GM 14 Bolt Axle – Pilot or Straddle Bearing Information
GM 14 Bolt Axle – Pilot or Straddle Bearing Information


This is the rear diff on my 1982 GMC 1 ton. It’s a 14 bolt full floater. When I pulled the cover off the other day to change
the fluid…. This vehicle is new to me…. I discovered some bearing parts down here in the bottom on the magnet. That was pretty scary…. but what I discovered was pilot bearing or also called the straddle bearing that
fits on the tip of the pinion…. its way back up in here…. that’s the
actual tip of the pinion… I’ve already removed the
damaged bearing outside/race but all that all those bearing
rollers were gone just leaving the race. They fell down
in here down to the bottom and attached to this
magnet. I’m going to be replacing that bearing right now. In order to get the pinion carrier out, you need to remove the drive shaft. This the front of the driveshaft on my truck. Just make sure that you mark the shaft and on the truck side so that you can
get it aligned exactly the same way when you reassemble. That will help prevent vibration when you put it back together.
This is the other side of the drive shaft, the pinion side. Same thing here, just mark it so you get it back in the same spot
rotationally and then remove the four bolts on the retainers and then you should be able to slide the drive shaft forward and get the drive shaft out. It’s pretty
straight forward. After you get the driveshaft off this is what it looks like. Don’t mess with the center pinion nut. For our purposes we don’t want to take
that off and mess with all of the shim set up and everything like that.
Just remove the six carrier bolts around the outside. Make sure you mark the carrier and housing with a marker or a punch so you know
which direction to get back in. There are also either shims or a shim between the carrier and housing. Here’s one on mine. It’s very
important to to get that back in there when you put
it back together. Don’t bend it and make sure
everything is clean. Here is the pinion and pinion carrier. You can see the main bearings are in there and the
tip of the pinion is where the new bearing goes. Here’s the new bearing. It slips on there pretty easily. You do you install it in the rear end
first before putting the pinion in. Here is a shot with the pinion and carrier
removed. I have also already taken the old bearing race. It’s hard to see but at the
9 o’clock and 3 o’clock positions there are some cut-outs and that helps you bang out that old
bearing race. It is a little difficult but I did this with the axle still in the truck. It just takes little bit of time. I used a socket extension to get back
there and knock it out. Here’s the pinion side. Again, I’ve got the old race already taken out but you can see what it looks like with no
bearing. The new pilot bearing does install and
come out through the pinion side of the rear end. Here’s what the new pilot bearing looks like after it’s installed. When you tap it in, make sure and use something that drives it from the outer race. You don’t
want to be pounding on the rollers and make sure you get to seated all the way. This is what it should look like after you get it all back together. A brand new bearing in there to support the tip of the pinion.

14 thoughts on “GM 14 Bolt Axle – Pilot or Straddle Bearing Information”

  1. Francois Kuchinka says:

    Is that a g80 jw

  2. John says:

    Is that rear end listed as a G80 in the glovebox of the vehicle???

  3. nathan herrmann says:

    thank you for this vid, have to do it tomorrow.

  4. Ken Jones says:

    thanks 1st  vid ive found on this just helped me out 100%

  5. Ken Jones says:

    Where did u pick up ur parts

  6. Shane Tow says:

    does any one know the torque specs for the bolts for the differential

  7. Jeffrey Riggs says:

    i just tore mine apart. seems when i put a detroit in, I didnt do things right. never worked on one of these before and didnt adjust the gear mesh correctly. i chewed the teeth off all the way around the ring gear.. ughhhh
    check it out..
    https://ck5.com/forums/threads/so-they-say-14bff-with-detroit-is-bomb-proof-well.328280/

  8. Thanos says:

    They say stay away from the 80's version of the 14 bolt and look for the newer ones with the better pinion bearing.

  9. Jim Bo says:

    Awesome video.

  10. Suzanne texiera says:

    Thank you for making this video … my husband and I drained the fluid in his pumpkin today found the bearings just like you going to attempt this same thing wish us luck 🙂 only found 7 bearing chunks and the ring extremely glad our seal leaked and he decided to drain the rear fluid

  11. Robert Allen says:

    My same bearing went out. Unfortunately it wore a deep groove into the shaft so I have to do it all.

  12. Luis Montes says:

    What’s the bearing number and where did you get it ?

  13. Topdog Mechanic says:

    What symptoms did you have

  14. Max Mazur says:

    I got the rollers of the bearing out but i cant get the race out. How did you get the race out?

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