Rear Locker Needed

[H32NV]

Rear locker wasn't engaging during the last trip to Moab for Black Sheep Week. Revolver told me on CB that he could see it wasnt engaged. Took it to a differential repair shop here in denver, Western Drivetrain, and they said the locker is toast, and that it would require a new unit. $2150 with labor. Unit cost is $850 itself. New bearings, gears, axle seals.

Does anyone know of a rebuild kit for these or does anyone of the highly modified group have their old e-locker lying around and willing to sell it?

looking for less expensive options with the wedding coming up, any ideas appreciated!

 

[atvspeed4]

Rear locker wasn't engaging during the last trip to Moab for Black Sheep Week. Revolver told me on CB that he could see it wasnt engaged. Took it to a differential repair shop here in denver, Western Drivetrain, and they said the locker is toast, and that it would require a new unit. $2150 with labor. Unit cost is $850 itself. New bearings, gears, axle seals.

Does anyone know of a rebuild kit for these or does anyone of the highly modified group have their old e-locker lying around and willing to sell it?

looking for less expensive options with the wedding coming up, any ideas appreciated!

I was told the same thing originally but took it apart and rebuilt. Usually the pins just round over and the slots they go in lose their shape so the pins skip over. The rebuild kit included new pins and side gears. Cost was around $185 I believe

 

[4speedfunk]

Yes. I just did mine this week. There are two basic kits...both available from Summit Racing.

The first kit is the "gear and locking pins kit", for $120. It comes with new side gears, spider gears, cross pin, cross pin bolt, locking pins, pin cradle, and side gear shims. This will replace the rounded-off pins & driver-side side gear (often boogered where the pins fit into it).

The second kit is the "locking mechanism kit" for $240. This kit comes with the upper & lower ramp plates, three ramp ball bearings, a collar & roller bearing for the coil, six new springs, and a new snap ring. My lower ramp plate was broken into three pieces, so I had to buy this additional kit to get that one piece.

Once you replace this stuff...there really isn't much else to it (except for the electric coil itself). Installation is easy but, you do have to press the carrier bearing off the drivers side to access the snap ring. That one snap ring holds the entire diff together. If you have more than 50k miles you might want to install new bearings while you have it all apart. It's very common that you will destroy the bearing when you remove and reinstall it, so go ahead and replace them...another $40 or so. I'll update this with part numbers later tonight.

You can do this yourself for $500 or so. Probably no need to replace the entire locker.

 

[H32NV]

Thanks all, this is excellent information. Will post photos when I have it apart(1wk +)

Yes. I just did mine this week. There are two basic kits...both available from Summit Racing.

The first kit is the "gear and locking pins kit", for $120. It comes with new side gears, spider gears, cross pin, cross pin bolt, locking pins, pin cradle, and side gear shims. This will replace the rounded-off pins & driver-side side gear (often boogered where the pins fit into it).

The second kit is the "locking mechanism kit" for $240. This kit comes with the upper & lower ramp plates, three ramp ball bearings, a collar & roller bearing for the coil, six new springs, and a new snap ring. My lower ramp plate was broken into three pieces, so I had to buy this additional kit to get that one piece.

Once you replace this stuff...there really isn't much else to it (except for the electric coil itself). Installation is easy but, you do have to press the carrier bearing off the drivers side to access the snap ring. That one snap ring holds the entire diff together. If you have more than 50k miles you might want to install new bearings while you have it all apart. It's very common that you will destroy the bearing when you remove and reinstall it, so go ahead and replace them...another $40 or so. I'll update this with part numbers later tonight.

You can do this yourself for $500 or so. Probably no need to replace the entire locker.

 

[4speedfunk]

Okay...This is the definitive guide to tearing into your H3 rear axle. You can ignore most description pictures you run across...particularly for the Eaton kits. They use a generic photo, that doesn't even come close to the actual part you get. But trust me...the parts below fit your H3, and they are commonly needed anytime you want to do a rebuild. I've done a bunch of these and I have settled on the following list of manufacturers and part numbers. These can be bought from Summit, Jegs, Ebay, and Amazon. I occasionally buy direct from AAM (mostly for the front axle).

Eaton 8.6 GM 10b complete assembly #19659-010 (these only come in one offset 2.73 thru 5.38). The literature says this requires special carrier bearings but, that is for pre-99 vehicles, and doesn't apply to the H3.
Eaton Locking Mechanism Service Kit #29305-00S (this is the ramp plates & pin springs kit)
Eaton Gear & Pin Service Kit #29296-00S (this is the internal spider gears, side gears, cross shaft, and locking pins)
US Standard Gear 8.6 10b bearing kit #SPZ-58012 or ZBKGM8.6 (this is a complete diff rebuild kit with bearings, pinion seal, crush sleave, pinion nut, and cover gasket) DOES NOT FIT 09-UP!
US Standard Gear 8.6 10b bearing kit #SPZ-58013 or ZBKGM8.6B (this is a complete diff rebuild kit with bearings, pinion seal, crush sleave, pinion nut, and cover gasket) DOES NOT FIT 08-DOWN!
Timken rear axle shaft seal #TMK-4762N (this is seal on the end of the axle tubes)
EBC Greenie brake pads #EBC-DP61760
Wagner parking brake pads #Z908
MAX rear crossdrilled & slotted rotors #SY158222
Lube Locker re-usable 10-bolt cover gasket #LLR-G850

The US Standard bearing kits are what I normally use when rebuilding 8.6 axles. However, if you are doing a re-gear or a new locker install...you can buy "master" kits which come with ring gear bolts and shims for the pinion depth and backlash adjustments. Not all H3 rear axles are the same...2009 and 2010 models have a larger inner pinion bearing that requires a different kit.

Lastly...there are many small parts that can be bought direct from AAM if needed:
http://www.demandaam.com/axle-results?vm=GM&q=8.6"+10+Bolt+-+Rear+Axle

 

[4speedfunk]

MORE GM 10-bolt INFO...

I did not mention gearsets but, you can get 8.5/8.6 gears from many sources. I use USA Gear and Yukon regularly. These are traditional "five-cut" gears and use the normal .006"-.010" backlash. However, when using AAM or GM gears, they are made with a "two-cut" process that require a tighter backlash tolerance...usually .003"-.006". You may see 10-bolt axles listed as 8.5/8.6 but, they all use the same gearsets. You may also see them referred to as "GM Corp" or "AAM" but, they are the same basic axle. There is no difference between front and rear 10-bolt gears or carriers...all are low-pinion standard rotation. However early (pre-90) versions used 28-spline shafts, and later ones (including the H3) use 30-spline shafts. The pinion seal was redesigned in 99 to a two-piece style.

The carrier offset change occurs at the 2.73 ratio....so for all practical purposes, everyone on this forum will use a standard 3-4 series carrier (which includes the Eaton E-locker). If for some reason you are using a 2-series offset carrier (2.56, 2.41, 2.36 ratios)...you can buy thick-cut gears in lower ratios that allow you to run them on your 2-series carrier. If you plan to run 4.88's, 5.13's, or 5.38's...you will need to do some creative grinding on the teeth to get the cross-pin installed. The ring gear bolts are LH thread! Bolts should be replaced when doing a gear swap.

Some 80s-90s 2WD trucks, police cars, and taxi cabs use a HD version that has bolt-in axles (no C-clips)...but I have only ever seen these with a 5 on 5" 2WD bolt-pattern (92-97 Caprice LTZ/Impala SS and also the 90's-era 454 SS pick-up). Not sure if a 4WD GM truck (with a 6-lug pattern) ever came with anything but c-clip 10-bolts.

 

[H32NV]

Ordered all part, hoping I don't need a new pinion and ring gear. When I took the cover off and looked in August it seemed fine...although the locker was not working then...

MORE GM 10-bolt INFO...

I did not mention gearsets but, you can get 8.5/8.6 gears from many sources. I use USA Gear and Yukon regularly. These are traditional "five-cut" gears and use the normal .006"-.010" backlash. However, when using AAM or GM gears, they are made with a "two-cut" process that require a tighter backlash tolerance...usually .003"-.006". You may see 10-bolt axles listed as 8.5/8.6 but, they all use the same gearsets. You may also see them referred to as "GM Corp" or "AAM" but, they are the same basic axle. There is no difference between front and rear 10-bolt gears or carriers...all are low-pinion standard rotation. However early (pre-90) versions used 28-spline shafts, and later ones (including the H3) use 30-spline shafts. The pinion seal was redesigned in 99 to a two-piece style.

The carrier offset change occurs at the 2.73 ratio....so for all practical purposes, everyone on this forum will use a standard 3-4 series carrier (which includes the Eaton E-locker). If for some reason you are using a 2-series offset carrier (2.56, 2.41, 2.36 ratios)...you can buy thick-cut gears in lower ratios that allow you to run them on your 2-series carrier. If you plan to run 4.88's, 5.13's, or 5.38's...you will need to do some creative grinding on the teeth to get the cross-pin installed. The ring gear bolts are LH thread! Bolts should be replaced when doing a gear swap.

Some 80s-90s 2WD trucks, police cars, and taxi cabs use a HD version that has bolt-in axles (no C-clips)...but I have only ever seen these with a 5 on 5" 2WD bolt-pattern (92-97 Caprice LTZ/Impala SS and also the 90's-era 454 SS pick-up). Not sure if a 4WD GM truck (with a 6-lug pattern) ever came with anything but c-clip 10-bolts.

 

[mjferencak]

Those are some pretty pics. I just spent 5 mins staring at them.

 

[4speedfunk]

That actually looks pretty good but, I see some metallic dust lurking deep in the valleys on the spider gears (between the teeth)...a good indication something ain't right. Mine looked similar and I thought all was good until I took the carrier out and got a closer look. Once you remove the cross pin and c-clips, you can pull the axles out...the spiders and side gears will come out (fall out onto the floor). The drivers-side side gear is the one you need to look at. Specifically the backside of it. There are six oval slots in the backside...look for rounded off corners on the slots. This is where the locking pins engage, and they will be rounded off as well. Mine side gear was completely broken, and you could tell it was broken from the pins meshing into the backside. However it broke so hard that it took a tooth off the front side of it as well. I was so greasy at the time, I did not take a pic of the back side or the pins but, here's a photo of the front...


After ordering and waiting on the gear kit....I took it further apart and found that one of the locker engagement "ramps" was broken into three separate pieces! That dohinky looked like this...


You can clearly see that it snapped right where the three ball bearings sit. Obviously something went completely haywire inside the locker...probably from the racheting that occurs when you change direction with an E-locker. I try to be as gentile as I can but...thats wheelin! (if you wanna play...you gotta pay). This ramp piece was part of another kit...so I had to wait some more. Once everything arrived, I replaced all the internals and followed it up with a new set of bearings, crush sleeve, and pinion seal. My ring & pinion was fine. I also took the opportunity to refresh the brakes and axle tube seals since I already had it drained down.

P.S.
BTW...Mileage is 49,600. I run Mobile 1 full-synth 75-90 with a tube of Kendall posi additive. Gears are Yukon 5.13s. Bearings are Koyo (USA). Ironically, the latest Timken bearings are Chinese.

P.S.S.
I forgot to mention...this locker was fully functional and worked great even with rounded off pins and a broken ramp. I tore it apart only due to the whining at highway speeds.