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Ranger (RBV) Axles FAQ ****Plead read here before posting!***

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Forum Moderator
Aug 19, 2001
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So. Calif (SFV)
Vehicle Year
Engine Size
2.9L, 4.0L
Before posting, please take a look at the following Frequently Asked Questions to see if your answer may already be here.

This section is for all questions regarding the Dana28, Dana35, 7.5" & 8.8" axles that came as factory equipment in all Rangers, Explorers, Bronco IIs, Mazda Navajos, and '94+ B-Series pickups (Ranger Based Vehicles). Questions about a Dana44, Dana60, Ford 9" or any others should go in the Non-Ranger axles section just below this one.

  • What axle(s) does my truck have?
    Please check these links

  • What gear ratio does my truck have?
    Check here:

  • Can I swap my automatic 4WD hubs for manual locking hubs?

    Hubs swaps are quite easy on many models.
    For '83-'97 Ranger, '84-'90 Bronco II, and '91-'94 Explorer & Navajo
    AVM manual hubs for '98-'00 Ranger models

    '01-'11 Rangers, and '95-'01 Explorers, not so easy. Due to the live-spindle hub setup (axle is permanently engaged), manual hubs cannot be fitted on these axles.
    However this page was written prior to the AVM manual locking hubs becoming available as one way to deal with the problematic PVH system on the '98-'00 models. The reverse of this conversion can be done on a '01-'11 model so that the AVM hubs can then be fitted.

  • Is my rear 8.8" axle 28 or 31 spline?
    Check the diameter of your axle tube next to where the leaf spring perch is welded:
    2.75" = 28 spline
    3.25" = 31 spline

    More info here: http://www.therangerstation.com/tech_library/Axles.html

  • Can I convert my 28 spline 8.8" to 31 spline shafts?
    Converting a 28 spline axle to 31 spline is only possible if you use custom aftermarket shafts made for the application (they can be ordered from places such as Moser, Currie, or Dutchmann). It is NOT possible to use Explorer shafts or Ranger FX4 shafts in a 28 spline housing, as the length is different (Explorer shaft), and the wheel bearing journal is a larger size (both).

  • What's the best gear ratio to have for "x" diameter tires?

    The following ratios have been optimized for both power & MPG:

    ALL RBV engines EXCEPT 4.0L V6:
    27" tires = 3.73
    29" tires = 4.10
    31" tires = 4.56
    33" tires = 4.88
    35" tires = 5.13

    4.0L V6 engine:
    27" tires = 3.55
    29" tires = 3.73
    31" tires = 4.10
    33" tires = 4.56
    35" tires = 4.88
    37" tires = 5.13

    For very early Rangers without overdrive transmission:
    Use 4.0L chart

  • Can I change gear ratios myself?
    You are looking at a potential huge can o' worms here...
    Gear setup is very intricate work dealing with very close tolerances. If you don't have all the proper specialized tools and knowledge, it is strongly recommended that a rearend shop do the work (the smallest mistake will more often than not result in catastrophic failure of the ring & pinion gears).
    Swapping of the axle as a whole unit can easily be done by your average home mechanic however. If the ratio you want can be found in an axle from a wrecking yard, this would be the easiest way to go.

    If you still want to try your luck on a gear swap, these links should provide a good start on getting to know the ins & outs of setting up gears:

    8.8" gear install:

    Gear setup tech:

    A site dedicated to what gear contact patterns should & shouldn't look like:

    Yukon Gear gear installation manual:

    One of our user's experiences with a 1st-time gear setup:

  • What is the biggest tire my stock axles can handle?
    Generally speaking, it is possible to use the following sizes without excessive risk of stuff breaking:

    Dana28 TTB = 30x9.50R15*
    Dana35 TTB = 35x12.50R15*
    Dana35 SLA-IFS = 33x12.50R15
    Ford 7.5" = 33x12.50R15
    Ford 8.8" 28 spline = 35x12.50R15
    Ford 8.8" 31 spline = 37x12.50R15

    *If your truck is fairly light up front (Bronco II, or 4-cylinder standard-cab Ranger), it should be possible to run 37X12.50s on the D35 (31x10.50s on the D28) as well.

    Driving style of course plays the biggest role in axle longevity. Abuse it hard enough and you can break a D35 (or even bigger) running P235/75R15 street tires. The above list assumes use with a locking differential, but that you don't go mashing the throttle every time you try to gain traction.

  • What upgrades are available to improve the strength & reliability of my axles with bigger tires?
    Lot's of good info here:

  • Whats the best traction-aiding differential (locker)? What's most popular? What's right for me?
    Check these links for some info dealing with this subject:
    http://www.therangerstation.com/Magazine/Feb 06/tech.htm (explains each type, and their behavior)
    http://www.therangerstation.com/tech_library/LockerComparo.html (has info on many specific examples)
    http://www.therangerstation.com/forums/showthread.php?t=4086 (what everyone here is running)

  • How easy is it to swap the D28 out for a D35?
    Check here:

  • How wide is the axle I have? (or, is "x" axle wider than "y" axle?)
    RBV axles have the following widths at the flanges:
    '83-'90 D28 front = 58"
    '90up D35 front = 59.5" (both TTB & SLA)
    '83-'92 Ranger rear axle = 56.5" (7.5 & 8.8)
    '93-'11 Ranger rear axle = 58.5" (7.5 & 8.8)
    Bronco II rear axle = 58"
    Explorer rear axle 59.5"

If your question was not addressed here, then please feel free to post it in the forum. Someone here will be glad to help. :icon_thumby:

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