inverted driveline angles?

[MAGONSTERZ68]

1968 Camaro Convertible
Hotchkis UCA - Detroit Speed LCA - Hotchkis 600 LB rate springs front - 178-180 lb leaf spring rear
Hotchkis tuned fox shocks front and back
18" wheel, 275 35 18, 25.6" diameter - 3.5 drop in front - 3" drop in rear, 8.5 GM 10 bolt,LS2, 4l65E, zero vibration.
Front ride height measured from fender lip is 25.25 front and 25.75 rear
No odd harmonics accelerating or decelerating and none present at cruising or freeway speeds.

Driveline angles are backwards due to lowering of vehicle?
Engine,trans is 2.6 down - driveline is 2.9 up - pinion is 1.2 down with the pinion angle above the trans/driveline ride height.
Should i try and correct to eliminate the 5.5 and the 4.1 working angles?
if so how best to proceed?
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[csouth]

Probably want to state what vehicle you have to give and idea of how the suspension is setup.

[joeko23]

What is driveline angle? Is that the angle of your driveshaft? If it's a positive number that means your rear end u joint is higher than the transmission, many on here have lowered their cars 3" in the rear, I don't think their rear end is higher than the transmission output shaft. Also you are measuring at ride height? With your cars full weight on the ground? I don't think it makes sense that your driveshaft is pointing up coming out of the transmission.

[MAGONSTERZ68]

Driveline angle is positive 2.8 deg and yes pinion is higher than transmission.
yes ride height on level ground with full tank of fuel minus driver.
no, eng and trans is 2.6 down when connected to driveline which points up forming a downward V with a working angle of 5.5 deg.
driveline is 2.9 up in relation to pinion forming an inverted /\ at a 1.2 deg with a working angle of 4.1 with the pinion angle above the trans/driveline ride height.

[joeko23]

Can you adjust the transmission up to match the 1.2 degrees up on the rear?

[MAGONSTERZ68]

There is some room, i can shim up trans, not sure how much though, will need to raise at least 1.4 deg but not sure how much that is in inches.
Will give it a shot this weekend.

[TheJDMan]

Are you currently experiencing any drive line vibration?

[ctcz28]

Your schematic shows the pinion pointing up 1.2 deg, but you say it's down. Are you referring to the working angle between the pinion and the DS being down? If your trans is pointing down and your pinion is pointing down it's definitely wrong. If the pinion centerline is actually pointing up, at least you're getting close to having the centerlines of the trans output shaft and the pinion being parallel. Shim up your pinion to make it parallel to the trans centerline and see where you are at that point.

[MAGONSTERZ68]

Okay finally got driveline angles close enough, i think any thoughts on new dims?
eng trans 2 deg up, driveline 3 deg up, pinion is above trans centerline pointing up 2.4 degrees.
trans to driveline working angle 1 - driveline to rear pinion working angle 3.0 degrees - final driveline operating angle is 2.9 deg with zero harmonics at all velocities.

[joeko23]

I think you need to lower that pinion angle to something down. If your tranny is pointing up because your rear is higher than your tranny centerline then your pinion angle should be down not up. It’s great you don’t have any vibrations but I think everything will wear out very quickly. Your tranny angle basically has to be opposite your pinion angle so that they cancel each other out. Idk that’s my .2 cents

[MAGONSTERZ68]

alright, raised trans and lowered pinion.
engine/trans is 1.5 down - driveline is 1.9 up and driveline is 0 with pinion above trans center line.
this calcs to front working angle of 3.5 and rear working angle of 2.0 and a final driveline operating angle of 1.5
this look acceptable to anyone else, keep in mind car is lowered and pinion center line is ABOVE transmission center line.

[oakhill510]

Hey, I’m having the same problem. My trans is -3.6, drive shaft is +1.8, and my pinion, I set it to -3.4.

my angle 1 & 2 is out of spec but my working pinion angle is good according to tremec app.
mid I could somehow get my driveshaft into the negative, I’ll have all free light on the angles.

what did you do?

[anguilla1980]

The Magnum T56 in my 69 Firebird points down and my local driveline shop re-welded my leaf perches so the pinion is up, that way they are both opposite the same amount and cancel each other out. I think my trans is like 2.8 degrees down and my rear is 2.8 degrees up.

I've been chasing what seems like a shifter rattle in the higher RPMs but I've also read recently that the pinion should ALWAYS be down, meaning just having them opposite is not good enough. I bought my kit from SST being told I didn't need to modify my trans tunnel and they said nothing about the rear pinion needing to be down. I'm going to be a little pissed if that turns out to be the case and I have to modify my trans tunnel.

Any thoughts?

[Alwhite00]

I’m running into the same uphill driveshaft angle on my 67 Chevelle. When I get the new rear end setup in I think I’m going with a CV driveshaft from the driveshaft shop. I have no room to raise the trans.

[andrewb70]

The Magnum T56 in my 69 Firebird points down and my local driveline shop re-welded my leaf perches so the pinion is up, that way they are both opposite the same amount and cancel each other out. I think my trans is like 2.8 degrees down and my rear is 2.8 degrees up.

I've been chasing what seems like a shifter rattle in the higher RPMs but I've also read recently that the pinion should ALWAYS be down, meaning just having them opposite is not good enough. I bought my kit from SST being told I didn't need to modify my trans tunnel and they said nothing about the rear pinion needing to be down. I'm going to be a little pissed if that turns out to be the case and I have to modify my trans tunnel.

Any thoughts?

If your situation is anything like this:

178447

Then you have to either raise the back of the transmission or use a CV joint driveshaft from The DriveShaft Shop.

Andrew

[anguilla1980]

It is like that. I already have my new DynoTech DS installed, it would suck to get another.

So it's an absolute must that the tail shaft be UP and the pinion be DOWN no matter what?

[Alwhite00]

I know your driveshaft is the opposite direction but the trans and pinion are to be at the same angle parallel. Depending on your rear suspension the pinion should be down up to 4 degrees or so.

178472

[Lonnies Performance]

All of this conversation appears more complicated than it needs to be.
Here are a couple basic items to take into consideration...

1. Generally the engine/trans is angled downward towards the rear (typically 3-5 degrees with respect to the frame) because they are usually mounted higher than the differential.

2. On a leaf spring vehicle, you typically want the pinion lowered an additional 1-2 deg to compensate for torque reaction. Some go as high a 5 on a drag race only application. 3 & 4 link or torque arm style suspensions do not typically have as much rotational issues, but care must be taken to see what happens through the full range of suspension travel.

3. Once you lower the car to where the driveshaft becomes close to straight (under a 2 deg angle), it Is best to start to level the engine & rear to keep some angle in the u-joints. It is preferable to always keep at least 1 degree minimum in each joint. The Ideal situation is to have equal angles on each U-joint, but this contradicts item #2.... so some compromise must be made.

On a very low vehicle (where engine/trans is lower than the rear), I typically start with trying to make the trans & rear parallel, then check the u-joint angle to make sure there is about 2 degrees minimum on each. If not, raise/lower the trans accordingly to get it dialed in. I then tweak the pinion down slightly to compensate for torque reaction.

Generally on lowered vehicles, there is limited suspension travel & stiff springs, all of which help to keep the drive line in alignment & require less pinion offset.

[anguilla1980]

I know your driveshaft is the opposite direction but the trans and pinion are to be at the same angle parallel. Depending on your rear suspension the pinion should be down up to 4 degrees or so.

178472


Thank you. That diagram showing how they need to be parrallel helps a lot.

[Shotaro]

Driveline angle is positive 2.8 deg and yes pinion is higher than transmission.
yes ride height on level ground with full tank of fuel minus driver.
no, eng and trans is 2.6 down when connected to driveline which points up forming a downward V with a working angle of 5.5 deg.
driveline is 2.9 up in relation to pinion forming an inverted /\ at a 1.2 deg with a working angle of 4.1 with the pinion angle above the trans/driveline ride height.

My Camaro has the same problem.

How did you fix it?

Speed tech torque arm suspensions

1970 Camaro Help me. A difficult problem in Japan.

[MAGONSTERZ68]

well as fate would have it, got tired of dragging headers, oil pan and front frame rails EVERYWHERE, was 4" front 3" rear, looked great, rode great as long as there wasnt a dip, off camber or speed bump!
Raised front end to 2" drop and swapped in 1.5" drop rear spring pack, added cal tracs but have yet to set on all fours to check pinion angles, engine not in yet.
Would like to switch to C/V driveline, has anyone used with 750 crank hp 620 tq application? Durability question for street use.

[dhutton]

My Camaro has the same problem.

How did you fix it?

Speed tech torque arm suspensions

1970 Camaro Help me. A difficult problem in Japan.
Install the Speedtech raised tunnel and raise the transmission. Either that or raise the ride height.
https://speedtechperformance.com/product/70-81-camaro-t56-transmission-tunnel-cover/

[dhutton]

well as fate would have it, got tired of dragging headers, oil pan and front frame rails EVERYWHERE, was 4" front 3" rear, looked great, rode great as long as there wasnt a dip, off camber or speed bump!
Raised front end to 2" drop and swapped in 1.5" drop rear spring pack, added cal tracs but have yet to set on all fours to check pinion angles, engine not in yet.
Would like to switch to C/V driveline, has anyone used with 750 crank hp 620 tq application? Durability question for street use.
I used one on my 600 hp 600 tq Camaro without issue.

Don

[Shotaro]

Install the Speedtech raised tunnel and raise the transmission. Either that or raise the ride height.
https://speedtechperformance.com/product/70-81-camaro-t56-transmission-tunnel-cover/

Would you like to raise the tunnel, raise the transmission and raise the engine?

[dhutton]

Would you like to raise the tunnel, raise the transmission and raise the engine?
Just raise the tunnel and rear of the transmission.

[Shotaro]

Just raise the tunnel and rear of the transmission.

I'm thinking of making a tunnel, but is there any other way?

200950

Engine. 2.2↓(87.8)
shaft 1.3 ↑
pinion 2.2 ↑


Thank you

[dhutton]

I'm thinking of making a tunnel, but is there any other way?

200950

Engine. 2.2↓(87.8)
shaft 1.3 ↑
pinion 2.2 ↑


Thank you
You could raise the ride height or use a CV driveshaft.

You could experiment with some pinion shims to get the pinion pointing down but I’m not sure it will help.

https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=Pinion%20shims

Don

[Shotaro]

You could raise the ride height or use a CV driveshaft.

You could experiment with some pinion shims to get the pinion pointing down but I’m not sure it will help.

https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=Pinion%20shims

Don

The rear suspension is equipped with a Speedtech torque arm. You can remove the SIM and lower the pinion angle.

200958200959

Thank you

[dhutton]

The rear suspension is equipped with a Speedtech torque arm. You can remove the SIM and lower the pinion angle.

200958200959

Thank you
I would try removing all the shims.

Keep in mind that Speedtech would have their tunnel mod so the transmission is higher than your case. You really should raise the tunnel in my opinion.

Don

[Shotaro]

I would try removing all the shims.

If you take the SIM and lower the pinion angle, the noise and vibration are terrible.

[Pedigry]

I have fought with pinion vibrations and experimented with different angles on my 70 mustang. This all seems to start with the engine/tranny angle, specifically because it is the least adjustable. I unfortunately have a C6 with a gear vendors overdrive attached to the back, which takes up quite a bit of space in the tunnel so I can't get my angle less than 3.5 degrees. I think at that angle, you will always fight a little bit of vibration somewhere in the rear end. I have it on really slight power lift off and only for a second until the driveshaft loads again. It used to be really bad, but now it's livable.

My point is simply, those with shallow trans tunnels or when running large transmistions like T56 or big automatics will suffer from a higher trans angle because we simply can't lift the tranny high enough to get rid of it. The only solution is to cut the trans tunnel and shim it up or lower the front of the motor with custom engine mounts. Since I'm not crazy about the automatic, I'm going to do a manual swap, lol. That will allow me to get rid of the auto and the gear vendors overdrive. Win/win.

Most drive angle problems and layouts have already been addressed in this thread. I just wanted to add that when you are starting with a 3.5 degree trans down angle, your are starting at a clear disadvantage and overcoming that by simply matching pinion angle, especially when you have a driveshaft up angle to deal with is tough. All bets are off when the driveshaft angle is up because under load it wants to climb even further. And that is, of course, dependant upon what rear suspension you have, coilovers, leafs, triangulated 4 link, straight 4 link, panhard bar, etc. Everyone one has a different amount of climb angle under load. But the general consensus is that with a positive driveshaft angle, all bets are off when it comes to standard driveline practices (i.e. matching trans and pinion angles, specific working angles, etc).

Trial and error for those running an up angle driveshafts is just that, trial and error. Best of luck!

[dhutton]

If you take the SIM and lower the pinion angle, the noise and vibration are terrible.
Then it’s time to cut the tunnel and raise the transmission or raise the ride height.

Don

[Shotaro]

I have fought with pinion vibrations and experimented with different angles on my 70 mustang. This all seems to start with the engine/tranny angle, specifically because it is the least adjustable. I unfortunately have a C6 with a gear vendors overdrive attached to the back, which takes up quite a bit of space in the tunnel so I can't get my angle less than 3.5 degrees. I think at that angle, you will always fight a little bit of vibration somewhere in the rear end. I have it on really slight power lift off and only for a second until the driveshaft loads again. It used to be really bad, but now it's livable.

My point is simply, those with shallow trans tunnels or when running large transmistions like T56 or big automatics will suffer from a higher trans angle because we simply can't lift the tranny high enough to get rid of it. The only solution is to cut the trans tunnel and shim it up or lower the front of the motor with custom engine mounts. Since I'm not crazy about the automatic, I'm going to do a manual swap, lol. That will allow me to get rid of the auto and the gear vendors overdrive. Win/win.

Most drive angle problems and layouts have already been addressed in this thread. I just wanted to add that when you are starting with a 3.5 degree trans down angle, your are starting at a clear disadvantage and overcoming that by simply matching pinion angle, especially when you have a driveshaft up angle to deal with is tough. All bets are off when the driveshaft angle is up because under load it wants to climb even further. And that is, of course, dependant upon what rear suspension you have, coilovers, leafs, triangulated 4 link, straight 4 link, panhard bar, etc. Everyone one has a different amount of climb angle under load. But the general consensus is that with a positive driveshaft angle, all bets are off when it comes to standard driveline practices (i.e. matching trans and pinion angles, specific working angles, etc).

Trial and error for those running an up angle driveshafts is just that, trial and error. Best of luck!

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it's very difficult. [emoji20]

[andrewb70]

You can solve this by using a dual CV driveshaft.

Andrew

[Alwhite00]

I ended up with a CV driveshaft from the driveshaft shop in my 67 Chevelle. 80mph on the expressway with no issues.

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[Shotaro]

I ended up with a CV driveshaft from the driveshaft shop in my 67 Chevelle. 80mph on the expressway with no issues.

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202527

It seems very expensive.

1967 Chevelle cool[emoji41][emoji106]

[andrewb70]

It seems very expensive.

1967 Chevelle cool[emoji41][emoji106]

Yes, but it is the right solution to your situation.

Andrew

[Alwhite00]

It seems very expensive.

1967 Chevelle cool[emoji41][emoji106]

Believe me. I didn't have a CV driveshaft in the budget nor a 9" ford but now that it's done I am extremely glad I did it. I put 8k on it so far and planning a color tour to Tennessee from Michigan in October and when driving that many miles I can actually enjoy the trip.

[NorCal-SS]

Believe me. I didn't have a CV driveshaft in the budget nor a 9" ford but now that it's done I am extremely glad I did it. I put 8k on it so far and planning a color tour to Tennessee from Michigan in October and when driving that many miles I can actually enjoy the trip.

Ah jeez that throws a wrench in things for me too!

So on a lowered A body, even with raising the trans tunnel and adjustable upper rear arms, a double CV driveshaft is still required? Damn!

And yes love your 67 too! Since I’m already mid thread-jack, how high are your wheel arches from the ground?

[Alwhite00]

Ah jeez that throws a wrench in things for me too!

So on a lowered A body, even with raising the trans tunnel and adjustable upper rear arms, a double CV driveshaft is still required? Damn!

And yes love your 67 too! Since I’m already mid thread-jack, how high are your wheel arches from the ground?

Wheel arches to the ground is not a constant measurement as tire size dictates where it will sit. If I put smaller diameter tires on it ne number will be smaller but the suspension hasn't changed.

I could get you a measurement from the center of the wheel to the wheel arch if that would help you.

Btw. If you could get the engine and trans up high enough to get the driveline angles acceptable you would be fine but in my case I would have to severely raise the tunnel and I didn't want to do that. I wanted to use stock carpet.

Also. I have a single CV joint at the trans end. Normal U-joint on the pinion end

[Shotaro]

I ended up with a CV driveshaft from the driveshaft shop in my 67 Chevelle. 80mph on the expressway with no issues.

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202527

This shaft cannot be attached to Speed ​​Tech Torque Arms.;(

[nostoptrial]

Is that because of a specific physical interference issue, or?

[andrewb70]

This shaft cannot be attached to Speed ​​Tech Torque Arms.;(

Why not?

[Mr Nick]

I have a single CV joint at the trans end. Normal U-joint on the pinion end

I went with the same single CV shaft from DSS this year as well. Odd pulsing vibrations on the highway are a thing of the past. The front angle is what it is, which is about 3.5* up. I set the pinion operating angle to 1* down and it's smooth as can be.

[Shotaro]

Is that because of a specific physical interference issue, or?


yes. "There is no clearance between the torque arm and the shaft."

[andrewb70]

yes. "There is no clearance between the torque arm and the shaft."

Pictures, please.

Andrew

[Alwhite00]

202654

[Shotaro]

Pictures, please.

Andrew

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[andrewb70]

Your driveshaft is too short.

[Shotaro]

Your driveshaft is too short.

short? I installed a Detroit Speed ​​leaf spring and changed it to a Speed ​​Tech torque arm. Shafts are the same. And with leaf springs there was no noise or vibration.

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[andrewb70]

You may have multiple problems. The driveshaft is definitely too short and you probably have driveline angle issues as well.

[Shotaro]

You may have multiple problems. The driveshaft is definitely too short and you probably have driveline angle issues as well.

Where can I measure the correct shaft length?

[andrewb70]

Where can I measure the correct shaft length?

I would push the slip yoke all the way into the transmission, then pull it out .75 to 1 inches, then measure from u-joint center to center.