axle swap idea

[necessayrevil]

The 9in in my 86 bronco needs a new pinion seal and the d44 need rebuilt(badly), and we have an 85 f250 diesel with a ford 10.25 rear and d44hd front with 3.55 ratio at work, my boss is willing to sell me both axles for the price of scrap($150 a ton). What am I getting myself in to with this?

 

[miesk5]

YO N,

I have some 10.25 installation LINKs in my site @ http://www.broncolinks.com/index.php?index=100

Including;

Installation in an 81

Source: by Ken S at http://kenshack.net/rear.htm

and the Dana44HD @ http://www.broncolinks.com/index.php?index=512

Esp by Keith (pics @ http://www.supermotors.net/registry/139/17344):

Excerpts; "...Here ya go, some TTB tech from the TTB hater. This is nothing new, except many may not understand the differences without pics

Q: I've discovered that many '80s F250s used 8 lug Dana 44 TTB (this is known as the Dana 44HD TTB). I can get a good deal on the setup and would like to swap it under my Bronco to match my 8 lug rear. Will it work?

A: No, it won't work, at least not easily. The beams are different lengths

http://www.supermotors.org/getfile/172405/fullsize/TTB8Lug%20002.jpg

In the pic above the shorter beam is from a D44 TTB HD. You could conceivably get the pivot brackets too (they're 100% bolted on on the D44HD) and transfer them to your xmember, but how much travel do you think that short beam has available?

Of course the shorter beam is not even good for shop art because there's less room to carve "= SOL" into it.

Q: Ok, then I'd like to just swap from the knuckles out using the 8 lug stuff. This way I should be able to bolt 8 lug outers onto my existing beams, right?

A: No, it's hard to see in the pic but the ball joint spacing is different by approx 1/2"

http://www.supermotors.org/getfile/172406/fullsize/TTB8Lug%20001.jpg

Also note you can't swap spindles out because 8 lug spindles use 8 studs while the 5 lug spindles use 6 studs (note spindle stud counts are not true for all D44's, just TTB D44's).

Bottom line, the best way to get 8 lug TTB is use Chevy outers as detailed by Dustball. Even better, start cutting up TTB, taking pics of it, and start building an engine stand w the beams..............er, at least that's what I did this weekend."

Also for both;

"...Ford built our Broncos & other 4x4 trucks & vans with a numerically lower front gear ratio in the front Dana 44 than the rear so that off-road steering is enhanced. A Bronco built with 3.55 rear ratio would have a 3.54 ration in the front Dana 44; or; 3.08 in the 8.8 & 3.07 in the Dana 44; or 4.11 in the 8.8 & 4.10 in the Dana 44, etc..."; Following was in my MS WORD Notes and the source, Randy's Ring & Pinion has removed it from their current web site; The gear ratio in the front of a four wheel drive has to be different from the front so the front wheels will pull more. There have been many different ratio combinations used in four-wheel drive vehicles, but not so that the front will pull more. Gear manufactures use different ratios for many different reasons. Some of those reasons are: strength, gear life, noise (or lack of it), geometric constraints, or simply because of the tooling they have available. I have seen Ford use a 3.50 ratio in the rear with a 3.54 in the front, or a 4.11 in the rear with a 4.09 in the front. As long as the front and rear ratios are within 1%, the vehicle works just fine on the road, and can even be as different as 2% for off-road use with no side effects. point difference in ratio is equal to 1%. To find the percentage difference in ratios it is necessary to divide, not subtract. In order to find the difference, divide one ratio by the other and look at the numbers to the right of the decimal point to see how far they vary from 1.00. For example: 3.54 ÷ 3.50 = 1.01, or 1%, not 4% different. And likewise 4.11 ÷ 4.09 = 1.005, or only a 1/2% difference. These differences are about the same as a 1/3" variation in front to rear tire height, which probably happens more often than we realize. A difference in the ratio will damage the transfer case. Any extreme difference in front and rear ratios or front and rear tire height will put undue force on the drive train. However, any difference will put strain on all parts of the drivetrain. The forces generated from the difference have to travel through the axle assemblies and the driveshafts to get to the transfer case. These excessive forces can just as easily break a front u-joint or rear spider gear as well

 

[Elmo]

I cant say for sure (please someone correct me if i am wrong) but i wouldnt think that the bronco and F250 would be very different in reguards to the frame. So if I am thinking right, you should be able to pull ALL the parts related to the suspension and steering, I mean ALL parts, like the coil towers if coil sprung,or front leaf springs and frame brackets, steering linkage, pitman arm, driveshafts, rear springs and brackets, TTB and TTB to crossmember brackets and rear diff ofcourse. Then put it all on the Bronco using grade 8 hardware and new bushings all the way. May be easier to just buy the whole truck for scrap price and scrap what you dont need. Sounds like it should work to me. Probably looking at two or three days work for you and two or three good helpers. Dont forget to take lots and lots of pics before during and after of each vehicle. For your referencing how and where things went and for our viewing pleasure.