and info.

 

Well got my programmer and i fiddle with my truck a bit and well i shut the MDS off and are running the 87 octane tune.... got 4mpg back on the high way and speedo is back to normal.... i highly advise to anyone who has tires my size to shut there MDS off.. totally feel the difference... oh.... well i wanted to try the 91 octane tune or on my programmer is says preformance tune and i cant seem to find that gas anywhere... wut the heck??? does superchips have a 93 octane tune?? i didnt see it when i updated my programmer.... and also when i get my gears it has a setting for Axle ratio.... wut would i set that two if i get 4.56 gears and how do i figure it out??? sry again new to all this but every bit helps.... thanks again