Alluminum Driveshaft Question

[valentini]

Hello everyone,

I have recently built a 1972 GMC pickup and lowered it with Air Ride Suspension. My current issue revolves around the driveshaft length. It measures 73.5" and needs to be constructed of aluminum. Can anyone give me information regarding you experience with this type of setup? Also I am trying to locate a reputable shop in Colorado that can build this for me cost effectively. Any help is appreciated.

Thank you,

[71chevylowrider]

I have an aluminum driveshaft in my truck, I abuse it all the time, (that reminds me I need new back tires) I don't know much about them though, it was in my truck when i bought it.

[valentini]

Do you know how long you driveshaft is? Do you have some more pics of your truck?

[71chevylowrider]

I do have some pic's from under the truck that shows the drive shaft, but their on my home comouter, I can post them later when iget home for you, oh wait, maybe I can find them here, I posted them once before, I don't know the length, but I can measure it for you when I get home if that helps.

[71chevylowrider]

Here's my aluminum shaft, let me know what other pic's/measurements you might need.

[71chevylowrider]

My truck is pretty low too if that helps.

[valentini]

This is a shortbed correct? I am guessing it is a bit shorter than mine. however, if you can measure it I would appreciate it. If you do, can you measure from the end of the transmission or the seal to the center of the u-joint that connects to the rear end. I would appreciate it.

Off the subject how wide of a wheel were you able to get on the back of your truck?

[71chevylowrider]

Yes, it's a shorty, Sure, I'll try to squeeze under that thing when i get home, the back's are 10" with 305/50R/15's They don't tuck, but they sure do squeal

[powell72]

Dirtball had one built for his truck in Greeley at Northern Colorado Driveline for $300, a little far from you but at least that gives you an idea on price.

[GREASEMONKEY72]

as far as i know all the new cars have aluminum driveshafts

[Longhorn Man]

i know I replace about 5 or 6 every winter at work.

[GREASEMONKEY72]

Originally Posted by Longhorn Man

i know I replace about 5 or 6 every winter at work.

sounds like fun

[kbs71]

I went to the local "Warehouse" (bone yard) and got a 4" aluminum driveshaft out of a 95 chevy 1500. It was @ 3/4" shorter than my 2 piece for my LWB. The yoke sizes were diffrent that the ones on my TH350 and 12 bolt rear so I went to a local tranny shop and they had the right u-joints for it. Cost me $65.00 for the driveshaft and @ $45.00 for the u-joints installed. I had to trim out the opening in the crossmember some. But I drove it for over 2 years before I started project "OH S&!T, look out for that Mazda truck, 20 feet in front of me" rebuild. All I ever did was regularly grease the u-joints. There still tight.

[valentini]

Thanks to everyone for your replies. I ended up going with Indland Empire out of california. However, I purchased it from summit racing, they gave me a better price.

Hopefully the length will not be an issue, I will try to post some more info after I get the truck up and running, very close.

[timcos]

Originally Posted by Longhorn Man

i know I replace about 5 or 6 every winter at work.

Is that good or bad?

If it is a very low percentage of all the shafts out there...then it may not be too bad.

Why are they replaced?

Are they more replaced than regular metal drive shafts?

Tim

[Longhorn Man]

in the 5 years at the shop, I have only swapped out 3 or 4 steel shafts... the alluminum ones, simply don't hold up.
Now... GRANTED... thes shafts are breaking from abuse, one of our local DHL hubs is staffed with retarded idiots. They'll hit the gas in the snow, spin the tires, and as soon as they hit dry pavement, the shaft explodes... sometimes violently.

[timcos]

That is great to know. Thanks,

Tim

[valentini]

FYI - The reason I need to go with an alluminum dirveshaft is because of the overall length. I am converting from a two piece driveshaft to a one piece. The issue is related to the critical speed of the driveshaft, or point in which it decides to break. A normal mild steel driveshaft would tend to sag and eventually become out of balance at the length I need. The length is still wrather long for alluminum but it is supposed to hold up better. So hopefully it will work.

[LUV2XCLR8]

LongHorn?

Lwb?

Got pic's?

[Longhorn Man]

why not stick with the correct 2 piece shaft? It won't sag,or cost you $500

[71chevylowrider]

Hey andy? These driveshafts that keep breaking, what diameter are they? Mine looks peretty beefy, & beleive me, I abuse it on a regular basis, & soon I will be installing an Eaton posi unit, should I be worried?

[GREASEMONKEY72]

Originally Posted by Longhorn Man

why not stick with the correct 2 piece shaft? It won't sag,or cost you $500

and IMO would be better and stronger to i beleive than a one piece

[Shane]

Originally Posted by valentini

FYI - The reason I need to go with an alluminum dirveshaft is because of the overall length. I am converting from a two piece driveshaft to a one piece. The issue is related to the critical speed of the driveshaft, or point in which it decides to break. A normal mild steel driveshaft would tend to sag and eventually become out of balance at the length I need. The length is still wrather long for alluminum but it is supposed to hold up better. So hopefully it will work.

Don't mean to sound out of line, but whoever told you the aluminum shaft was stronger than the steel is spreading false information. Critical speed, center of gravity, moment of inertia, or whatever else we need to cover... the tubular steel shaft will NOT "sag" any sooner than the aluminum shaft. Aluminum has less "torsional" strength than steel, and that is what we are talking about here. A twisting motion.

Not meaning to sound rude, and hope you don't take it that way, I just hate to see false information passed on in a place like this with so many readers.

[Longhorn Man]

the alluminum shaft can be made longer without whipping, like a steel shaft will do. This is why a steel shaft shouldn't e made over six feet long.
71lowrider... I couldn't tell you the diameter.... but they are friggen huge though....I'll guess and say 5 or 6 inches.

[71chevylowrider]

Thanks Andy, hey? Are you getting my PM's?