aluminum driveshaft

**JunkyardZ** · 09-02-2011, 08:08 AM

Any real benefits to running a lighter weight driveshaft? Got me thinkin the other day when I was under an 02 35th SS. I saw that it had an aluminum driveshaft on what looked like a bone stock car. Did some of these cars come with them? Mine sure doesn't. Also who makes a good one?

**Firebirdjones** · 09-02-2011, 09:00 AM

Aluminum driveshafts in the 4th gens first appeared in 98 I believe, and it was on the performance axle option If I remember right. Which should have been all the 6 speed cars and the autos with 3.23's.
Both my auto with 3.23's and my 6 speed have the aluminum piece.

Honestly though, they are of a thin wall design and not very strong. I've seen them twist like a prezel. I would much rather prefer a thicker wall tube in aluminum or chrome molly.

The advantage to lighter driveshafts are less recipricating weight for the engine to turn. Puts more power to the rear wheels. Any time you can reduce recipricating weight, whether it be clutch setups, smaller torque converters, internal transmission parts, lighter rods and pistons, rifle drilled axles, light weight rotors, wheels and tires etc.....You'll put more power at the rear wheels.

**tatertot91** · 09-02-2011, 02:24 PM

Originally Posted by Firebirdjones

Honestly though, they are of a thin wall design and not very strong. I've seen them twist like a prezel.

They dont take good to hard launches

**pajeff02** · 09-02-2011, 05:46 PM

I swapped out our stock aluminum d/s for an aftermarket PST unit which ran right around $400.00. Here is a comparison shot of the two:

**Ortiz11b** · 09-03-2011, 06:58 AM

I just added the 3" gm driveshaft to my a4 car (for 75 bucks).. i did a 3.42 gear swap and driveshaft.. with your 3.73 it should help alot...the steel driveshaft may be giving you a vibration at higher speeds.. there not as strong as the steel,,, i was told for a a4 car,,, there not bad, but prone to snapping,,, mine is just a daily driver,, so figured the less rotating mass would be better... just personal preference i guess,, im on a tight budget,, good luck

**JunkyardZ** · 09-04-2011, 10:16 AM

Originally Posted by Ortiz11b

I just added the 3" gm driveshaft to my a4 car (for 75 bucks).. i did a 3.42 gear swap and driveshaft.. with your 3.73 it should help alot...the steel driveshaft may be giving you a vibration at higher speeds.. there not as strong as the steel,,, i was told for a a4 car,,, there not bad, but prone to snapping,,, mine is just a daily driver,, so figured the less rotating mass would be better... just personal preference i guess,, im on a tight budget,, good luck

So you got the gm aluminum one for $75? That ain't a bad price, was it used? I should have weighed mine when I had it out the other day to see what the savings would be.

**JunkyardZ** · 09-04-2011, 10:19 AM

[QUOTE=pajeff02;2695953]I swapped out our stock aluminum d/s for an aftermarket PST unit which ran right around $400.00. Here is a comparison shot of the two:

That looks good. Is it pretty close in weight to the factory one. I would imagine its a little heavier due to being more heavy duty.

**pajeff02** · 09-04-2011, 02:17 PM

Just a bit heavier -- but note that it lacks the steel damper that is situate behind the front u-joint on the stock shaft. Another nice difference is that it upgrades from 1310 (or 1320?) size u-joints to the 1350's.

**Ortiz11b** · 09-04-2011, 03:26 PM

Originally Posted by JunkyardZ

So you got the gm aluminum one for $75? That ain't a bad price, was it used? I should have weighed mine when I had it out the other day to see what the savings would be.

Yha it was used... i have a local speed shop that has a few used for 75... there on ebay and craigslist for around 100 or so,,, and ive read the gm aluminum driveshaft is around 7.5 #'s lighter than the steel...

**INMY01TA** · 09-11-2011, 03:14 PM

Mine came with one.

**35th-ANV-SS** · 09-11-2011, 04:23 PM

That's pretty impressive...and dangerous. Did you have a loop on it when it snapped?

**INMY01TA** · 09-11-2011, 04:25 PM

Originally Posted by 35th-ANV-SS

That's pretty impressive...and dangerous. Did you have a loop on it when it snapped?

Yes I have a loop, broke at the rear tho as you can see. Broke right at the line and just didn't go anywhere. Seen a dozen or so others do the same thing.

**35th-ANV-SS** · 09-11-2011, 04:27 PM

I've seen a couple break before, never in person though, just pics. Like Jeff, I also have the 3.5" PST unit. Still have the GM AL DS in the basement collecting dust.

**Firebirdjones** · 09-11-2011, 07:13 PM

Originally Posted by INMY01TA

Yes I have a loop, broke at the rear tho as you can see. Broke right at the line and just didn't go anywhere. Seen a dozen or so others do the same thing.

Yep, I've watched them twist like that, with street tire no less at the Norwalk starting line. The surface was sticky enough to hook nicely, and two of them twisted in half within a few minutes. I was running some of my best 60 foot times that day, it's a hookin' track.

Funniest part was the guy walking around the bleachers afterwards carrying both halves around like it was some kind of trophy,,,hahaha.

**sjohnson904** · 05-20-2013, 03:07 AM

So I twisted my drive shaft off my 2000 Firebird Ws6 the other day trying to do a hard launch. I got a replacement from another guy that had one sitting in his garage from a 2000 Camaro SS. I drove it around a little over the weekend and now it feels like I have a vibration. Especially when I let off the gas. I have never done that before and as this car is my baby with only 40,000 miles on her I am now worried I did some other damage. Does any one have any idea as to what I could've done? Scared to even drive it now until I get it figured out. Thanks for the help.

**pajeff02** · 05-20-2013, 03:37 AM

Could be a bad u-joint in the driveshaft you installed, a balance issue, pinion angle problem... or maybe you tore up something other than the driveshaft. Did you make any suspension changes while you were under the car? How is the trans mount? I am trying to remember if the A4 and M6 cars use the same driveshaft, or if there is a length difference... anyone?

**Supershafts** · 05-20-2013, 04:13 AM

The factory AAM AL shafts aren't strong, AAM used the lighter diameter wall and i think they used a different AL class i had often thought they did this so the shaft would break before the rear.

The weight difference of AL vs STL will give your car better response and improve mileage, and AL doesn't transmit vibrations like STL does, but depending on the tube style and wall AL can be like a speaker.
AL and STL are both strong, and AL can do things better than stl and live in high hp areas where stl can not.

See your local Driveline shop and have them build you one, and ask they leave the china on the shelf, many shops have and use china crap in there shafts even the big advertized shops with fancy adds and other draw your attention gimics. So be sure and ask they not use china in your shaft, or you'll be unhappy when the china parts fail as others have been.

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sjohnson904, it sounds as if you have a joint issue or angle issue since it gets worse off the gas, im leaning more toward a joint issue, have a look at them and you may have to remove the shaft from the car to be 100% sure the joints have no play or one isn't seized as i suspect with your issue.

.

**sjohnson904** · 05-20-2013, 12:35 PM

Thanks and it has new u-joints on the shaft and I didn't mess with anything else. I just replaced it with another drive shaft and new joints.

**pajeff02** · 05-20-2013, 12:43 PM

Upon installation of the new u-joints, did you verify that there is no binding? It is awful easy to press a cap in too far, or bend a yoke, and end up with a joint that is too tight.

**bberretta** · 05-29-2013, 11:15 PM

I have the same one as pajeff02- got it when I put the 9" in. Slightly larger in diameter but about the same weight as the stock one. I'm sure you can pick up a stock one at a parts yard for cheap if you're looking for one. My dad has laid claim to my old stock one for his '55 street rod.