I have a 99D with the 360, neat rig, having custom long tube headers installed andthe cam's in.
I came across a set of R/T axles w/3.92's for real cheap on craigslist. Sweet, bought a T/A girdle for the rear axle installed it, sweet. Thought I would dress up the front diff, hmm, what is it?
Owning a SLT not R/T when I try to ask the dealer for information on this 12 bolt frontdiff they say that withoutmy vin#they don't know anything about the diff's type.
So, not knowing the exact year and vin# of the axle's donar I am at a loss as to identifying itand buying me a pretty alumium cover.
please assist

 

What was your previous rear axle? r/t's are the same with just a little extra flare (some awd transfercase, and gears) for drive train. Check the tag or numbers on the diff. Up to 99 fronts ran dana 35's 00 on ran Chrysler 7.625 if im not correct

 

My D was original with 3.55 gears
The R/T axle looks like the original, except for the cover, which has 12 bolts.
R/Ts front diff's tags say 0560 and 3.9

 

I think you might be confused. Im almost 99% sure your new/old diff should have 10 bolts. Then again i maybe wrong, take another look. Unless you did a sas lol.

 

99:

Depending on what year your SLT is, the front axle should physically be the same, but the gear as you know is a 3.92 which was standard on the RT package.

The rear axle is a different story. The part time 4x4 D's had the 9.25 12 bolt housing on which the inspection cover looks like a stop sign.

On the other hand, AWD D's got the 8.25 housing which only has 10 bolts. The RT rear end againhas the 3.92 gear as well as the Anti Spin (limited slip) carrier.

If you wanted to upgrade to the 3.92 gear on your D, this is a great way to do it as long as you have the tools, time, and muscle to do it.