working on a bagged 51 pickup and here are the angles. i took all of these measurements at ride height with the truck on the ground. i pulled the driveshaft and slid under i have this digital level/angle finder and placed it on the flange on both ends the trans is angled down and measures 87 degree the rear end pumpkin is also angled down at 83 degrees what concerns me is shouldn't the rear diff be pointed way up if the trans is pointed down so the angles do not conflict? I know these angles are done by + being Up and - being down but i clearly have two - negative angles./ in order to bring the diff housing into a + range i might need to cut the control arms and lengthen as it seems i need alot of movement. or do i just bring the diff up to around 86 degrees keeping it slightly angled down? i hear to allow 1 degree for load wrap up i started all of this because fluid keeps seeping from the pinion seal and the u joints keep wearing out./
I have always shot for trans 3 deg "down" and rear 3 deg "up"..... looking at your numbers your trans should be fine. The rear however, needs to come up a good amount. This is the reason the u-joints are going.
Yes....it needs to be fixed. If you just keep replacing the u-joints eventually it will destroy the rear end. Posted using the Full Custom H.A.M.B. App!
If I read your numbers correctly, the trans is 3 degrees down, which is fine. The rear end appears to be 7 degrees nose down, and should be 3 degrees nose up. So the rear end needs to be rotated up.
we just spent the good part of the morning messing with this, we got things better but we are still off by 2 degree, will this matter as under load a 4 link supposed to move up about 1 degree so in theory we are pretty darn closer than we started. i need to order another threaded rod from speedway that is 1 inch longer so we have more adjustment on the heim joint. def having two friends made this go much smoother than expected.
Simple things can be hard to grasp. I was probably on my third hot rod before a driveline company told me u-joints had to have deflection to properly lubricate. They also told me that for severe duty, you need high quality u-joints with superior seals than the chain stores usually sold. They had examples of the severe duty Saginaw joints to show the difference in what I was using. I had burned up a few ujoints and pretzeled a drive shaft in order to get that education. No need to get uptight about it. Maybe step away from your intarwebs for a while and try to remember what we are in this game for.
Nobody is uptight here. We just cover this, weekly. There are over 500 threads that cover it, on this site, alone. One search away.
To answer your question, while totally equal is usually what you look for, if you are 2 degrees off on the back, you probably will be OK..... I would try it and run it for awhile and see what comes up..... I would not cut the mounts loose, or modify the 4-link for 2 deg, without trying it first. Also, double check your yoke where it goes into the trans now that you made the adjustment, you will still want about 3/4" of stick-out (yoke not bottoming in trans).... adjusting the pinion angle will close up your gap some... Tom
still vibrates the floor pretty bad almost seems worse. hey guys someone at the local Napa who used to race pro stock cars told me yesterday i should have the trans down 2 degree negative and the pinion down 2 degree negative, now doesn't this conflict with the phasing of the shaft and the total angle?
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