driveline angles

Hey guys I need some help quick. I'm in the middle of modding my trans cross member and I'm now stuck on driveline angles. For reference, I have the Inland Empire Driveline: Power Train Set Up pdf downloaded that Garys 68 gave me for reference. Here are my issues/questions:

I'm having a hard time getting a reading off the differential for a driveline angle. I believe I'm getting 1deg down as a reading. Does this sound about right? What's the best way to get a reading off the diff?

According to the above listed source, I need to know the angle of the driveshaft. I don't have a drive shaft that I can fit in place. How should I get this measurement? Is it really needed (seems important)? I thought of tying a string between the 2 yokes, but I feel that will be inaccurate.

Could I calculate the old driveshaft angle? If I assume the old transmission was at 3deg down, and the diff was at 1deg down, then I believe the drive shaft would have to be 2deg up (-3+2 = -1, 2+-1= 1, -1+1= 0; see the linked document). Can I use this number?

I know this is a lot, but any guidance would be great guys. Thanks a bunch.

I too am curious how that could ever be accurately measured even with the body OFF the car.....but, when I swapped trannies from a Muncie to a 700 and later on to a 200, all I did was set the Muncie/bellhousing on the floor, take my framing square and measure so much offset from the locating pins on the housing/engine....to the tailshaft mount.....

and then do the same with the new trannies.....

AS I RECALL the 700 was a inch more, so it sat a inch lower on the modded support than the Muncie....

the 200 seemed to be like the Muncie...so it sat straight on the cross member....

never an issue....the 700 swap was done in '97, before there was any net group discussions on the topic, the second, I just did it the same way...

laterally they were all on the same mount line on the cross support, so I figgered no harm there....

:chinese:

Hey I just went through this on my car. I took my reading off the yoke.

The diff should be up and the trans down. If your only 1 deg down on the diff its possible that your measuring it correctly and the diff is off. Check your diff pinion bushing because that could be bad.

You really should need a driveshaft to measure this.

Did you see this thread?
http://www.vettemod.com/forum/showthread.php?t=338

I have measured some factory installed cars and found that a differential pointed down at 1 degree is pretty normal. Most driveline angle diagrams show an equal but opposite condition (trans tail down/Diff pinion up). It is also possible to phase a driveline with the trans tail down and the pinion down. I think you are asking about a condition like this (trans tail down 3 degrees and diff pinion down 1 degree/red line is 0 degree):



For this to work, the driveshaft is in at 1 degree. That means having the trans yoke .52 higher than the pinion. I was not able to get my T500 in at 3 degrees (more like 4).

Also, consider that ther is already 1 degree angle built in from side to side (engine is offset 1" and pinion .5").

Gene, You're absolutely right it a pain to get a reading off the diff. I have a good amount of trouble trying to get it. That's why I was looking for some verification to the validity of 1deg down.

Fuelie, no I never saw that thread. It had some nice info in there.

So there is no way to get the proper driveline alignment without a driveshaft? That's very annoying because I though that I could only measure once the transmission is mounted. However, I can't mount it until I fix the crossmember, and I can't finish that until my driveline alignment is set. I love circles...

Well, If I do measure for the driveshaft now, it can't be much different from now and when the trans is mounted. However, I was really hoping ot have this crossmember done this weekend.

And thank you BBShark for giving me hope that my diff could be at 1deg down. One detail I fogot to mention: when I redid my suspension 2 years ago I put in a new poly snout bushing, which could have changed the angle.

Man, what a pain this is.

Guys, I would like to know just what instruments you all are using to determine the angles.....the only thing I have that maybe could be used with max difficulty would be my father's old carpenter's adjustable angle steel rule/square....it's only 18" long though so how in hell to set it up??

I looked at

http://www.drivetrain.com/parts_catalog/drivetrain/driveline_angles_and_phasing_problems.html

from the other thread here, and somehow that just don't impress me as being very accurate....

:stirpot:

greg75vette said:

Gene, You're absolutely right it a pain to get a reading off the diff. I have a good amount of trouble trying to get it. That's why I was looking for some verification to the validity of 1deg down.

Fuelie, no I never saw that thread. It had some nice info in there.

So there is no way to get the proper driveline alignment without a driveshaft? That's very annoying because I though that I could only measure once the transmission is mounted. However, I can't mount it until I fix the crossmember, and I can't finish that until my driveline alignment is set. I love circles...

Well, If I do measure for the driveshaft now, it can't be much different from now and when the trans is mounted. However, I was really hoping ot have this crossmember done this weekend.

And thank you BBShark for giving me hope that my diff could be at 1deg down. One detail I fogot to mention: when I redid my suspension 2 years ago I put in a new poly snout bushing, which could have changed the angle.

Man, what a pain this is.

Click to expand...

I forgot to mention. If you are using one of those magnetic protractor style levels and you can't get it on the pinion yoke, there is a machined pad that is directly behind the axle yokes. The magnetic deal will sit right there and it's perpendicular to the pinion. It's the surface that is machined for the rear cover.

BBShark,
I looked for that surface and didn't see one open. It is on the back of the diff somewhere near the cover, right? I'll take a better look tomorrow assuming the weather holds out.

And for the record, I did use a magnetic angle finder on both the trans yoke and diff yoke.

If you can get to the pinion with the angle finder, that's the best place. The surface I was talking about is the machined surface where the cover mounts. Look right behind the axle yokes. There should be a little flat surface there.

Edit: Found a picture

pinion offset

BBShark said:

I have measured some factory installed cars and found that a differential pointed down at 1 degree is pretty normal. Most driveline angle diagrams show an equal but opposite condition (trans tail down/Diff pinion up). It is also possible to phase a driveline with the trans tail down and the pinion down. I think you are asking about a condition like this (trans tail down 3 degrees and diff pinion down 1 degree/red line is 0 degree):



For this to work, the driveshaft is in at 1 degree. That means having the trans yoke .52 higher than the pinion. I was not able to get my T500 in at 3 degrees (more like 4).

Also, consider that ther is already 1 degree angle built in from side to side (engine is offset 1" and pinion .5").

Click to expand...

BBshark, you mentioned the pinion is offset .5", is this a virtical measurement, because the half shafts are the same length and I need to know if I am missing something. My pinion is currently centered in the chassis with the engine/trans offset 1" to the right/pass side with a 3deg tail down. Just asking for some clairifacation on this, thanks.

voodoovette said:

BBshark, you mentioned the pinion is offset .5", is this a virtical measurement, because the half shafts are the same length and I need to know if I am missing something. My pinion is currently centered in the chassis with the engine/trans offset 1" to the right/pass side with a 3deg tail down. Just asking for some clairifacation on this, thanks.

Click to expand...

Yes, the half shafts are equal length but the pinion is offset 1/2 inch to the passenger side and the engine is offset 1 inch to the passenger side. This makes approximately a 1 degree (equal but opposite) angle as looking from above.

What's strange to me is with every tranny R&R on my '72 over the years, is having to pry the tailshaft to the pass side by almost a inch, in order to get the mount bolts to line up....true for the Muncie, 700 and this 200 auto....go figger...front frame don't look hit, alignment is fine...wheel position in the wells ok....

:search::amused:

BBShark,
Thanks for the pic. I was looking for a smoothed machined surface off the cover. Ill check that measurement off the cover and see what I get. I don't trust the pinion measurement much due to the way I had to tip the gauge to read it.

Gene,
Funny you should say that, because I have a load strap pulling the trans to the drivers side. It was about 1/4" off from the pinion. Everything lines up pretty good now.

Thanks for the tips guys!

mrvette said:

Guys, I would like to know just what instruments you all are using to determine the angles.....the only thing I have that maybe could be used with max difficulty would be my father's old carpenter's adjustable angle steel rule/square....it's only 18" long though so how in hell to set it up??

I looked at

http://www.drivetrain.com/parts_catalog/drivetrain/driveline_angles_and_phasing_problems.html

from the other thread here, and somehow that just don't impress me as being very accurate....

:stirpot:

Click to expand...

Gene this is what I use.
http://www.harborfreight.com/digital-angle-gauge-95998.html

Fuelie74 said:

mrvette said:

Guys, I would like to know just what instruments you all are using to determine the angles.....the only thing I have that maybe could be used with max difficulty would be my father's old carpenter's adjustable angle steel rule/square....it's only 18" long though so how in hell to set it up??

I looked at

http://www.drivetrain.com/parts_catalog/drivetrain/driveline_angles_and_phasing_problems.html

from the other thread here, and somehow that just don't impress me as being very accurate....

:stirpot:

Click to expand...

Gene this is what I use.
http://www.harborfreight.com/digital-angle-gauge-95998.html

Click to expand...

:shocking:Wooden the car have to be deal level f/rear??

or if the shaft was in place, just to compare the differences between diffy/tranny pan/driveshaft?? using that plane on the end of the rear cover...

:shocking::beer: HF is right up the street 30 bux....hummm....

mrvette said:

Fuelie74 said:

mrvette said:

Guys, I would like to know just what instruments you all are using to determine the angles.....the only thing I have that maybe could be used with max difficulty would be my father's old carpenter's adjustable angle steel rule/square....it's only 18" long though so how in hell to set it up??

I looked at

http://www.drivetrain.com/parts_catalog/drivetrain/driveline_angles_and_phasing_problems.html

from the other thread here, and somehow that just don't impress me as being very accurate....

:stirpot:

Click to expand...

Gene this is what I use.
http://www.harborfreight.com/digital-angle-gauge-95998.html

Click to expand...

:shocking:Wooden the car have to be deal level f/rear??

or if the shaft was in place, just to compare the differences between diffy/tranny pan/driveshaft?? using that plane on the end of the rear cover...

:shocking::beer: HF is right up the street 30 bux....hummm....

Click to expand...

When I did mine earlier this spring I zeroed my gauge off the frame then measured both. Had 3 up and 3 down. Once I got my driveshaft in I verified and it was the same.

I used a $8 or $9 orange plastic angle finder from Home depot, worked just fine....

Car was supported under the frame with four jack stands in the garage on (supposedly) leveled floor.... I leveled the whole thing with shims between the jacks and frame, wasn't far off to begin with ... don't remember how close I got the angles but when I started after the TKO conversion it was horrible, felt like a stubborn horse at 50mph... after my "adjustments" it's smooth as silk....

I use a poly diffy mount cushion: that thing can be cut and shimmed to adjust the angle of the differential.... that's one thing poly is good for

How important is it for the car to be level? If you take all 3 angle measurements when the car is in the same position, the angle of the car should cancel out, right?

Either way, I'll take a reading off the car frame. I may have never thought of that... :crap:

I also use this angle finder: http://www.harborfreight.com/dial-gauge-angle-finder-34214.html