Hello all! I'm currently debating/planning on regearing the D2. I want to improve its on-road performance as I've started driving more on road miles compared to off-road miles. I originally thought I had stock 3.54 gears but supposedly have 4.14 gears. Which does align with the speed and rpm I see on the highway according to Ashcrofts ratio calculator. The goal is to get the rpms down while on the highway, and ideally increase top speed. I'm confused on what I should do to accomplish this? Do I re-gear to a lower ratio at the diff? ie 3.54? I'm still planning on cracking open the diffs and installing lockers so I'm still open to changing the gears out. New ring and pinion gears don't seem super expensive and if it means I can save on fuel, I would go for it.

Current setup :

• 33 inch tires on a 16 inch rim
• 4.14 ratio on the diffs (allegedly, I originally thought I had stock 3.54 gears but supposedly the previous owner put in 4.14)
• limited slip diffs front and rear
• Factory center selectable differential locker

Limitations:

• I drive slower as a result of the lower gears. I don't like seeing the RPM higher than 2,200-2,400. This usually adds a few minutes to a short drive, and hours on a longer drive. I used to be okay with it but I'm now driving further distances its become a nuisance.
• The limited slip diffs and the center locker only allows me the option of either completely unlocked or mostly locked. This has made a few obstacles tricky as the truck wants to shift or not turn the way I want it to. From my understanding (please correct me if I'm wrong), the front diff wants to lock up because of the difference in wheel spin and from the 50% torque split?
• To get to the main road from where I live theres a sharp left turn onto a busy road 35mph road. This means I often have to turn and accelerate at the same time. If I accelerate hard while turning left I feel the front lock up and pull me towards the left. It is manageable but not exactly fun. I am the sole driver of the vehicle for now, but worry if someone else drives it they could loose control.

Goal:

• Higher highway speeds. Currently I cruise at 55-60mph on the dash at 2,300rpm. I don't like how high the rpms are.
• Fuel economy increases, Hoping this will have some tangible effects on fuel economy.
• Better off-road performance, especially with turning and climbing rocks.
• Account for potentially switching to 35's in the future.

Questions:

• Should I attempt to install the gears into the housing myself? I've heard its complex but not impossible. I only have hand tools (ie no vice or special tools). I'm not against investing in new tools but not sure if I would be saving money by doing it myself.
• Any recommendations for air/electronic lockers? I would prefer selectable as I already have front and rear limited slips.
• Is it better just to save up for 35's and install 35s to get the rpms down? I may eventually move up to 35's but I'm worried about further hindering on road characteristics
• Anything I should be-careful of or things to look for? Any tips or tricks would be much appreciated.

I've been playing around with the ratio calculator on Ashcrofts website (https://ashcroft-transmissions.co.uk/ratio-calculator/) to see what the changes would look like I entered:


I only changed the diff ratio to either 3.54 or 4.14.

Left table is stock 3.54 gears. Right is my current 4.14 gears.

 

I'd go Ashcroft air lockers given the choice every time. Do the arb high output single compressor and if you don't have SAI it will fit nicely in the engine bay on the back pass side and can inflate 33/35s just fine. 4.11/4.14 is overkill on 33s in my experience. I have 4.11s on my classic on 35s and that is a dog haha but the truck will cruise on highway if it's flat just fine (CO elevation kills these trucks). I put a 1.4 t-case in my disco running 33s and it's about perfect with stock gears imo. The LT230 is great in that you can change the high gears relatively easily and I believe they even sell a 1.3 gear set which with the 4.11s might be a nice little bump when you go up to 35s.

 

I unfortunately have SAI . I have a cheapo smittbilt air compressor that has similar performance to the dual ARB but 1/3 of the cost. Downside is its bigger and doesn't mount nicely. On my old D2 I mounted a cheap air compressor on the old compressor mount for rear air. I have a 2 gallon air tank mounted above the rear axle (where the rear sway bars usually are), but still trying to figure out placement of an air compressor. My cargo space area has been gutted by the previous owner. I can plug in in an air compressor to the system for testing and maybe even for lockers if 2 gallons of 120psi air can last me a few hours out on the trail.

 

I don't think your rpms are that high. At 55mph im at 2k and I usually cruise between 65-75 for long periods which ends up being 2.5k-2.8k rpm. Everything is stock. Higher rpm makes my ticking noise go away, and I don't think its bad unless you're stuck in 3rd gear and crusing at 4k RPM.