View Full Version : Vibration after 8.25, help me think it through...
Dredwolf
09-30-2012, 08:41 PM
:confused:
So I swapped the D35 ABS axle in my '99 for a JY '99 8.25 today, and used the 8.25 driveshaft from the same '99 XJ. Same lift (approx. 4.5"), but I get an acceleration vibration now, but it disappears once past 30 mph.
Did not have this vibration with the D35. I did NOT rebuild the 8.25 on purpose, I have rear leaves on the way, and will be re-gearing anyway.
Rear leaf packs will be 3.5" RE units. An SYE is planned, because of the nose lenght of the 8.25, do I need shims in the meantime?
I need to go buy an angle finder.
4.3LXJ
09-30-2012, 08:44 PM
Here is how to get that sorted out
http://www.xjtalk.com/showthread.php?t=7299
Dredwolf
09-30-2012, 08:49 PM
Here is how to get that sorted out
http://www.xjtalk.com/showthread.php?t=7299
Thanks for the reference! A lot of my driveline tools from my CJ days disappeared when my mother got "help" cleaning the "shop" area of my father's garage when I worked overseas.
I'll get an angle finder. I could just go ahead and bite for an SYE I guess.
4.3LXJ
09-30-2012, 10:29 PM
If you have a smart phone, you can get a free app for leveling
Dredwolf
10-01-2012, 06:16 PM
If you have a smart phone, you can get a free app for leveling
True, I have that app on my work phone, but I found a new HF angle finder in the top of my tool box.
Working on the XJ is an excuse to NOT have the work phone with me.:D
Brasscatz
10-02-2012, 09:38 PM
I could just go ahead and bite for an SYE I guess.
I remember a tip from an XJ Talk Show from a long while back that Steve (4.3LXJ) suggested. (Steve please correct me if I'm wrong) But if you feel like going back to the JY or even looking around craigslist/ebay you could get a slip yoke from a YJ instead of an SYE because they are made to work with steeper angles. That's my plan for the future :wink:
4.3LXJ
10-02-2012, 11:02 PM
That is correct. YJ slip yoke is 1/2" longer and will accommodate more bend than the XJ yoke
Dredwolf
10-04-2012, 08:43 PM
okay, today was the 1st day it was not raining, so I tried to get a measurement on the two angles....not too successful.
But visually,my driveline angle looks like the CV one....the axle pinion is almost a straight line with driveshaft.....but the transfer case has almost NO angle, 3-4 degrees?:confused:
Lower the transfer case?
4.3LXJ
10-04-2012, 08:46 PM
You could lower the tcase, but you might need to shim the axle instead. That would be my first option. IMHO better than lowering, but both acceptable
Dredwolf
10-04-2012, 10:30 PM
You could lower the tcase, but you might need to shim the axle instead. That would be my first option. IMHO better than lowering, but both acceptable
I am used to shims for the axle to rotate the pinion angle UP....but on this 8.25, the pinion and driveshaft are almost perfectly aligned....shim it more?
I did not want to post the numbers until I checked again this weekend, with perfect light, 2 cups coffee, vitamins and a good breakfast....I got 3 degrees on the t-case and 13 on the pinion......:confused:
I'll check it again after I get the springs installed.
LizardRunner
10-23-2012, 12:29 PM
Sounds like the pinion is in need of a reduction in angle by around 10 degrees if your using a conventional set up, ie. the stock 8.25 drive shaft. MIght only be a few degrees out or dead on if going CV joint style.
Dredwolf
10-23-2012, 08:25 PM
I am using the stock 8.25 drive shaft from the same donor vehicle that supplied the 8.25. My XJ has a estimated 4.5" lift..., pinion angle appears to be straight in line with the driveshaft. That is one potential problem. I am used to shimming the pinion UP, is shimming the pinion angle DOWN common?
I did find the source of at least part of the "felt" vibration...the PO took a sawsall to the exhaust near the cross member......so the exhaust is suspended by the header.....and the cross member :bang: but the exhaust stops before the rear axle, so no place to easily fab hangers:mad:
The little cheap exhaust hanger installed by PO is literally supporting none of the exhaust weight, so besides the banging, it sends vibration through the chassis anytime you accelerate.:rolleye0012:
HD Offroad Engineering shackle brackets are on the way, so I am holding on trying to measure pinion angle until the 3.5" leaf packs and shackle brackets are installed.
Plus an SYE is in the near future, Carolina Driveline runs a special on the SYE kit and matching driveshaft.
4.3LXJ
10-23-2012, 08:55 PM
yes, shimming down is common
Dredwolf
10-23-2012, 09:18 PM
yes, shimming down is common
Thanks for the info, I'll see if I can't sort all of this out when the shackle brackets and new leaf packs get installed. Still trying for around 4.5" of lift and 33's that clear well.
I have been tempted to just order a couple of sets of shims to have on hand, but I'll wait.
Sandman4182
10-24-2012, 07:03 AM
I also had a vibration on min but not due to changing to the 8.25 it was after I lifted it I do have a 8.25 I dropped the TC 1 1/2 I think and it went away. Till I can get a SYE. I might still have the template I used for it let me know.
Jeepster19
10-24-2012, 07:14 PM
If you have a smart phone, you can get a free app for leveling
Which app did you pick?
4.3LXJ
10-24-2012, 07:20 PM
It just says level. It measures in tenths of degrees
Jeepster19
10-24-2012, 07:30 PM
It just says level. It measures in tenths of degrees
Thanks.:D
Dredwolf
10-24-2012, 08:14 PM
Which app did you pick?
I have a free one on my smartphone that is "carpenters" set of levels, etc, I think there is such for Android and iOS.
And they have such at your local HF...not bad if you are not using one every day.
Dredwolf
10-24-2012, 09:01 PM
I also had a vibration on min but not due to changing to the 8.25 it was after I lifted it I do have a 8.25 I dropped the TC 1 1/2 I think and it went away. Till I can get a SYE. I might still have the template I used for it let me know.
I have been looking the dropped cross members too, but I guess I need to install everything first....this XJ ran smooth with the same lift and a D35. I swapped the D35 for the 8.25, and used the drive shaft from the donor vehicle, and picked up this vibration under gentle acceleration....runs smooth at 55-60 mph.
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