AB6DO

Doing a 2007 a classic 5.3/4L60E swap into my 1948 Chevy pickup. Engine/ transmission down angle measured at 4 degrees down with full weight on suspension. Is 4 degrees up on on pinion acceptable?

Geoff1200

I believe the pinion should not be upward, especially in a leaf spring suspension, my .02

79LS1FOX

iTrader: (11)

4 degrees up should be fine they should cancel each other

jimmyg

If you have a smart phone, use the tremec driveline app . It's free. Works great

garys 68

iTrader: (1)

yes and no....the angles have to be the same and opposite....just like you have.
But the driveshaft has to be within a certain spec too. Measure on all 4 wheels, you need the diff, engine, and driveshaft angles.

Project GatTagO

iTrader: (7)

^^^^This

Andrew

Dimeomboost

I agree with this but I also know from experience ive had it anywhere from 0. Up to about 3.5 or 4 i use my angle finder to start then ill switch to my digital setup when I'm setting it up permanently I've had it move a little from welding on perches and it didn't have a drastic effect on it but I'd still want it as close as I could get it

Taxman20

iTrader: (11)

If its leaf spring truck, you always want down angle on the rear.

chiaj144

iTrader: (4)

Don't forget to allow for movement of the rear under acceleration. They way it's set now is were you want it under acceleration, not at rest.

Taxman20

iTrader: (11)

^^^ that's why you start with downward pinion angle on leaf springs. The spring will wrap up in the front and the angle of the pinion goes upwards.

Project GatTagO

iTrader: (7)

Statements like this are meaningless unless you measure the angle of the driveshaft.

The front and rear operating angles need to be equal, opposite, and as small as possible but not zero. Depending on the rear suspension the rear operating angle might need to be set lower to compensate for axle wrap, but this depends largely on the rear suspension design and the bushings being used. Rear ride height also plays a big role in all this.

Andrew

S10xGN

iTrader: (11)

Unless you're using quality traction bars like Cal-Tracs. Then there is minimal pinion rise...

Project GatTagO

iTrader: (7)

Exactly...so back to what I posted above.

Andrew

Taxman20

iTrader: (11)

The angle of the trany is irrelevant. You just don't want the driveshaft straight with the U-joints. They need to be at an angle. Yes, the rear suspension dictates the optimum angles. Of course none of our race cars had leaf springs. The theory is still the same. Pinion angle is set as needed that at launch the squat of the rear suspension gets the pinion angle to where it needs to be during a run. in a leaf spring car this is always down. And unless this is a real track only race vehicle, I wouldn't over complicate it. If a person is that serious then we should talk about location of brake calipers too. Yes it matters.

Taxman20

iTrader: (11)

Agreed. But you still don't want an up pinion angle.

Project GatTagO

iTrader: (7)

The angle of the transmission is not irrelevant. Sigh....

The guidelines that I outlined in post #11 is what's important.

Andrew

Taxman20

iTrader: (11)

I should rephrase it. Its not relevant to the way the vehicle drives or handles.

chiaj144

iTrader: (4)

Winner winner. I shoot for 3* or less working angle on both u joints.

BMR Sales2

iTrader: (40)

To simplify what was hashed out here;
Measure engine and trans, and the axle should be about 2-3* less than what the engine measures. So if the engine is measuring 4* downward, the rear should be up 1-2* to allow for axle wrap. That way under load they will be close to the same angle

garys 68

iTrader: (1)

I'm guessing since this is a 48 pickup, it will be street drive, not race only.
Instead of asking peoples opinions, go to the experts, follow their advice:
http://www2.dana.com/pdf/J3311-1-HVTSS.PDF