What issues am I going to encounter if I decide to swap out my front axle on my 87 V10 (1/2) truck?

I currently have the standard 6 lug GM 10 bolt 8.5 inch front end.  I have access to a 6 lug Dana 44 from a mid-late 70's GM truck.

I was told the Dana 44 should bolt right up but I do not know about making the connection with the driveshaft and whether the length is same.  Also the hubs are on Dana 44 are the old full time hubs while mine are the standard lockouts.

My truck has the NP 208 transfer case and I am not sure about the donor truck.  I assume it  must be a NP 203 or NP 205.

Both truck have auto transmissions, I have the 700R4 and the donor truck has either a TH350 or 400.

Depending on Dana 44 gear ratio, I may swap out the rear-end from the donor truck.  The donor truck has a GM 12 bolt (8.75in? ring gear) while my truck has the GM 10 bolt 8.5in rearend.   What issues will be encountered there? 

Any help will be greatly appreciated!

Measure from the center of the axel tube to the pinion yoke where the U-joint is on both axels. If it is the same you should be able to use your drive shaft's. Also check to make sure that the drive shaft u-joints are the same size.

Take a look at the steering lincage on both axels and make sure that they are the same.

Do some measuring on the front hubs. I have not done this swap but the outers may be interchangeable. The full time front hubs are not an issue as long as you don't use 4 wheel drive on hard surface roads. The front diff and drive line will be turning all of the time. You can also use any Dana 44 locking hub assemblies to replace yours later.

Yea, you may have to do some mods on the steering linkage. Does the donor truck have disc brakes or drum brakes ? The steering knuckles will be different for each. NP203 and full time hubs were common in those model trucks. The standard gears were also 3.07 ratio on these Dana 44's. You may also have to look at the gears on your truck to make sure they are compatible. Front & rear axle ratios have to be pretty much the same.

Most Dana 44's have a metal tag on the bottom of one of the 10 cover bolts that lists the ratio on the axle, unless someone changed gears on it. Then you have to count the gear teeth on ring & pinion gears to find your ratio with a formula.

The axle u-joint types, and existing axle length would be something to look into, as stated before. You may need to have the drive shaft shortened or lengthened as the case may be. Does your current truck have a front CV joint axle ? If not, I'd take the one from the donor truck, and have it modified. Make sure you get the shaft balanced before you use it after mods. Otherwise it could tear up your drive train components. CV joint axles are more forgiving on pinion angle mis-alignments.

- Just some ideas for you. Hope this helps you some.

I had to do the opposite on my truck replacing the broken dana 44 with a gm 10 bolt off a k5. Every thing went together perfecly except i had to change the universal. The steering bolted right together with no issues.  

Thank you for your input.  I am getting the driveshafts also.  I guess my next question would be....is it worth the effort?  I am getting the D44 front, 12 bolt rear and both driveshafts for $100.  I like to mud and play offroad.  I run in a local mud bog once a year.  Another competitor gave me the idea to find a D44 front for much truck since it was significantly stronger.  He told me the swap was fairly simple.  So now I have been patiently searching to find a D44 w/ six lugs and as it turns out my brother in law had it all along.  The funny thing is... he has an old ford pickup sitting out in a field.  Just due to my nosey nature (when it comes to trucks) I was checking it out and realized it had six lugs?  So when I asked him about it...he said "yep, ford body on a chevy frame"  I crawled underneathe and scraped away the grime til I found the "44" stamped on the housing.

But...is the D44 overkill?  I have a stock TBI 350 with 33in knobbys and a relatively light foot. 

That would be a down-grade in my opinion ( Dana 44 to GM 10-bolt ), but whatever gets the truck running is better than nothing.

I'd go with a Dana 60 in front if money was available, but I'm the same financial boat most of us are in these days - times are pretty bleak. I'm still dreaming of my GM 14-bolt FF 6-lug rear axle conversion with a Detriot locker. I know I'll have to re-locate the spring-seats, and modify, or replace  the rear drive shaft on this mod from my current GM 12-bolt axle.

Two good axles, and two drive shafts for $100.00 to boot ?.

That's a good deal, dude! If your'e going in the mud the Dana-44 front and GM-12 bolt rear is not a bad combo. That's what I got in my '77 K5. Just get some good gears for it like 4.56's or 4.11's depending on the the driving you will be doing - mostly trails, off-road, and around town, oh highway driving at speed.  I'd consider an ARB Air Locker for the rear too. I know some old Fords had Dana 60 front ends, that would be better than the Dana-44 in my opinion There would probably a lot more mod work with the Dana 60. The GM 14-bolt FF rear axle axle is better than the 12-bolt too, but most are 8-lug, and you will have less ground clearance unless you grind down (shave) the bottom of the case like so many off-road folks do. 14-bolts are esaier to work on and cheaper on parts and re-gearing than other rear axles.

I've got pretty much your arrangement of engine and tire size on my trucks, and a Dana-44 would not be overkill at all.  Rockwell 2.5 ton military axles front & rear would definately be overkill.  I love overkill, in case you couldn't tell !  An NP-205 Doubler T-case would go nicely with my Rockwell axles too! ....and the 383 stroker engine, of course.

Hope this helps you some.

I've read a lot about what would be the ultimate set of axles and having air lockers and all that.  Right now what is really killing me is $$$$.  My old lady and kid seem to have a shop vac in my pocket and suck out every last coin and dollar bill I get.  The reason I would go with the D44 and 12 bolt is cause they available to me cheap.   I will purchase the axles and driveshafts but it might be a while before installation.  I just wanted to know how much of a headache I was getting myself into.

I do appreciate everyone's input.  It clues me in as to what to expect when I'm under the truck and it will give motivation to think "hey, this is a fun project that will definately make my truck better". (provided my head isn't up my rear and I put the D44 in the back and then wonder why the differential doesn't line up with the rear transfer case output)

I'm in the same financial boat you are, dude, I've been working on getting a used Corporate 14-bolt FF at a bone-yard somewhere, and just let it sit in the garage until I can accumulate all the parts I will need for my swap with the current 12-bolt rear. I've heard the junk yard 14-bolts can be had relatively cheap. The Detroits for the 14-bolts are the least expensive ones too, I've heard.

Just keep the gear ratios in mind when you swap your axles. A lot of folks overlook that one item with axle swaps. It don't work so hot when you got 4.56's in front. and 3.08 gears in the back - a lot of pinging  and popping noises that result in $$$$$$ needing to be applied to the problem.

You can't go wrong with the D-44 / GM 12 bolt combo you're planning. I'm just one of those 'overkill' guys that wants the best there is - within my financial spectrum. Good luck with your mods!

I went from a 10 bolt front and rear to a 44 14ff with no trouble at all had to make drive shaft for the rear hadto get a fancy u joint to fit 1/2t shaft 3/4t yoke big $$$ front bolted right up  

10 / 12 rear is not a big deal but 12 to 14ff needs another drive shaft as you said. That's another of the expenses holding me back. 14ff are easier to work on and cheaper in parts - including the Detoit locker option. You didn't have to relocate the spring seats to get the 14ff back there ?  

No it bolted right up. I did have to make the drive shaft shorter cut it in my garage with no noticable vib. not always cheaper just stroger so you don't have to repair it as offten