Mismatched differentials

[Ram06_1500]

I have a 2006 ram 1500 SLT.
It’s a 5.7 4x4. My rear differential spider gears went so I had to do a rebuild. I checked the bin code onLine and it stated I had a rear 3.55 differential. I ordered a 3.55 rebuild kit and already completed the break in. Last night I thought id replace the front differential oil. On the cover it stated 3.92. I haven’t used the 4x4 during since the rear rebuild. As for the rear I know I should of counted the rings to confirm before rebuilding instead of relying on the vin. Will I have any trouble if using 4x4?

 

[pacofortacos]

IF you have 3.55 in the rear and 3.92 in the front.
IF you use 4WD things will go BANG, KAPOW, BOOM.

Quick test of the rear ratio, put rear end on jack stands with tires off of the ground, put trans in neutral engine off, mark the tires and driveshaft, and then count the driveshaft turns that it takes to make 1 complete tire revolution. Much easier than pulling the cover.
3.55 driveshaft turns to 1 tire revolution = 3.55 ratio, I think you can figure the 3.92 part

OR

Are you saying you put 3.55's in - not sure what a 3.55 rebuild kit is.

 

[Ram06_1500]

I installed a rebuild kit along with 3.55 Ring, piñon and installed a LS trutrac. Again, I should of just counted originally instead of relying on vin decoder.

 

[HemiLonestar]

Trouble? Naaaah, no trouble at all lol........

 

[Snake15eyes1998]

You need to put 3.92s back in or disable your 4x4 so you don't forget. But this is a disaster waiting to happen. Good luck man. Hope you get it sorted out.

 

[HemiLonestar]

 

[RoadRamblerNJ]

Welcome to the Knucklehead club. I would guess everyone in here has pulled something dopey at least once. I know I have. At least you asked before trying it. Nothing broken, nothing lost except your labor.
I bet the next gear swap back goes a lot faster! .

 

[Redtruck-VA]

I would count the front to confirm it is a 3:92... and if found to be a 3:92 then change the rear to match the front.

 

[Bob Macknight]

You could just contact any dodge dealereship and have them run your vin to confirm what your front diff was from factory

 

[Daniel57L]

2006 5.7 I almost did the same thing. I ordered the 3.92, because that's what my Vin called for. Pulled the diff apart and found out its 3.55. Waiting on the correct parts. FFS should have just looked at the front diff, its got the sticker still. Would have save 2 weeks