Mopar Muscle Association UK

Found this in answer to this question in mopar tech.

That's a loaded question. The best answer is....the least amount of driveline or
u-joint angle is the best amount of angle. Try to achieve the least amount of
u-joint angle but don't make it less than 1 degree. A little known fact about
u-joints is that they require about 1 degree of operating angle to get the needle
bearings rotating. If they do not rotate they will fail. Too much angle will also
cause them to fail. The type of rear suspension also plays a big part in setting
the angles as well as the engine/transmission angle. Leaf spring cars have a
need for more downward pinion angle due to spring wrap-up while coil spring
cars control the situation better. Hard acceleration as in the case of a drag race
car requires a different setting than a street driven car. Traction bars, ladder
bars, 4 links, independent rears all have special needs and requirements.

This is very relevant to my range-trol project, thanks.

I presume one also tries to get the same angle at both ends, so that the UJs equalise out the speed fluctuations?

In other words, If I have 3 degrees at gearbox, is it better to have 1 degree at axle or 3 ?

The idea is to have the angles equal when the vehicle is under load, if the gearbox is angled 2 degrees down, the diff would be angled 2 degrees up. Because the axle will rotate in relation to the suspension under acceleration, you need to add in an amount of degrees to take that into account. The suspension design dictates how many degrees you need to add, leaf springs need the most, about 5 degrees off the top of my head...

The center line of the crankshaft and transmission output shaft must be parallel to the center line of the pinion shaft as shown in Figure 1.



You will note that there is some distance between these parallel lines. The distance is caused by the angle of the components and their distance apart.

Planning these component angles is critical. You have to set the components up so their center lines are parallel and so that the angle made THROUGH the U-joints is 3-degrees or less as shown in Figure 2.



While it is possible to run at zero degrees through the U-joints, something more than one degree and less than three degrees seems to run smoothest.

You should also point the pinion down from this ideal position slightly because under load the pinion rises slightly (depending on spring strength and pinion snubber).

Many people get this completely wrong and drop the pinion down with relation to the ground instead of to relation to the UJ angle. They end up with pinions pointing at the ground.

will, found this and it might be more relevant to your project than Mopar.
Dave a while ago I read your thread relating to setting up your diff after fitting the gear venders kit but can,t seem to find it.

Sorry Will forgot the link
http://www.vibratesoftware.com/html_hel ... pshaft.htm

Good stuff. this is particularly relevant to my new car as the engine and back axle mountings are a a little different to the stock set up.

Thanks chaps!

Knightcharger wrote:Dave a while ago I read your thread relating to setting up your diff after fitting the gear venders kit but can,t seem to find it.

It is in the transmission section of my own message board somewhere. The information above is lifted from a thread there which in turn was lifted from that GV installation thread.

Thanks Dave will go mouching TVM

Lifted this from the above thread just shows how complicated it all gets

Bob , been thinking about our conversation last night , don't think i will have a problem with the pinion/GV angle , although the prop shaft has been shortened , hence a steeper angle into the pinion yoke , the angle on the box hasn't changed , nor has the pinion yoke on the diff.

Might not need those plates.

Soooooo , should be OK.

Any thoughts?

Adam effectively the gearbox is nearer the diff casing so the angle the UJ spins through must be greater<
Try putting your new 1000 Hp through it and if it goes tits up just by another overdrive, prop and diff casing £2500 No problem.

Alternatively fit the proper shims and make sure it is sett at 3 - 5 degrees $79 plus delivery?

Rear axle shim package mopar performance parts has developed these tapered pinion angle shims so the pinion-to-drive shaft angle can be adjusted to the correct 5-7degrees. Kit includes 2 each 1 degree,2degree,3degree shims. (6 total shims).
4529536 rear axle shim pkg. 79.95
P5153561 Rear Axle Shim — 1°, 2pcs. 26.50
P5153562 Rear Axle Shim — 2°, 2pcs. 28.50
P5153563 Rear Axle Shim — 3°, 2pcs. 31.5

Do it right first time do it once

I have those shims in stock if you need 'em...

Knightcharger wrote: Try putting your new 1000 Hp through it and if it goes tits up just by another overdrive, prop and diff casing £2500 No problem.


Do it right first time do it once

Bob , better get those shims.

Blue wrote:I have those shims in stock if you need 'em...

Thanks Blue , think Bobs already ordered Alan & me a set , would of forced me to do it anyhow.