Transmission angle help

[fredscarryall]

I have 700r4 that I am putting behind a 327.can anyone tell me what degree of angle the rear tail shaft should be at up or down,have heard about 4 or 5 but not sure on whether its up or down. I also here if you set the trans tailshaft at 4 or 5 down and set the rear at 4 or 5 degree up

[1project2many]

Degree up or down of tailshaft will depend on how the suspension sits and how the engine is mounted. The goal is to get the carb mounting flange level when the truck is parked unloaded. If you have EFI then you have more flexibility, especially port injection.

You also want to consider the U-joint angle when setting up the engine. Optimum U-joint angle is 2-4 degrees. Maximum generally recommended by driveline manufacturers is 7 degrees.

It helps me to make drawings during this stage.

[Rude Dude]

Pics make it easier here you go

[dsraven]

check out this video. it explains a few things. usually driveline angle is set up for 3 degrees, but like mentioned, has to match front and rear. just copy and paste this into google.

http://www.macsmotorcitygarage.com/2...e-and-phasing/

[1project2many]

^^^^^

Yep. Failure to match driveline angles often results in some dramatically broken stuff.

[dwcsr]

Originally Posted by fredscarryall

I have 700r4 that I am putting behind a 327.can anyone tell me what degree of angle the rear tail shaft should be at up or down,have heard about 4 or 5 but not sure on whether its up or down. I also here if you set the trans tailshaft at 4 or 5 down and set the rear at 4 or 5 degree up

Put a level on the intake manifold carb mounting and level left to right and front to back. Then measure the tail shaft angle it should be between 3 & 5 degrees downward at the tail. Match the rear pointing the rear nose up at 3-5 degrees. The drive shaft angle ends up where it ends up, a typical 1350 u-joint can handle up to 20 degrees of maximum angle so don't get hung up on the U-Joint angles.

[OrrieG]

Universal joints need some angle to operate efficiently. They also need to be phased correctly.

http://www.behlingracing.com/behling...-installation/

[1958Warrior]

Depends also on what your running out back , leafs springs, or 4 link ,ladder bars

http://www.quickperformance.com/Pini...ent_ep_45.html


http://www.hotrod.com/how-to/paint-body/91758/


leaf springs 5-7* static angle , under power the rear will rotate up
no limits video shows the same and also CPP tech page 271 in their catalog

At work I've set the drive shaft angle of diesel and electric AC- fire pumps for oil rigs high rises ect. for 10years.The instruction are very clear to have 3* of angle on the drive shafts for the u joints to function properly. They are rigidly bolted down with no movement to very stout I-beam frames.

[solidaxel]

My driveshaft shop tells me that I must have AT LEAST one degree difference from front to back to let the U-joints function, so take your pick!

[1project2many]

GM trucks, at least the 88-99 style, had maybe 1 degree angle across the front driveshaft. The differential never moves as it's IFS. The U-joints brinnel because the rollers basically keep moving back and forth in a very, very small area. Increasing the driveshaft angle slightly can eliminate or greatly reduce this problem.

[joedoh]

everything has been said except,

the added angle doesnt have to be in the xy plane. most rear differentials have the pinion offset so it doesnt point straight at the trans and the u joint working angle is found here.

most chevrolets use a 4 degree down at the trans, so they need a 4 degree up at the diff. this is also why your trans empties itself completely when you pull the yoke. (not really, just YOKEing around)

[ptc]

Originally Posted by solidaxel

My driveshaft shop tells me that I must have AT LEAST one degree difference from front to back to let the U-joints function, so take your pick!

the 1 degree rule is so that the needle bearings rotate inside the cups of the u-joint and dont flatten out over time.... (a long time mind you)

But that has nothing to do with setting 'pinion angle'. Setting pinion angle does require some more understanding of your rear suspension system and everything involved with it.

The stuff put up by 1958Warrior is pretty good. check it out.

[mr48chev]

All good info in these posts. Good reasoning too.

Dave and 1projecttoomany hit on the primary thing with setting the trans angle. Set the engine and trans up with the carb base of the intake sitting level and then go from there getting your driveshaft angles after the engine and trans are set in place.

[OrrieG]

I did not post this before because it is way overkill. But if you are interested in the physics here is a great book made for driveline shops and those fabricating from scratch.

http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

[mrf1002u]

Originally Posted by OrrieG

I did not post this before because it is way overkill. But if you are interested in the physics here is a great book made for driveline shops and those fabricating from scratch.

http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

Thanks for posting that...I was wondering about angles when I swap my eaton for the 14 bolt. The 1 ton has a center bearing and I didn't have a clue what to do there. The book covers it. I even kinda understand it.

Larry W.