Questions about my 85 FJ60 SOA rear pinion angle?? (1 Viewer)

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Nov 27, 2013
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Ocoee Fl
I am in the middle of my SOA project and I have come to the point where I need to set my rear pinion angle. I have swapped my SF 60 axel for an 80s FF axel. My transfer case is at 89 deg and I have my pinion mocked up at 86. It just does not look correct to me and before I burn it I would like some feedback. I will be lengthening my Tom Woods shafts. They are not double cardigans just single joints that is why I didn't point it at the T-case. I have read where people point it at the case run a double and call it a day. I have read set them parallel to each other and reduce the pinion by 2-3 degrees. I'm running stock fj60 springs at the moment and 6" anti-inversion shackle OME or Man-a Fre can't remember where I got them. The truck is only sitting on its weight in the rear the front axel is not back from the cut and turn.
 
At that steep of an angle, pointing the pinion at the transfer case will starve the pinion gear and front bearing of oil
 
Noted, I never gave starving the pinion bearing much thought before but that makes sense.
 
Transfer case and pinion angle.

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That looks pretty good. I usually set the pinion 5 degrees up from the output flange. Your looks to be about 4 degrees. You will have no issues with oiling with it like that.
 
Ok I tacked up the rear perches, when I get the front axel in and truck back on it weight (all 4s) I will double check and post pictures before I burn it. Do I need to put any additional weight in the rear before I take the final measurement. It’s empty now usually has 200lb of recovery gear and tools/spare parts.
 
Ok I tacked up the rear perches, when I get the front axel in and truck back on it weight (all 4s) I will double check and post pictures before I burn it. Do I need to put any additional weight in the rear before I take the final measurement. It’s empty now usually has 200lb of recovery gear and tools/spare parts.
Yes add weight as if it will be loaded how you usually have it (tools, gear, spare parts, tire, etc).
 
Ideally the flange angles would be identical while operating. We shoot for 2 degrees low on the rear to compensate for the angle rising under torque. Five degrees is too much.
Now when you measure the slope of your drive line? Is that to be done after you set your pinion degree? And my drive shaft is 4” to short so can I use a string or bungee to measure the slope?
 
Make the pinion the same as the tcase. I am not seeing why you can’t. Point it at the tcase for a DC shaft otherwise it should be the same as the tcase.

I wouldn’t worry about oiling, I have set many at 10*, I just overfill the diff and have had no issues.

Yes you can use a string, I use a laser on a level but have used a string before.

Cheers
 
Ideally the flange angles would be identical while operating. We shoot for 2 degrees low on the rear to compensate for the angle rising under torque. Five degrees is too much.
Sorry but you are wrong. 5 degrees is fine and will not cause any vibes. I have five SOA cruisers in my yard to prove you wrong about that one. I do it to get the d-shaft up out of the way from the rocks if I am putting on new perches . I have done many tests near my house on a nice long slightly downhill slope where I can modulate the throttle from acceleration to deceleration when I am having issues with a rig getting vibrations from the rear d-shaft. 5 degrees is just fine and does not cause vibrations.
 
Five degree high plus axle wrap will vibrate. If you never go on the freeway, that's one thing, or if you have a double cardon on the t-case side. There is no driveline shop in the world that would intentionally set you up five degrees off.
 
I drive 60% on road and 40% Offroad. I am a few days from setting the pinion angles going to try to get the front axel under tonight and get the weight on it. I think I’m good with the setting them parallel then kicking the pinion up 2deg while it is loaded with all the normal weight and the a extra 300lb.
 
Then I believe once I get the angle set I can get the slope of the drive line and determine if I need the drive line shop to add a double or not.
 
Ok so I finally got the rear pinion set up. I got the truck back on the ground and was going to run a standard drive shaft like I had custom made from Tom woods a few years back. But after finishing the SOA and getting the ride height set. I set my pinion parallel to the transfer case. I was at 20deg on the drive line slope so that will not work so I had Tom woods length my shafts to 44 1/4 and add a double joint at the t-case end. So now my driveline shaft slope angle is 17deg and my pinion angle is 14 which give me 3deg on the u joint at the pinion and the other 2 can figure it out lol.

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Just an update I have 5,000 miles on the set up not a single vibration with the angle. I did toast a u-joint. Tom woods reused it because I told them to. I had replaced it this year but after putting 1,700 miles on the road from Florida to Windrock for GSMTR and 300 off-road at Windrock it tosted it. So I replaced it and so far so good.
 
You DO have a double-cardan drive line, so what I previously posted about making the flange angles the same doesn't apply.
I now have a double cardigan drive shaft. I originally was just going to have TomWoods extended it. It was made by them a few years back. But once I got the truck on the ground and realize the angle was going to be to much on the joints with my yokes parallel. So I kicked the Pinion pointed at the t-case and tom woods extended and attached a double.
 

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