Just looking for some thoughts on this. I had my 05 regeared about 2 months ago and I used gears from rons machine service. I didn't specify when I called him so I ended up with the us standard ones. The first pinion seal lasted 2 days.. guy that did the work swapped it and now its leaking again. I do have a driveshaft type vibration at around 85 mph which I always had but with the 373s it was at a higher speed obviously. I pass through it often now but don't stay at that speed. It smoothes out around 90 mph and anything below 85 its gone as well. I mention this as a possibility... however my 04 does the same vibration thing nearly with the stock 410s it has and it doesn't have any issues. I am wondering if my pinion isn't machined correctly or something. I know these gears are basically yukon rejects but I am just looking for ideas. There is no burrs or edges. I may get my driveshaft balanced ( 2 piece steel since its an hd) but am not sure if it would whip enough to cause a leak.... kinda doubt it. The diff is the 9.5" 14 bolt.

 

Are you using the correct seal for the Yoke you have???

I don't have any specific information but there are different seals designs and they need to match the yoke. Other wise you would need to take the yoke off and inspect the it for wear in the sealing area.

 

after flipping through the fsm im thinking that the pinion preload is incorrect. is there any type of noise associated with the vibration? anyway to check and see if the preload is correct with disassembling the whole rear end the manual specifies 25-50 in/lbs required with ring gear installed.

 

As far as I can tell there is only one seal available for the 97 and newer 9.5" 14 bolts. Even RMS only lists one or alternately there is a 1979-1997 version as well. The kit part number I got was for the newer diff but that doesn't always mean anything. I don't know what the replacement seal that lasted the next 2 months was or where the guy got it......... but probably the same napa I deal with. He is an ex GM tech of 25 years or so that went on and started his own shop.... and honestly is the only one I have ever met with any brains around here. I may buy a new yoke and a new seal this go around however because I don't know what the surface of the existing yoke looks like. I am not the one swapping the seals because quite frankly I paid someone else to do the job the first time and he can deal with it. Oddly enough though this whole paying someone else got me into this differential mess to start with....... and it's not like I don't know how to do this stuff, I just don't want to, lol.

It probably is a wear groove thing on the existing yoke causing the seal to leak...... that makes the most sense. The vibration in the driveshaft just drives me nuts.... just like it does in my 04 as well. The u joints and carrier bearing are good so I will yank the shaft and have someone spin it to see what is up.

 

You said the truck was an 05. Which year 14 bolt did you get??? Did you re-use the yoke from the 14 bolt???

I feel your frustration. The same exact thing happens every single time I pay some one else to do something.

 

Also check the housing for a gouge. Some of these guys get wreckless with their seal removal tool and gouge the housing. A little bit of filing, and a little bit of GMS around the outside of the seal will take care of it.

 

The 14 bolt that was in the truck, lol..... it's a 1500HD. So you know, LQ4, 80E, NVG 246, 9.25" IFS, all 2500HD stuff short of the rear diff, t case and rear section of the frame. They all have 9.5" 14 bolts, always have. When I buy parts for this truck I just buy them for my 04 2500 light duty if it's powertrain related. Otherwise all I ever get is half ton junk even if they punch it in as a "1500 HD". The front diff died from someone messing something up in it while changing axle seals..... now my new front diff has an axle seal leak too...... and no the vent line is good. This is just getting frustrating lol. So when I swapped fronts I dropped to 4.10 and of course had the rear rebuilt to accomodate.

That sounds like a good idea too. I probably will just swap the yoke myself as I want to see wth is going on.

 

If it's a wear groove in the yoke, consider a speedi-sleeve repair. And I like to clean the splines and apply new Teflon paste sealant to them when going back together.

 

Me too on the sealant always laughed seeing the spline leak. Swagelok brand Swak works awesome for this stuff, and I use it at work so I have tons of it. I wish that's all this was. I actually have never seen anyone ever use the sleeve on anything, balancers, yokes or otherwise. I know they exist just never have seen anyone actually use one. I will see how much old Napa wants to gouge me on the yoke and go from there.

Hopefully this ends this, and I am sure it will.

 

Replaced the yoke and the seal today. I dunno.... the parts I pulled look absolutely fine so I guess time will show. The seal was undamaged and the yoke had no visible wear worth talking about. I guess now I will see if it starts leaking and then get the driveshaft balance checked when I get home again. Like I said it does have a vibration at around 80 mph that is gone by around 90 mph so it may be the culprit too. I really don't know.