Got Torque?

[GMCwantsLS1]

Too long just means for the speed it is turning.

[99 red silver]

I just don't see how that would happen going down the road. One haft needs to spin and the other has to stop. Or the front most spin quicker than back. Metal could have been bad in that area (weak). What can cause that? Rear end or Trans? One needs to be locking up. If all is moving at same speed something need to stop moving. Allen have you check rear end and trans for damage the last time? Thinking out load.

[GMCwantsLS1]

what happens is the ends are supported by the tranny and diff so the middle of the driveshaft bends until it hits something then it stops, the ends keep on twisting until it breaks in half.

[1BADHD]

Originally posted by GMCwantsLS1@Jul 8 2003, 10:28 AM
Too long just means for the speed it is turning.

I dont see a problem, since it aluminum. A steel, smaller diameter is a lot heaver than an aluminum 4". Less rotating mass. Hell, I had mine out last week and could walk around one handed. I dont know what it weighs, but, I bet it dont weigh 40 lbs with the yoke. So a sixty somthing incher is gonna wiegh a lot less.

[Domeskilla]

yes, it will weigh less.. but that is like having 100 feet of pipe rotating and then 40 feet, what will be stronger? You hit a point and i'm not sure what the point is with each diameter, where the size of it, makes it unstable for the speed at which its traveling. Allen races his truck 3-4 times a month, on slicks, and hard. So the average shaft, isn't no big deal, but the abuse he puts them at, is why they might have said that an aluminum shaft to his applicatoin, might not be safe, but he's going to go with an aluminum one, we'll see if it breaks. If it does, then something else is completely wrong.

Lets pray tho!

[GMCwantsLS1]

Last time I was at the track I saw an aluminum one (f-body) get twisted off just like Allen's. He said that was his third shaft to get twisted off like that.

[farmtruc]

It sure is hard to determine what is happening. The first time my shaft broke, i replaced the trans tailshaft, and rear pinion yoke.
This time i'll check the rearend, and replace the same two i did last time. I think the rearend is in need of some adjustment after what just happened.
I know you can't go to long a a shaft that is too small in diameter, my shaft is probably 3" or less, about the last 1 ft. of the shaft on both ends is actually about 2.75 " , don't know why they did that. I called driveshaft unlimited again and they are make me a race shaft. We'll see how it turns out, i'm still going with a denny's shaft.

thanks for all the input,

anybody know what i should do first in trouble shooting my problem.

i guess first i'll check out all the drivetrain,

what's next?

thanks,

allen

[farmtruc]

I just got off the phone with denny's driveshaft again and he explained some stuff.

Some of this you already know, just trying to sum it up.
Every shaft has a critical speed. The larger the diameter the higher the critical speed. My 4.10's and overdrive don't help much with this critical speed either, nor does the length.
In third gear the ratio for engine rpm and shaft rpm is about the same. So engine is turning 6500 rpm so will the shaft.
For the 4" diameter shaft i'm going to get, it has a critical speed of about 7500rpm in overdrive. So i guess the shaft would be spining about 6500rpm in third, i don't think i would ever hit 7500rpm in overdrive.
I can see now how a smaller 3" or 2.75" shaft would be a lot worse for critical speed.

Since the stock silverado's have a long shaft i bet the shaft is at least 4" in diameter and i was just told the SS shaft is 5" in diameter.

He explained that when a shaft hits critical speed, the shaft begins to wobble right in the center of the shaft, hey mine broke in the center, lol. I guess critical speed for a smaller diameter shaft is a lot lower for a 3" or smaller shaft.
I can also see how it broke if the shaft was damaged in the center or was weak.

I'm going to end up getting the HD Aluminum shaft and 1350 series yoke. This sux, i could be spending this money on mods , not repairs.

anymore input is greatly appreciated,

allen

[99 red silver]

Hope that works. How long before you are up and running again?

[farmtruc]

Denny said it will take about 10days to get a HD one made and about 3weeks for a light duty one.

I guess i'll make all the measurements tonight and order one. I'll take my shaft in tomorrow to driveshaft unlimited so they can make me another one, then i'll just get my money back when my other shaft comes in.

this sux , maybe we can get enuff info together to fix the next person having these problems, heheh


thanks,

allen