I'm looking to sort some drive line vibrations once and for all
I've done a bit of reading but am keen to see if anyone here has set up a high pinion rear diff and with what sort of results i.e. breakages - or not, longevity etc.
Is the set up compatible with a factory vacuum locker? I've read yay and nay re: factory locker compatibility
Saf's are only high pinion front (small diff) they wont fit in the rear, what sort of lift have you got you might need some gearbox spacers to lower the drivetrain?
derk wrote:Saf's are only high pinion front (small diff) they wont fit in the rear, what sort of lift have you got you might need some gearbox spacers to lower the drivetrain?
You can swap the internals of the rear into a front carrier housing to make a high pinion rear.
Just a 3" lift. I have got drop boxes fitted which does lower the gearbox cross member about 10mm. I will possibly need adjustable upper rear arms too which will help, but the pinion angles will still be at fairly steep angles, although at the same angle after adjustment. Also the drive shaft will be fairly stretched out and would potentially need a spacer.
Basically, im wanting to put the drive line closer to factory.
Hi pinion diffs on the front have the teeth on the ring and pinion reverse cut so they are stronger. If you put it on the the back you will end up with a weaker diff setup. Figures are around 30% strength difference between a Toyota 8" high and low pinion driving in the same direction.
How about extending your rear driveshaft and getting the pinion angle right?
I too have 3 inch lift (or had as has now sagged) and 16mm gearbox spacer with no problems. You could try spacing your gear box down another 6mm to 16mm.
Do you know your lift is 3inch? What is the length of your springs in the vehicle including spacers etc?
I hear ya, I read something similar to that on the patrol forum suggesting they were weaker, but then also read there's fellas running 42" tyres with 300hp through them. 30% reduction is fairly significant though! Some say there is quite a whine from running on the overdrive (?) side of the gear, other say no noise...
Drive shaft shouldn't need spacing with a high pinion, yep, the pinion angles will need to be matched too to eliminate vibes. Im mostly looking into the high pinion to put drive line closer to factory alignment.
churchill wrote:Hi pinion diffs on the front have the teeth on the ring and pinion reverse cut so they are stronger. If you put it on the the back you will end up with a weaker diff setup. Figures are around 30% strength difference between a Toyota 8" high and low pinion driving in the same direction.
How about extending your rear driveshaft and getting the pinion angle right?
Slip joint is fecked! universals are a few months old. On the look out for a new rear drive shaft btw
I can only assume they are in phase, (I don't know how to tell lol) but I marked everything when I replaced the uj's and am confident I put it back together correctly. Need to get alignments sussed so I don't have the same problem again.
Swamped wrote:I have a 3in lift with gearbox spacers and no vibes at all. your drive shafts balanced and crosses in good shape and in phase?
Last edited by shaun.paddy on Wed Jun 25, 2014 10:06 pm, edited 1 time in total.
Good to know. Another option for sure. Have you extended you lower arms and or have adjustable upper arms?
So I suppose I don't know the springs are 3" but that's what I ordered lol ... but other than that I haven't measured hub to guard to compare to factory height (any idea of measurements on that?). The free height of the springs probably won't help as I've got flexi coils fitted - about 500mm front and 560 rear free height. The springs flex like a 5"-6" spring but only lift the truck like a 3" spring does.
eins wrote:I too have 3 inch lift (or had as has now sagged) and 16mm gearbox spacer with no problems. You could try spacing your gear box down another 6mm to 16mm.
Do you know your lift is 3inch? What is the length of your springs in the vehicle including spacers etc?
Shocks usually have a serial number you could search to confirm which lift they are for. Some new springs have paper id tags until they wear/wash off. Not looked at my patrol one but drive shafts often have index marks on the splined end and on the female end to make sure they go back together correctly. Phasing means the yokes are the same at either end when assembled so lined up and not 90 degrees to each other or one of the many increments you can get with a spline. Some shafts don't allow incorrect phasing due to a single wider spline amongst the normal splines to make sure orientation is correct.
A pic is worth a thousand words. Look at the pic below. In the top shaft, the 2 joints indicated by the green arrows (ignore the fact that the right-most is part of a double cardan CV assembly) are in-phase because in both joints, the bearing caps held captive in the shaft are both vertical, while the bearing caps that are free (not held captive in the shaft) are both horizontal. If you then look at the bottom shaft, you will notice that this is not the case with the joints indicated by the blue arrows. The left has captive bearing caps vertically oriented, while the right most joint has it's captive bearing caps oriented horizontally. The joints are therefore 90° out of phase.
now that you know what U/J phasing is the reason they need to be phased is the driveshaft doesn't rotate at a constant speed around a U/J it goes slow/fast as it climbs up and rotates around the other side of the U/J (unlike a CV joint that will rotate at a constant speed - hence constant velocity ) so you need both U/J's phased so the driveshaft isn't trying to fight the differences in rotational speed at each end
Thanks for the clarification re: uj phase. I ordered shocks to suit my springs, no worries there, no confirmation needed Better get under the truck for a geez
Swamped wrote:Shocks usually have a serial number you could search to confirm which lift they are for. Some new springs have paper id tags until they wear/wash off. Not looked at my patrol one but drive shafts often have index marks on the splined end and on the female end to make sure they go back together correctly. Phasing means the yokes are the same at either end when assembled so lined up and not 90 degrees to each other or one of the many increments you can get with a spline. Some shafts don't allow incorrect phasing due to a single wider spline amongst the normal splines to make sure orientation is correct.
A pic is worth a thousand words. Look at the pic below. In the top shaft, the 2 joints indicated by the green arrows (ignore the fact that the right-most is part of a double cardan CV assembly) are in-phase because in both joints, the bearing caps held captive in the shaft are both vertical, while the bearing caps that are free (not held captive in the shaft) are both horizontal. If you then look at the bottom shaft, you will notice that this is not the case with the joints indicated by the blue arrows. The left has captive bearing caps vertically oriented, while the right most joint has it's captive bearing caps oriented horizontally. The joints are therefore 90° out of phase.
Cheers, well explained - as above, off to check em
derk wrote:now that you know what U/J phasing is the reason they need to be phased is the driveshaft doesn't rotate at a constant speed around a U/J it goes slow/fast as it climbs up and rotates around the other side of the U/J (unlike a CV joint that will rotate at a constant speed - hence constant velocity ) so you need both U/J's phased so the driveshaft isn't trying to fight the differences in rotational speed at each end
shaun.paddy wrote:Eye balled the bearing caps on the drive shaft side, looks in line. So assumably its in phase. Will know fore sure when it comes out for replacement.
When you take it out would be a good time to check your "pinion angle" on the diff compared to output on Transfer case. Think I read somewhere should be within 1 degree. Just measured mine and was 2 degrees no vibration (remember may have sagged a little). Use both my digital level and smart phone app and both gave me same result.
Get your pinion inclination angle right , I use a starret angle guage , if your output is -5 your pinion needs to be +5 , if they apose gay noises etc happen and vibe , We do +16 arms and adjustable rear uppers , Yes you do need them on 3" lift , !
Would i be right in thinking that as the front diff on a gq is bigger than the toyota 8" that the reduction factor should be smaller, I to have also seen guys in aussie running the hi pinion rear with large hp and tyres and havent read to much Dammage wise.
shaun.paddy wrote:I hear ya, I read something similar to that on the patrol forum suggesting they were weaker, but then also read there's fellas running 42" tyres with 300hp through them. 30% reduction is fairly significant though! Some say there is quite a whine from running on the overdrive (?) side of the gear, other say no noise...
Drive shaft shouldn't need spacing with a high pinion, yep, the pinion angles will need to be matched too to eliminate vibes. Im mostly looking into the high pinion to put drive line closer to factory alignment.
churchill wrote:Hi pinion diffs on the front have the teeth on the ring and pinion reverse cut so they are stronger. If you put it on the the back you will end up with a weaker diff setup. Figures are around 30% strength difference between a Toyota 8" high and low pinion driving in the same direction.
How about extending your rear driveshaft and getting the pinion angle right?
Swamped wrote:Shocks usually have a serial number you could search to confirm which lift they are for. Some new springs have paper id tags until they wear/wash off. Not looked at my patrol one but drive shafts often have index marks on the splined end and on the female end to make sure they go back together correctly. Phasing means the yokes are the same at either end when assembled so lined up and not 90 degrees to each other or one of the many increments you can get with a spline. Some shafts don't allow incorrect phasing due to a single wider spline amongst the normal splines to make sure orientation is correct.
A pic is worth a thousand words. Look at the pic below. In the top shaft, the 2 joints indicated by the green arrows (ignore the fact that the right-most is part of a double cardan CV assembly) are in-phase because in both joints, the bearing caps held captive in the shaft are both vertical, while the bearing caps that are free (not held captive in the shaft) are both horizontal. If you then look at the bottom shaft, you will notice that this is not the case with the joints indicated by the blue arrows. The left has captive bearing caps vertically oriented, while the right most joint has it's captive bearing caps oriented horizontally. The joints are therefore 90° out of phase.
Funny thing is that with the double cardan joint on the top drive shaft the out put at the slip yoke is at a constant velocity. It doesn't actually matter what the phasing is but the diff should be perpendicular to the drive shaft to minimise vibrations if possible.
Im hearing ya fellas, for sure pinion angles need to be matched. Im running +16mm lower rear arms already, uppers haven't been touched yet. And yip, cross gbox cross member could be spaced down a little more too.
High pinion is another way of achieving the same end result of no drive line vibrations and noises but with better overall drive shaft alignment, also not needing to add drive shaft spacer. Will possibly still need adjustable uppers mind you.
Still need to confirm if its a go with the factory locker....
shaun.paddy wrote:Im hearing ya fellas, for sure pinion angles need to be matched. Im running +16mm lower rear arms already, uppers haven't been touched yet. And yip, cross gbox cross member could be spaced down a little more too.
High pinion is another way of achieving the same end result of no drive line vibrations and noises but with better overall drive shaft alignment, also not needing to add drive shaft spacer. Will possibly still need adjustable uppers mind you.
Still need to confirm if its a go with the factory locker....
Have you used a angle guage to check if the rear readings are the same ?
shaun.paddy wrote:Im hearing ya fellas, for sure pinion angles need to be matched. Im running +16mm lower rear arms already, uppers haven't been touched yet. And yip, cross gbox cross member could be spaced down a little more too.
High pinion is another way of achieving the same end result of no drive line vibrations and noises but with better overall drive shaft alignment, also not needing to add drive shaft spacer. Will possibly still need adjustable uppers mind you.
Still need to confirm if its a go with the factory locker....
With the +16mm rear lower arms what tyres are you running? Any Problems under full compression taking out rear guard? Have you chopped rear of rear guard? Standard rear bump stops?
shaun.paddy wrote:Im hearing ya fellas, for sure pinion angles need to be matched. Im running +16mm lower rear arms already, uppers haven't been touched yet. And yip, cross gbox cross member could be spaced down a little more too.
High pinion is another way of achieving the same end result of no drive line vibrations and noises but with better overall drive shaft alignment, also not needing to add drive shaft spacer. Will possibly still need adjustable uppers mind you.
Still need to confirm if its a go with the factory locker....
With the +16mm rear lower arms what tyres are you running? Any Problems under full compression taking out rear guard? Have you chopped rear of rear guard? Standard rear bump stops?
Rear quarters have had a trim up, just on 33" kumhos atm but have some 35" silversones to fit up soon. No rubbing on the 33"s. Bump stops standard but soon to be changed.... after I relocate the lower shock mount points.
derk wrote:Saf's are only high pinion front (small diff) they wont fit in the rear, what sort of lift have you got you might need some gearbox spacers to lower the drivetrain?
You can swap the internals of the rear into a front carrier housing to make a high pinion rear.
Just a 3" lift. I have got drop boxes fitted which does lower the gearbox cross member about 10mm. I will possibly need adjustable upper rear arms too which will help, but the pinion angles will still be at fairly steep angles, although at the same angle after adjustment. Also the drive shaft will be fairly stretched out and would potentially need a spacer.
Basically, im wanting to put the drive line closer to factory.
Does anyone know how long you go with the lower arms before you run into driveshaft lengh problems? Was thinking +16 or +20mm lowers. Have SWB with 3 inch lift.
I did a high pinion a couple of years ago .After having a double cardnel setup. The dude that set it up the first time didnt do it right and cost me a set of bearings etc .Then my friend did it for me and ive had a great run out of it. Never any vibrations very happy with it ,and it gets given a hard time .
Thanks for the feedback Mike, good to hear the set up performs well. I don't suppose your running it with a factory locker by chance? Some say it cant be set up, some say it can???
I scored a diff to pick the bits off just a matter of finding time to get it sorted.
) so you need both U/J's phased so the driveshaft isn't trying to fight the differences in rotational speed at each end 
