help with driveshaft and pinion angle

[Macdaddy1]

So I have a 1965 c10 with a ls 5.3 and tremec tko 500 trans. I have read all of the threads on pinion angle and I think i understand most of it. My pinion angle is 9.1 degrees up so I adjusted my trans angle to 9.2 degrees down and then I put in a PVC pipe to simulate the driveshaft. It looks like the driveshaft will hit the spot in the frame where it goes through ( where the carrier bearing attaches). Anybody have any helpful suggestions?

[SkinnyG]

If you can, try to get your operating angle of each u-joint closer to 3°.

If you're going to run lowered, you will need to reduce the transmission angle as well. 9° is a LOT.

[The Rocknrod]

Also make sure your suspension is at ride height when measuring.

[PGSigns]

I pull the springs when setting one up with out all the weight on the suspension and set stuff at ride height as mentioned above. Also do you know for sure that the cover on that trans is at the same angle as the output shaft? Is this a short bed? hard to tell from the pictures and that piece of pvc looks really long. And I agree 9 degrees is a lot.
Jimmy

[chevy_mike]

First thing I notice is you don't have a complete truck built. Looks like just the frame. To correctly set pinion/trans angles, you must have your truck fully assembled and at the actual ride height. Full weight will show you where you will sit. If you try to do this as just a rolling frame, all of these numbers will be completely off when the truck is assembled.

That said you want to get your driveline angles closer to 3* a actual ride height, if you want the u-joints to survive. The range I would never get out of is between 1-5* max at ride height. More or less of that range, you are likely to have vibration or u-joint failure issues.

[Macdaddy1]

Yes it is a short bed stepside. Ok how do I mimic ride height without the bed? I set the transmission angle to the pinion angle. I can always shim the transmission if needed. with the bed on the truck would that make the pinion angle move up or down?

[Macdaddy1]

PSGsigns

I believe that the cover on the trans is the same as the output shaft but I will have to check. Whast confuses me is everyone says you should try for 3 degrees but the pinion angle is set at 9.1 degrees. Is that normal or is that due to the fact that there is no weight compressing the springs?

[The Rocknrod]

Is that rear end stock to the 65, need more info/pics on it.

[Macdaddy1]

I believe it is stock. When i bought it the frame and suspension had been done. I will take more pics of it and post tomorrow.

[The Rocknrod]

You transmission mount cross-member is mounted below the frame, how far? Have you had the body on when you set up the engine mounts and trans Xmember?

[Macdaddy1]

The x member is mounted below the frame. I will measure it tonight when I get home. The cab is in painters jail so i do not have access to it to check all of the measurements. I placed the motor in the standard SBC position with stock 6 cyl mounts and speed engineering brackets and am somewhat confident that it is in the correct position.

[Macdaddy1]

This weekend I will pull the springs and rear shocks and see how it sits and measure the pinion angle again. My other real concern is the driveshaft will hit the center part as it passes through the frame.

[wahl4m]

maybe with the eng ine & trans change the rear trans mount needs a spacer under it ? i have had 64-66 trucks that had spacers -between the crossmember & trans mount !

[mongocanfly]

Looks like everything's been covered....the way I set mine up was with the frame level...then set the differential at 3deg up...then I set the engine/trans at 3 deg down...
My IH was at 9deg from the factory so 9deg is not unheard of , but it's not ideal..(think short u-joint life).....3deg is what everybody shoots for though...
If your gonna have contact with the crossmember then you'll have to add a driveshaft loop...
A unsprung trailing arm will have alot of angle changes as it cycles up and down...for weight, you can throw several bags of quickcrete on the back to simulate the bed
But all this setup needs done with the body and drivetrain on the frame...

[Macdaddy1]

Mongocanfly

How did you set your pinion angle at 3 degrees? Any idea what type of driveshaft loop and where to look to purchase?

[mongocanfly]

I had to move my axle perches..so when I clamped the new ones on I could rotate the axle until I got 3deg...then I welded it up....if your truck has had a axle swap by a po it's possible it could have been done wrong.....
Summit,jegs,etc have driveshaft loops.....I prefer the tubing style to the flat bar style but each will work

[Macdaddy1]

What does a driveshaft loop accomplish?

[Macdaddy1]

Would a driveshaft center support bearing work better than a driveshaft loop?

[mongocanfly]

A driveshaft loop will give you more up and down clearance for the driveshaft...

[mongocanfly]

You could also cut out the bottom of your crossmember and fab a piece of flat bar to make a loop...kinda like this....

[mongocanfly]

I wouldnt do a 2pc shaft unless necessary....

[Macdaddy1]

Excellent idea. I will look into that. So I should check my axle perches. Load the rear end to simulate the bed and adjust pinion angle to 3 degrees. Then adjust trans angle to 3 degrees. Order driveshaft and see how much room I have and modify if necessary.

[mongocanfly]

I would get the body back on the frame and sitting on all 4s before making any major changes...

[chevy_mike]

I think you are missing the point, you are likely not going to have it at true ride height without the full cab, bed, interior, engine, trans, etc., etc. Honestly this all should have been mocked into place long before it was full disassembled and off to paint. I even see the same problems with pro builds on the different TV shows. They do some mock up but not with the exact parts they are actually going to use, then they wonder why it the stuff doesn't fit after they already painted everything.

Mock up things first. Yeah it sucks to basically build the vehicle, then completely disassemble, clean/paint and then build the vehicle the second time but it's the only true way to have stuff fit without having to do a lot of mods and paint rework down the road. But what do I know.... only been doing this stuff for 35+ years....

[Macdaddy1]

I get your message loud and clear. Since this is my first ever build I am just learning the ropes. I had thought to finalize the engine and trans placement and driveshaft install prior To the paint being finished. I had no idea that the weight of the cab and bed could effect the trans and pinion angles. I also thought it would be alot easier without the cab and bed as you can gain easy access to those parts. I could then install exhaust etc. etc. and move forward. If it is best to wait I will wait. I do have a 2nd donor cab that I could install temporarily and then would have to do something about the bed. I am thankful for all of the suggestions and help and am not intending to be stubborn in any way i am just trying to figure things out.