410 gears in an 04 D2

rovercanus

Well-known member
Apr 24, 2004
9,643
244
I ran 4:13 gers on my 2000 4.0 for years. Don't know what the big deal is.
The 2000 is off the road now so I will swap the diffs into my 04. Both trucks are running 33's.
 

K-rover

Well-known member
Jan 15, 2010
2,163
62
Raleigh, NC
I haven't swapped in the 4.10 yet. But I have swapped the tires to 32. Honestly it wasn't that dramatic of a difference. I read some threads that made it sound like 33's were certain death to a stock truck. Or course I haven't done any hard wheeling with them either. Yet.

Shit I ran 32's on stock gears for several years.. Its not that bad at all... Currently 34's and stock gears suck ass!!
 

CORover

Well-known member
Jun 11, 2007
745
65
Colorado, USA
Shit I ran 32's on stock gears for several years.. Its not that bad at all... Currently 34's and stock gears suck ass!!

I am at 32, just a little under, with stock gears now. The only time it is bad is going up a steep hill, I could use more out of it.
 

Howski

Well-known member
Oct 19, 2009
1,483
209
Alabama
I haven't swapped in the 4.10 yet. But I have swapped the tires to 32. Honestly it wasn't that dramatic of a difference. I read some threads that made it sound like 33's were certain death to a stock truck. Or course I haven't done any hard wheeling with them either. Yet.

They're not. I ran a Detroit/TT combo on stock axles with 33's with no breakages. Just have to be a more cautious with wheel spin or any bouncing
 

Shiftonthefly1

Well-known member
Aug 11, 2014
433
14
Las Vegas
:banghead:
This is really simple, folks.
1) Go here http://www.ashcroft-transmissions.co.uk/calc/ratio_calc.html
2) Run the numbers for your stock truck with stock tires and gears. That is your baseline.
3) Now, change the diff gear ratio and tire diameter in the calculator to determine the best gearing option for the size tire you want to run.

According to some that's not true sir. That math LIES

But seriously I meant to say I swapped for 33's. I went back to Discount Tire and told them I wasn't happy with the size. So I went from 275/65/18 to 275/70/18. All free of charge. Gotta love that. I went from a 32 to a 33. The stock gearing kinda sucks a little at this point. But it's livable. The plan is to swap in the diffs and see how I like it. According to the calculator it won't be bad at all. If it sucks I'll pull them apart and change the gears down to 3.90. Sell the 4.10.
 

Blue

Well-known member
Mar 26, 2004
10,043
856
AZ
I checked my engine speeds against actual ground speed on a recent trip, photos are attached.

With my stock 2004 D2 gears and 285/75/16 tires, the following applies (give or take a few percent error):
60 mph = 2,000 rpm
70 mph = 2,300 rpm
80 mph = 2,700 rpm
90 mph = 3,000 rpm

This was fully loaded with camping gear, tools, wood, steel bumpers front & rear, winch, steel sliders, skid plates, etc. My truck feels plenty peppy around town and it climbs hills fine. On very steep, long inclines it may bog down in 3rd gear to about 65 mph but nothing as bad as my old '96 D1. It's certainly not a sports car but it is what it is. I've never longed for shorter gears. Note that my speedometer reads about 10% low.
 

Blue

Well-known member
Mar 26, 2004
10,043
856
AZ
Photos of 80 & 90 attached. I brushed 100 but didn't feel like messing with the camera!
 

bri

Well-known member
Apr 20, 2004
6,178
152
US
I have 235/85 and 4.10 on '98 D1., these are 32". Runs higher RPM, but in the hills around here not so much of a problem. Speedo seems about 20% off. Don't notice that much difference in gas mileage, but that does not really bother me.

I have a bigger problem with whining gears.

Years ago I ran D1 with 235/85R16 and 255/85R16 and stock gears. 235 frustrating in mountains. 255 VERY frustrating in mountains at speed. Off road, not much engine breaking going down and slightly under powered going up.

I am confident that I will like they better on and off road, with the exception of whine.
 

Frank4

Well-known member
Jul 10, 2012
61
1
Memphis
I have 235/85 and 4.10 on '98 D1., these are 32". Runs higher RPM, but in the hills around here not so much of a problem. Speedo seems about 20% off. Don't notice that much difference in gas mileage, but that does not really bother me.

I have a bigger problem with whining gears.

Years ago I ran D1 with 235/85R16 and 255/85R16 and stock gears. 235 frustrating in mountains. 255 VERY frustrating in mountains at speed. Off road, not much engine breaking going down and slightly under powered going up.

I am confident that I will like they better on and off road, with the exception of whine.

Can you give us any rpm/mph ranges?
 

Shiftonthefly1

Well-known member
Aug 11, 2014
433
14
Las Vegas
Um, your calculator that you posted says it a little over 1900 rpms @ 50 mph. So yes, yes you did.

Ashcrift did sir. Not me. But yes it does sound about right...in fourth gear...in OVERDRIVE. But I guess you know more than Ashccroft does on the subject. Thanks for the wisdom!!
 

SCSL

Well-known member
Apr 27, 2005
4,144
152
Years ago I ran D1 with 235/85R16 and 255/85R16 and stock gears. 235 frustrating in mountains. 255 VERY frustrating in mountains at speed. Off road, not much engine breaking going down and slightly under powered going up.

I remember that truck! Many good times.

The gearing question always makes me laugh. I've run stock gears on 35s for 11 years. And on 33s several years before that. Granted, I'm a bit lighter. But only by 800 lbs. I'm finally going 4.1 as I go to 37s but wouldn't go any further. Remember: the further you go, the weaker you get. My advice, and it's worth what you paid for it, is for a rig that's both street and trail, make your compromises on the street performance. The lessons learned on the trail are more painful and expensive than the inconveniences faced the street.