I agree.
Tailshaft Angles
- Thread starter frankenyota
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However these axles articulate and in parrallel they stay relitavely parallel, but in a non-parallel matched angles set up when you compress or drop the spring the pinion will stab up or down, forcing your angles to change and they will change in opposite directions as one gets more aggressive and the other flattens out.
The vibration is caused by the transfer case output having constant angular velocity, but because the yokes don't go through their matches range of motion together the pinion end actually has a sinusoidal angular velocity. In our rigs it creates vibration and wear, on a 130' Locomotive turntable for CSX, it literally snaps 5" diameter drive shafts during braking
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pb4ugo
SILVER Star
Tom Woods website has a great technical section And driveline geometry 101 section which is simply explained.
A couple of yrs ago I altered my driveline to center rear output T/case along with a hybrid centered 40 rearend. I also flipped the rear springs for an additional 3" of wheelbase to help with driveshaft angle and length. I played around with pinion angles and T/case output angles, trying to get them parallel to each other. At full droop I had binding similar to the OP. My end result was that my T/case and pinion are not parallel to each other but are close. I wanted to achieve no binding at full droop with a std Ujoints. They are probably within 4 degrees of each other or less. I have no vibration on blacktop driving. It's been yrs since the mod so i can't recall the actual numbers.
A couple of yrs ago I altered my driveline to center rear output T/case along with a hybrid centered 40 rearend. I also flipped the rear springs for an additional 3" of wheelbase to help with driveshaft angle and length. I played around with pinion angles and T/case output angles, trying to get them parallel to each other. At full droop I had binding similar to the OP. My end result was that my T/case and pinion are not parallel to each other but are close. I wanted to achieve no binding at full droop with a std Ujoints. They are probably within 4 degrees of each other or less. I have no vibration on blacktop driving. It's been yrs since the mod so i can't recall the actual numbers.
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Well
Well what? Agree that the last one is unconventional, rarely done in automotive, but if the joint angles are correct, will work. The front on the '80 comes this way from the factory and know a couple that run that setup on the rear. Works well, gets the pinion and shaft up out of the rocks.
pics please.
If nothing else, pointing the pinion up past the tcase output on a leaf sprung vehicle is a sure fire way to make the pinion bind and snap under acceleration (and resulting axle wrap).
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Looked, don't see any rear pix handy, that was a big deal when it was first done, like a decade ago. Will shoot some when I'm around one of those rigs. The front from the LX450 NCF document, how they are setup from the factory.
Agree, there are considerations that need to be taken into account for any setup, may or may not be a good option for the application. The point was, it is an option, has been done, does work. On the '80 rear, with adjustable links, it's trivial, on a leaf spring rig, maybe not so much.
Is that solid or IFS?
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Solid, front and rear.
Now I see what you are talking about. That Is a specific situation where the pinion and the tcase output are both pointing up. That is generally not the case on rear outputs.
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Generally not the case on anything automotive, can't think of another that uses that setup?
Thats why I asked if it were an IFS set up, in which case the diff would not translate with the wheels. Parallel shafts will be closer to the same angles as the axle moves up and down however non-parallel matched angles will get out of alignment very quickly with suspension movement.
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Back from work and thought I would add some pics. Tailshaft set up is parallel with equal angles.
Clearanced the uni joints yokes to just clear when at full droop.
Clearanced the uni joints yokes to just clear when at full droop.
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- #34
I think i will try this set up on road with the spring perches tacked in and see what the vibrations are like.
Read that land rovers run an unparalleled tailshaft set up?
Have not seen this myself.
Read that land rovers run an unparalleled tailshaft set up?
Have not seen this myself.
I would set it up parellel couple degrees down on diff
So it doesn't vibrate on acceleration
And run a centre limit strap to keep the joints from binding
But not limit it at ends of axle
So it doesn't vibrate on acceleration
And run a centre limit strap to keep the joints from binding
But not limit it at ends of axle
Did you have to clearance both ends of the driveshaft? Also, I'm not sure what the angle finder on the driveshaft is telling us...
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Only clearanced the transfer end, you can see some marks in the first picture.
The angle gauge was me checking the maximum uni working angle.
The angle gauge was me checking the maximum uni working angle.
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Man that front yoke is tight! I guess the good news is that the only time you will reach that angle is going downhill, when there won't be a load. Uphill should be much more sanguine. Of course, if you're a bunny hopping fool, a limit strap is cheap insurance.
I v-notched my yoke deeper than that on my 45. It's not the part that's going to fail.
I v-notched my yoke deeper than that on my 45. It's not the part that's going to fail.
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- #39
Found a front double C tail shaft from a 83 LN46 Hilux in my spare parts which is the correct length for my set up so fitted it up. Just need to replace the uni’s In the double C.
First picture is at full droop, second at ride height.
First picture is at full droop, second at ride height.
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I recently shimmed the rear axle in my 40 up (running 60 rear) so it would properly align the pinion to the drive shaft (i.e. parallel) for running the CV (double cardin) shaft. I think having the pinion 1 deg lower would be even better but it is working quite smooth on the highway now. Looks like you've got it set now.
