Gear compatability ??

[MJRemi]

I have never dealt with 4x4 until now, so sorry about what might be a silly question. The Silver 88 front diff says 3:55 but has a D35 in the rear. I want to put my D44 3:54 from the Black 88. Does the gearing have to be exact or is this considered "the same" ratio?

I probably will not use 4x4 mode very often but when I do, I don't want to cause damage if the gears don't match.

[tbrand]

3.54 and 3.55 are essentially the same ratio - you won't have any issues.

[banshee]

:agree:

but extended time on road in 4wheel could cause issues with the drivetrain over time

‘shouldn't be an instant thing’...

Be careful and remember it’s there while in use on-road... B…

[Jeep Driver]

I've got 4.10 in front and 4.11 in rear, no issues.

[Geonovast]

Most of the gearing "differences" comes from people rounding differently.

 

Dana 35 "3.55" gear tooth count is 39 on the ring, 11 on the pinion. 39/11 = 3.545454545454.....

Some round up to 3.55, some round down to 3.54. AFAIK, the Dana 30(HP & LP), D35, and 8.25 all have the same tooth counts for 3.55.

 

Most 4.10 and 4.11 difference I don't understand, since most of our Jeep axles are 41 ring / 10 pinion. 41/10 = 4.10 exactly, so no rounding. The D44 however is actually different, at 45/11 = 4.090909 and 46/13 = 3.53846.

 

http://www.drivetrain.com/parts_catalog ... inion.html

[mvusse]

The difference between 3.54 and 3.55 is smaller than the difference between some of your tires due to air pressure fluctuations and tread wear. We are talking about a difference less than 1/5 of a percent (0.01976).

 

Assuming all your tires are exactly the same, on a straight road in 4wd, for every mile the front wheels travel, the rears will try to travel travel about 10 feet less. That's 10 feet difference over a MILE.

 

For all practical purposes they are the same, and are what came from the factory with a 4.0 4wd automatic and D44 rear axle (heavy duty rear axle, towing package, big ton/metric tonne package...).