3.92 Rear Axle Swap

[Rob Evans]

Good Morning Everyone,

I have a 2004 Ram 1500 4x4 with the 3.92 ratio. My son was driving the truck at the time and didn't realize that it was leaking from the rear seal and in time, heated up the housing and stripped the ring/pinion gear. I replaced the gears and seals, but there was a small amount of play due to the wear/heat of the prior gear and this has now ruined another set of gears. I am having a difficult time finding another 3.92 ratio axle in the area I live in, but can find the 3.55 it seems at all salvage lots.

Question is this. Can I run the 3.55 ratio in the rear and have the 3.92 in the front? Or can I buy a 3.55 axle and then get another set of 3.92 gears and swap out?

Thank you for your assistance,

Rob

 

[WilliamS]

If it was heated enough you may have warped something on the housing. If it were me and my truck, instead of throwing more gears at it Id buy a whole new rear axle.

 

[Rob Evans]

Thanks William, I think you are correct in that the housing is most likely warped to ruin the 2nd set of gears. Problem I'm having is locating another 3.92 axle and then the cost is almost twice of some of the others like the 3.55 ratio.

 

[Pull Ya]

You must run the same gear ratio in the front and back. Contact Matt at Moe's Performance(a preferred vendor on this site)about the availability of the gears and install kit for your truck. You can buy an axle housing with any gear ratio and change the gears to whatever ratio you want as long as you do both front and rear. If you ruined the second set of gears are you sure they were set up correctly---it's not a shade tree mechanic job. Setting up gears properly should be done by someone that is trained to do that type of work and has the proper tools to do the job.
Jay

 

[smithwessn]

As stated above, front and rear axle ratios must be the same or you will destroy the transfer case when its put in 4WD.

 

[Redtruck-VA]

If you believe the housing is warpped and want to replace it the 3:55 candidate is a good choice. The housing I'm using was originally a 3:55. Years ago I installed 4:10 gear with a DTT carrier. Now it has 3:92 gears. Personally I would carefully rebuild what you have and closely inspect the tooth pattern. It a proper pattern can't be achieved proving the axle is wrapped, then replace the housing...