SkyHarborCowboy

Since so many complain about the stock AMM rear axles of the lack of a Locker Unit, Replacement Gear Ratios and whatever else there is to complain about. I was wondering if anyone has converted their truck to a Dana 60, 70 or 80 rear axle. If so, I was wondering what was involved in the conversion. I am always hunting for 7th or 8th gear on my truck and it seems like the only option is either a Gear Vendors Overdrive (way too pricey) or the possibility of changing out the rear axle. That way you can get a Detroit Locker, get rid of the 3.73's and put in a higher ratio (not sure is actually available). I dont tow near max capacity I am in the 10,000# range so I dont think performance would suffer too much with something along the lines of 3.54's or possibly 3.31's in the rear axle.

Joe

djgaston

I don't know of anybody that has done that but the axle strength would be about the same. More than likely, you would need to redo the spring perches and possibly the shock mounts, as well as modify the end of the rear driveshaft. The AAM's use flanges, the previous Dana's use a regular U joint. Also, make sure you get an axle with rear discs, or put an aftermarket kit on... no sense in taking a step backwards and going back to drum brakes.
For gear ratios, I know you can definitely get 3.55's but I have not seen any lower than that. Can't you get 3.55's in the AAM axle? Yeah, I just checked their site, they offer 3.54's for the 1150 rear and 3.42's for the 1050 rear.
Basically, the 1150 rear is a Dana 80 and the 1050 rear is a Dana 70, FYI.

PourinDiesel

The 1150 is stronger than the dana 80 in stock form in my opinion.
Look at one side by side sometime.

4x4not

You'd have to adapt the tone ring in too for the ABS because it drives the speedo.

superman

I wish I could find the link but the 1150 is not stronger than the D-80...it is in fact the other way around. The 80 has a higher max torque rating and a higher continuous torque rating.

BUT comparing axles to axles the 1050 AAM is comparable to a D-70 and the 1150 is to a D-80 as far as size is concerned. And although the 80 is stronger I doubt you'd hit the max torque rating for the 1150 so it wouldn't be a worry. **** I wish I could find the numbers...maybe someone else will know.

PourinDiesel

Well I have seen alot more D80's pinions break sledpulling than 3rd gen 1150 pinions.
That in itself has alot to do with the strength of the unit.

As far as factory ratings go; what do they know?
Are they putting 1000ft lbs sledpulling through them?

superman

Well if you take into consideration how many D-80's are out there in comparison to the relatively short run thus far for the 1150 in our 3rd gens...it stands to reason you'd see more D-80's broekn...there's more of them. As for factory ratings...these should be numbers from the actual axle manufacturers...and I'd wager they DO know......

These are copied and pasted from a post on TDR by member rbattelle.........................But I doubt the continuous tq rating is as high as the max tq rating on the AAM as is stated below. ......................................

he January 2005 issue (isn't it only November?) of Four Wheeler has a nice table of strength ratings for some common axles. I didn't scan it as an image because I'm not entirely sure how copyrighting works and whether I'm allowed to scan a magazine image and post it here.

Anyway, the data for the axles we're interested in is (MOT is max output torque, COT is continuout output torque):

AAM 9.25 Front - 4663 ft-lb MOT (no COT given)
AAM/GM 10.5 FF Rear - 6242 ft-lb MOT (no COT given)
AAM/GM 11.5 FF Rear - 8321 ft-lb MOT (no COT given)
Dana 60 Front - 5550 ft-lb MOT (1500 COT)
Dana 70 HD Rear - 8800 ft-lb MOT (2000 COT)
Dana 80 Rear - 10000 ft-lb MOT (2500 COT)
Ford 10.25 FF Rear - 8300 MOT (2000 COT)
Ford 10.5 FF Rear - 10660 MOT (2900 COT)

There are some interesting things in this data. First of all, none of the AAM axles had a COT rating. I take that to mean that the COT and MOT for AAM axles is the same (they are rated for continuous maximum torque output). If that's true it would be VERY impressive given how much lower the COT ratings are for every other axle in the list. Second, the list indicates the AAM 11.5 inch rear is weaker than the Dana 80 and the Ford 10.5 inch rear. I had been operating under the assumption that the 11.5 was at least as strong as the Dana 80. Third, in the table in the magazine there's a little "+" next to the AAM 11.5 and 10.5 rear ends that, according to a footnote, indicates that higher-rated versions of these axles are available from the manufacturer. Perhaps we have higher rated versions on our trucks?

PourinDiesel

Superman,
The Dodge 11.5 AAM is not the same exact unit as the Chevy version.

As I remember tube thickness is larger and I think the axle shafts are larger in diameter.

Herrin811

AAM spec in metric

Dana doesnt list any specs


This is the kind of info I want to know....Exactly what is under my truck

DixieMfg

There's all kind of specs and comparisons in the forums on www.pirate4x4.com , look in the dodge discussion section, you should find some info....

realsquash

The ratings from the manufacturer have to be taken with a grain of salt. As you can see they aren't even rated in the same way. I would rank the AAM1150 higher than the D80 any day because of the extra pinion support. In reality either axle is probably going to be fine in a normal towing application.

Andy

staarma

I heard that AAM and DC are testing a 3.42 gear. Here is a quote from a guy on dieselram.com.

"Hi Folks,

A couple days ago, I sent an email to American Axle with regard to the concern about drive ratios in G56 equipped trucks. I asked them if they had a solution.

I received a reply today. According to them,,,

""Yes there is a lot of complaints about the high RPM and low mileage. DCX is looking at a lower ratio (3:42), but it is under testing now.""

It looks like they are aware of the problem, and are working on a solution for it. The fact that they are researching solutions so soon after the introduction of the G56 indicates, at least to me, that there has been a lot of negative feedback from owners.

Hopefully, those who purchase new trucks with manual trannies will soon have a choice. I will probably not retro mine, as I use my truck almost solely for heavy towing. It would be nice to have a choice, but it will be just one more agonizing decision to make when "spec'ing" out a truck."

http://dieselram.com/cgi-bin/ultimat...;f=29;t=005218

Patrick Campbell

You can convert NM and KG to LB FT and LB pretty easily.

There is a chart at the bottom of my page:
http://xj.cdevco.net/auto/dodgetowing/

axle gross axle weight rating axle torque capacity
aam 10.5" (2500 so automatics) 10020 lbs. 6231 lb. ft.
aam 11.5" (ho's and so 5-spd's) 10912 lbs. 8333 lb. ft.
aam 9.25" (front differential) 5511 lbs. 4646 lb. ft.

Going from an AAM to a Dana is a lot of work. Why don't you put a 3.55 gear in the AAM?

BTW Dana has specs you have to dig, dig and then dig some more. Of course once I found it, I copied it.
http://xj.cdevco.net/auto/pdfs/dana_axle_ratings.pdf

EDIT: I will throw up a chart comparing the Danas to the AAMs in HTML...

2broke2smoke

regardless of the stats i'd bet that if you are beating on a 80 or a 11.5 hard enough to break one than you would break the other ...

they are both good axles

lmills

Justin, that's because us lowly 3rd genners don't make enough power to break them.