ROBERTSUNRUS

Hi, I own a 2000 Lincoln Navigator 4X2 and tow a travel trailer with a GVWR of 6,300 lbs. My Lincoln is rated to tow 8,900 lbs. Today I have two questions.

(1.) I would like to replace my 3:73 gears with 4:10 gears for a little better towing, especially in the mountains. But Ford doesn't allow for changing the specs for speedometer correction. Has anyone on this forum done this and how did you do it? [9.75" ring gear]

(2.) Also for towing, I bought a set of McKesh mirrors; I thought that they would be better than the slip-ons that I have now. But I can't seem to make them fit and don't want to break any windows. Has anyone on this forum had success with McKesh mirrrors on a 2000 Navigator or Expedition?

KStromberg

Hi ROBERTSUNRUS and welcome

Expect your mediocre gas mileage to become a little less mediocre. Other than that, your goal is going to be quite attainable with the 4.10s. The engine/transmission has a greater torque advantage over the tow load with the lower 4.10:1 ratio... I.E., this converts to less required engine torque to do the same work load. I will suggest more strongly than anything though is to get the biggest cooler known to mankind. I find one cooler to fall under that category and that is a tru-cool 40,000gvw cooler. It has a 45,000 btu rating and will guaranteed keep your tranny cool even under these conditions.

Here is the link to it:

transmissioncoolers.us: Tru-Cool MAX transmission cooler with external thermal bypass

__________________
-1992 Ford F-150 (winter truck)
-1998 Lincoln Mark VIII LSC (fun car)13.591@101.72mph

Hamfisted

Sure ! Just pickup a Diablo Sport Predator programmer (U7153) and you can reprogram your computer for the 4:10 gears, as well as other adjustments to make your Navigator a better performer.

You can usually pick one up on Ebay for about $250.
DiabloSport Predator 99-02 Ford F150/Expedition U7153!: eBay Motors (item 250696624290 end time Sep-20-10 17:36:40 PDT)


- Mike

360ci

I concur, any good name brad programmer can change tire size to suit axle ratio to keep your speedo in check.

Going with the 4.10s is a good move. If you're running close to GCWR with your trailer I will suggest going a step further to 4.56 gears. You won't feel much of a difference with the 4.10s. However, when not towing you'll more than likely see better mileage around town up to about 45mph, otherwise top gear cruising speed will be about 4-500rpm higher, with 4.10s it'll only be 200-300rpm higher, which really isn't much of a difference.

If you find that the highway rpms are too much, you can always get taller tires, by an inch or inch and a half to negate the higher rpms that the 4.56s will bring. Mileage will be less obviously on the highway when not towing, but around town you'll get excellent results. I also second adding a good cooler to use. Sticking with OEM tire height will of course give you maximum towing performance. I also recommend using a name brand synthetic axle fluid as well for even better cooling characteristics.

__________________
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!