The Stovebolt Site Forums The Shop Area The HiPo Shop acceptable driveshaft angel?

what is a guideline for acceptable angles between the driveshaft and the tranny output and the rear pinion?

(51 3100 on a 94 s-10 chasis)

here's a tech tip
http://www.stovebolt.com/techtips/driveline/setup/index.html

Grigg

1 to 3 degrees of u-joint angle. Thats measured from the tailshaft to the driveshaft, and from driveshaft to pinion.

Joe

Also note that the pinion and the transmission need to be parallel, so both the front and the rear u-joints are operating through the same angle.

Read the Tech Tip, and follow the links in it to read more.

Grigg

Here's a quick and easy way to do this. Leave the rear axle loose in the u-bolts and install the drive shaft. Put an angle finder on the bottom of the starter, front to back. Read the angle. Put the angle finder on the drive shaft just in front of the rear u-joint, front to back. Turn the rear end, up or down easily, until the angle becomes the same on the angle finder as the angle was when the angle finder was on the bottom of the starter. You are ready to tighten the u-bolts.

I don't think that's right... not measured from the driveshaft to the starter and making them the same...
Again, please read the instructions linked in the tech tip.

Please,

Grigg

grigg,
thanks
all ya wanted to know and more.
this ought to keep me busy for a while.

Grigg,

I'm glad I stumped accross this as I've been looking for about two days for the degrees a motor/tranmissions/rearend need to be set at. So thanks for the information. I do have a question though, does the forumlas and information listed in the PDFs apply to a 1/2 ton application as I saw you have a 1 ton and 2 ton applicaiton. I have a 49 Chevy 3100 that I'm going to be working on. Also I saw on page 7 of the first PDF that the engine-tranmission output was 4°30’ Down. Is the the common degrees that a V8, 350, needs to be set at when the v8 is install in the crossmembers. And please forgive me for asking a stupid question but I take it you do the degree finding and welding when the frame is sitting level, not when the frame is sitting at ride hieght.

Thanks in advance.

In reality the angle of any component (engine, axle, driveshaft..) in relation to horizontal is not at all important as far as the driveline geometry is concerned.
But let me explain,
Obviously you don't want the engine standing on it's tail or snout, it needs to be in the neighborhood of level so the oil system works, but there is plenty of wiggle room there, this usually is not a concern except in off road vehicles.
Now the biggest part of this driveline stuff you need to understand is the angles between the components are the important angles, it's all about the U-joints and the angles they work in. Yes many of the angles even in the PDF instructions are given from horizontal, but that's only because horizontal is a easy reference point, the actual angles relative to horizontal make no difference. Horizontal is only used to easily relate the angles to one another.

The same info applies to big trucks, small trucks, and even industrial (stationary) driveline systems using u-joints.
The one exception may be the torque tube systems like your 1/2 ton truck may have is probably not covered in the manuals. They only have one u-joint, and so long as it is within it's recommended operating angle (it was at factory ride height) there is nothing you can do with it.

As a final note, the driveline angles should be set, checked, and corrected when the truck, complete and ready to travel, is sitting on a flat surface (level is not necessary but can't hurt). If you'll usually be empty, then measure with an empty truck, if you'll always have 1,000 lbs of stuff in the truck, then measure with that stuff in the truck.

Grigg

Grigg - my post says nothing about measuring anything (????). I'm speaking of the placement of the angle finder to get the proper angle for the rear end using the bottom of the starter as an angle that is equal to or the same as the desired angle of the rear end. Nothing about measuring???? This really isn't that difficult!
The drive shaft really doesn't need to be installed if you have a good flat spot on the rear pinion housing to place a magnetic finder.

anybody have any ideas or sources for a degree shim to put between the axel and spring pack? rewelding perch isn't going to happen unless it ends up being WAY out from the tranny.

summit has 2 deg shims at 20.00 a pair.

are there different thickness tranny cross member mounts/cushions that may help with alignment?

this place is a great wealth of info but it seems the project list grows faster than the completion list ;-)

Grigg,

Thanks for the information and the question response.

Carson

Could be we're talking about the same thing in different words?
As I read it the issue I have with your instructions are as follows:
If the angle finder reads the same on the bottom of the starter as it does on the driveshaft, then they are parallel, the U-joint operates in a straight line, no angle change.

In simple terms the pinion needs to be parallel to the starter, not the driveshaft, or more accurately the pinion needs to be parallel to the transmission output shaft (starter is close but may not be exact).

Again, I suggest anyone doing this first read the instructions from Spicer which are found in the tech tip.
There are many different situations and coresponding solutions for driveshafts, giving a clean clear answer here is difficult to do as seen by this example, better to read how and get the info "straight from the horses mouth".

Grigg

Check NAPA, and for sure a spring and driveline shop will have them, and I would think alignment shops too.

I needed a 6.5* shim for my truck and made some out of 3/4" plate I think, tapered from 1/4" on the small end up to something thicker, also incorporated a 3/4" pin to locate in the spring perch, and a 1/2" hole for the spring center bolt hole.
They look just like this http://rides.webshots.com/photo/1484200068080251109FlXuOW

Grigg

I can understand why a lot of folks have problems with pinion angle. Or maybe its just me? I've read about setting pinion angles time and time again and it always seems to be a little different "twist" on how to do it. I've read the links from Spicer, and others, and even they can be confusing to me. Maybe its just "one of those things" that I can't get a clear picture of in my head but at least I get comfort knowing I'm not alone.

I get my nephew to set it with the little digital job like he used at Freightliner and I do the welding!!! Heck, even the way he does it confuses me....which is not hard to do sometime!
So, for those that are having a hard time, sleep well, your not alone either.

grigg
very nice!