TheGrendel
Active Member
Is it me or does it seem he’s getting too much pinion rotation on acceleration?
Got an interesting one… 🤔
- Thread starter Physicistkev
- Start date
Physicistkev
Member
When I rewatch the longer videos, it’s disturbing how poor the pinion angle looks and how much movement there is.
But remember, the fisheye lens exaggerates movement up close and gives linear things a horizontal curve when there isn’t one. That’s just how the optics work. I’m going to do a shot with my phone today. I’ll post that and see if there is a significant difference between a fisheye and non-fisheye lens.
I think there will be, but there’s no proof like empirical proof.
But remember, the fisheye lens exaggerates movement up close and gives linear things a horizontal curve when there isn’t one. That’s just how the optics work. I’m going to do a shot with my phone today. I’ll post that and see if there is a significant difference between a fisheye and non-fisheye lens.
I think there will be, but there’s no proof like empirical proof.
Physicistkev
Member
Here is the video from this morning. Using an iPhone mounted on the rock slider. I couldn't mount it in the same place as the GoPro from the last video as it was too close to the differential. Also, the focus is on the driver side, rear, lower control arm mounting bracket, so the driveshaft is a bit out of focus. Anywho, I think the deflection looks A LOT less severe, which I would chalk up to the fisheye lens on the GoPro. Also, I think the pinion angle looks more appropriate in this video. My thoughts, but I'll let you all weigh in.
I still think the pinion angle needs to come down as it's at -1 degrees and I want to see -2 degrees, as noted earlier in the thread.
I still think the pinion angle needs to come down as it's at -1 degrees and I want to see -2 degrees, as noted earlier in the thread.
Mike Pierson
Hooked
The rear OEM driveshaft, since it’s so long and has the rzeppa joint, can be off a bit and it doesn’t cause issues. If the boot is damaged and it’s slung all the grease, it can stop it from sliding which can put pressure on the pinion and bearings when you articulate, which could cause them to fail. Also, check the boots at the joints.
CalSgt
Hooked
If your pinion bearings are starting to fail the pinion snout should get super hot.
When I set up a differential I use an IR thermometer to check temps on the pinion snout and diff cover during break in.
New bearings and gears will produce more heat than broken in ones but still shouldn’t get much over 250 degrees while broken in ones don’t typically get over 200. If preload is set wrong or the bearings are failing they start to cook themselves.
Take it out and run at highway speed for a while and get differential temperatures.
If your bearings are going bad it will be catastrophic (expensive) once they’ve had enough and give out. Far cheaper to repair now than it will be to replace the carrier/locker.
If you have any friends with the same Jeep you could probably swap rear drive shafts for troubleshooting whether it’s the Rzepa or something else. Drive shafts usually are catastrophic when they fail on the highway too, they can shatter transmission and transfer case housings and beat the shit out of everything else.
When I set up a differential I use an IR thermometer to check temps on the pinion snout and diff cover during break in.
New bearings and gears will produce more heat than broken in ones but still shouldn’t get much over 250 degrees while broken in ones don’t typically get over 200. If preload is set wrong or the bearings are failing they start to cook themselves.
Take it out and run at highway speed for a while and get differential temperatures.
If your bearings are going bad it will be catastrophic (expensive) once they’ve had enough and give out. Far cheaper to repair now than it will be to replace the carrier/locker.
If you have any friends with the same Jeep you could probably swap rear drive shafts for troubleshooting whether it’s the Rzepa or something else. Drive shafts usually are catastrophic when they fail on the highway too, they can shatter transmission and transfer case housings and beat the shit out of everything else.
Physicistkev
Member
How long is “a while”? I did 70 for about 15 minutes and the rear differential cover was 197. The snout was 201. Is that enough time to allow the heat to build up?
CalSgt
Hooked
Yeah, I would think that is plenty enough time and speed to check the temps and you’re right in the ballpark of normal temperature wise.