Axle Strength

[overtimeracing]

Hey Guys. My son and I are building up a 87 trazer for him to harass the neighbors with when he is home from the Marines. How much motor can a set of stock 1/2 ton axles handle, and what kind of gear ratio am i looking for to make this truck feel like a muscle car with 35" tires. Im guessing 4:56 or 4:88's? Thanks for the help. Kevin

[pwradder]

front axle should be okay, depending how its driven off road-if its beaten like a rented mule its time to go with 3/4 ton stuff. as for the rear-do you have a 10 or 12 bolt? you should be okay if you have a 12 bolt. as for the gears, if you have no overdrive i'd go with 411's if any type of highway driving is done. i have 456's with 35's on my 77 k30 with a 3 speed auto-3000 rpm @ 65 mph! hope this helps.

[overtimeracing]

pwradder... Thanks for the reply. Yes it currently has a 12 bolt rear. And an overdrive tranny, however we will probably be upgrading the entire drive train to the toughest we can find. We used what we had to get the truck going, so he could drive it before boot camp. Now that it's going, we are going back through it to upgrade. We are looking at axle ideas, and gear changes first, to get a better seat of the pants feel. We had found a set of military 1/2 tons with 4:56 or 4:88 the guy wasnt quite sure, and was wondering if they would hold up to a 500 hp small block, we are planning in the future, followed by the appropriate tranny / TC. Im guessing another overdrive tranny and a 205tc? Thanks again...Kevin

[Rubble]

As far as the front axle,if your gonna be in any kind of mud you might be pushing it with a 1/2 ton axle on 35 s.There is no difference between a 1/2 & 3/4 ton front diff except rotors,I have swapped a few around and all I changed was the rotors.Your axleshafts or u-joints probably be the weak link.Don't ask how I know this...A Dana 60 in front would probably work,go with a 14 bolt full floater in the rear.I have a 86 K20 on 35s,350/465 14 bolt full floater 4:10 ratio.Runs about 26-2700 rpm @ 100 km/62 mph. Good luck...
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[pwradder]

i agree, 500 hp is too much for 35's with 1/2 tons. d60 front and 14 bolt ff rear should do the job just fine. the tough part is the transmission because a 700r is going to have to be built really well to take that kind of power (expensive)! i never had any kind of good luck with those trannys behind any thing that made decent power. so now to have od you'd be looking at a 4l80 those arent cheap either-plus you'd need a stand alone controller because they're electronic. you could swap to a stick- not sure what kind of power the nv4500's take. if it were mine and i was building a hardcore wheeler that didnt have to be a daily driver i would go with a 400 trans, np 205 case,d60 front, 14 bolt ff rear and 456's. 500hp would feel nice with that setup!

[overtimeracing]

Thanks pwradder... I dont think the od was an absolute necessity. We just thought the od would take some of the sting out of the 4:56/4:88 gears if he drives above 55-60mph. It will be a toy for him and not a daily driver except to show off every now and then, but yes it will be a heavily hammered mud truck first. TH400 sounds like the way to go, and we'll start looking for some one ton axles.

[overtimeracing]

Hey guys...Whats the best way to identify the d60 front axle? What should i look for? Are there any better years than others? Thanks again for all the help. Kevin

[overtimeracing]

And Thank You as well Rubble...

[Rubble]

Dana 60 was found in GM 1 tons,say from at least 1980 - 1989? If you can find one out of these models they will bolt right in to your truck.I think Ford & dodge used them as well but not sure what years.Far as identifying a 60, they have king pins verses ball joints.There is a cap over the king pins that make them fairly easy to pick out,if I was better with pictures,I could scan my GM service manual to show you what I am talking about.The physical size of a 60 is quite a bit larger than regular 1/2-3/4 ton front diff.
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[pwradder]

never heard of one year d60 better then another-not an expert on them though.also i believe gm started using them as far back as 1973, another easy way to identify them is the fact that the diff is so big they couldnt fit a fourth u-bolt on them! good luck with you're search-shop around a lot, some people ask crazy money for 'em.

[overtimeracing]

Thanks Guys...

[Mr. 250r]

Look for a 1991 suburban 3/4 ton 4wd parts truck, as it will have a fuel injected 350, a 4l80e *slightly lower first than th400*, np241 *lower gearing than 205* and plenty strong enough unless your are literally smashing it down on to rocks it will be fine, a dana 60 is identified on the front by the D60 mark or the larger locking hubs, where the last u-bolt on the passenger side would be will be 2 bolts instead, big problem with D60's are the king pins they are very prone to the death wobble if you don't know what it is look it up although ball joint front ends do this it's not nearly as bad as far as gearing since its not gonna be as much of a street truck i'd go with 4.56s or 4.88s then combined with the lower gearings of the 4l80/241 with 500hp first gear is gonna rip around just gotta worry about u-joints by then

[overtimeracing]

Mr. 250r... Thanks for the info...

[Mr. 250r]

Actually I forgot its where the 3rd u bolt would be on the inside of the passenger spring plate is two bolts not the outside its been awhile and the other plus side of the 4l80 is with such low gears the overdrive will make it street friendly

Few other things I learned while swapping in a D60 and FF is the D60 yoke matches the stock suburban 3/4 driveshaft u joints, if you want to go a little more modern and get a newer FF like I did from an 05 2500 it will have disc brakes and an regular e brake connection so you don't have to do a t case brake and it uses the big 1410 u joint which will handle 500hp although you'll need a driveshaft as they don't make a jump joint for that, but you'll need to move the spring perches which is pretty easy
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