I've slowly been buying parts for my '01 but never seem to have the time to do the install. I work in AK during the summer and run a commercial fishing boat but had to return after just two weeks due to some health issues my wife was having. Since I was now home (first summer in 19yrs and boy is it HOT in Chico CA during the summer, 108 +/- often), I figured I'd take the time do get some parts replaced, starting with some 3.73 gears. 

 

My buddy who is a former GM tech was in between jobs so I hired him to help with gear  set install. Well, the Motive D70 3.73 gear set did NOT fit my trucks carrier as we could hardly get a pattern in the paint as the ring gear and pinion were so far apart. We kept adding pinion shims and ended up with the end of the pinion about half way buried in the pinion nut, not good! I checked online and a few places had some Spicer gear sets on sale for 68.00!!!! These were D70 sets with 5/8" offset which is what is needed in Dodge D70 ( don't buy the standard set like some shops will tell you that you need). I paid an extra 30.00 for two day shipping and ended up with the gears a full 7 days later. Just Differentials screwed the pooch on that purchase! 

 

While I waited the 7 days for the gears to arrive (and missed a camping trip with friends since I had no truck to drive), I started installing the numerous parts I had piled up. I added a catch can under the front cross member and used a heater hose repair kit to attach the new section of hose to the factory original hose. I've only got 80k on my truck with no blow by so I think this single can will suffice with no gasket issues as some guys have seen. 

 

I had also purchased 17" rims a year or two ago in anticipation of upgrading the brakes to 3rd Gen units. I got those swapped out at all four corners and replaced the ball joints for good measure. Wow, drilling those ball joints is a pain in the a$$! I couldn't get the lowers drilled out so opted to order new Moog units from Rock Auto and hey, I was waiting on the gear set so had PLENTY of time! I added Monroe Reflex shocks and some coil spring spacers. 

 

The spacer kit for the 2wd is a Daystar unit. It just has two plastic spacers that go on the top of your coil spring. Since you have the steering knuckle off due to the ball joint/control arm replacement, its easy to pull the springs and add the spacer. You do NOT need a compression tool to do this, at least on the 2 wd vehicle. My rig has the factory tow and camper package along with Firestone air bags and the front of the truck sat way too low for my liking. Before the install I measured 34" to the bottom of the plastic wheel well trim and after installing the 1 1/2" spacers I now measure 37"! What the heck?????? I suppose they will settle down a bit but 3" out of a 1 1/2" spacer seems odd. The ride with the spacers seems no different than before. 

 

I also removed the factory trans cooler and hard lines. I went with a Tru Cool 40k unit and mounted it across the front of the cooling stack. I'd have liked to have seen it in place where the old cooler was but its just too big to fit there without interference. I bought hose and fittings from the local hyd shop and the total cost on those items were right at 110.00. I can't comment on cooling difference from old cooler to new as I also relocated my temp sensor from the trans output line to the port in my Derale deep pan. 

 

I have 32" tires and wanted to gain back some of the gearing loss due to the taller tires. I realize going from 3.55 to 3.73 is not much difference but I can run 32-33" tires and keep near stock gear ratio. I see a 125rpm increase at 70mph, going from 1900 rpm to 2025 +/-. 

 

I have a PacBrake unit that I've been fighting a leak on for about a year now so my next task is to find the dang leak so my compressor is not constantly running (I remove the fuse for normal around town driving to keep the thing from cycling on/off constantly). 

The final ratio of 3.73 is best. Like myself, I've dropped to 245/75 R16 tires (30.5 inch) compared to 265/75 R16 tires (31.6 Inch) which are one inch shorter but brought my final ratio from 3.55 to 3.69 which is just 1 inch of tire did this. Now my cruise state at 66 MPH nets me 2,000 RPMs which is the middle of the torque curve and allows me to reach the cruise state of the Quadzilla easily. That is where I'm getting my high MPGs between the cruise RPM, 24.5-degree timing, and my modified injectors which are popped 10 bar high but that retards the timing roughly 2 degrees but made that up on the Quadzilla now I've got clean fine mist for injection events. Now remember for every 1 pound of rotation mass you ditch is like 8 pounds off the frame. This is another reason I won't upgrade to 3rd Gen brakes because you are adding rotational mass to the axles. Then which oversized tires also adds weight to the axles. Then if your adding the 2 inch leveling kit you just ditch the natural rake of the front end and now adding more wind drag.

I added an inline on/off switch with led light to my Pac Brake for more control.  I didn't like the compressor coming on every time the ignition switch was turned on and also don't need the e-brake running around on city streets going red light to red light.