Transmission crossmember Install issues

[R.O.B.]

Ok, I'm converting from 4spd manual to 700r4. Finally got torque converter issues worked out and the tranny is mounted to the engine. I bought POL TCM6372 transmission crossmember, the kind that has upper and lower mounts. Apparently only Brothers truck sells this style. Anyway, of course I will have to drill new holes, just my luck. But my real problem is with a brand new tranny mount, if I rest the mount onto the crossmember, the engine is tilted to far down. It's like I need a 2 inch spacer between the tranny mount and crossmember to level off better. What's wrong here?

Rob

[R.O.B.]

After playing with some spacers, 1.25-1.5 is just about right. Is this normal? I Googled some spacers, and saw a 1 inch made specifically for Hooker crossmembers, and a 2 inch spacer, commonly needed on tranny swaps with different tailshafts it says. I can do a spacer, I just need to make sure that:
A) that's the right thing to do and
B) exactly what size I need to keep proper alignment.

Speaking of which, what's a good way to determine proper engine angle?

[LS short box]

To measure the engine/trans angle I use a magnetic angle finder protractor on the engine balancer.
Spacers are no big deal. Use as needed for about? 3 degrees down on the engine/trans.

[R.O.B.]

Thanks Short. I did some internet research, and yes 3 degrees is the accepted norm, along with the carb mounting pad level. All of this at normal ride height.

So with my 1.25 spacer still in there, I measured the angle of the tail shaft. Right at 3 degrees. And my carb pad perfectly level. So that's cool. Weird thing though, my rear pinion angle is at 7 degrees. I haven't touched anything back there, and it's coil suspension, so it's not like it moves around easily.

[Ironangel]

Is the truck lowered? And are you still using the two piece drive shaft? The motor and trans, crank centerline should aim right at the carrier bearing (if you have a two piece shaft?). Take that angle and compare it to the pinion angle. Match your pinion angle to the crank angle. The crank centerline needs to center on the carrier bearing, match that angle with the equal or parallel angle with pinion. That way the second u-joint angle down is cancelled out with the pinion yoke angle up. As long as you dont go over 3 degrees your good. Lowered trucks sometimes require shimming the pinion angle up 3 degrees using wedges between the axle and trailing arms. https://www.youtube.com/watch?time_c...ature=emb_logo. PS. The drive shaft and motor should be inline, the transmission is shimmed at the crossmember to match the crank angle with the drive shaft angle, zero degrees is perfect...

[R.O.B.]

Weird I know. I have the stock ride height, yet 7 degrees @ the pinion. And yes, 2 piece driveshaft, although now I need to get it shortened. Do you think if I drop the rear 2 inches with blocks that would change my pinion angle? It would make the truck level front to rear at least.

[LS short box]

The lowering blocks won't change the pinion angle they just move the axle assembly up. As said above shims to adjust the angle. Or you can purchase trailing arm front mounts that have multiple holes for pinion angle adjustment. That's what I did.

[R.O.B.]

Angle shims sounds like a good idea. Thank you for your help.

[Ironangel]

Lowering blocks dont raise anything, they simply increase the distance between the trailing arms and the axle. That in turn lowers the truck, C/10,s have four points of rear support, two springs and two trailing arms. Lowering a truck 4" or less has little effect or need to start using shims. How you line that primary shaft up with the motor is the key! Shim that 700r4? up to exactly the center of that carrier bearing! Then your drive shaft shop shorten the primary shaft to fit with a slip yoke. I think 7 degrees is a bit much, shouldn't have more than 3 degrees and dropping a truck closes that margin, just keep the pinion angle as close to what the trans output shaft angle is an d your golden...