Trying to identify rear axle

Tiny
FGR8FRK
  • MEMBER
  • 1993 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 226,000 MILES
What does XPF K254 stamped on the right axle tube mean? It's an open unit and was thinking of installing a lsd. But want to get the right one.
Monday, November 1st, 2021 AT 3:03 PM

5 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
I am attaching the decoding chart that you will need to figure this out.

I am not finding the axle code of XPF at all as this was a Canadian vehicle, so I don't have any records of their codes.

If you are able to find what XPF stands for then that will solve it for you.

The K254 means it was a Canadian axle made on the 254th day of that year, most likely 1992.

However, you are able to get a pretty good idea what the axle ratio is by doing the following.

Since you have an open rear differential, you need to lift only one wheel off the ground so that the drive shaft will spin.

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

Then mark the tire at 12 o'clock. Then put a tape mark on the bottom of the drive shaft. Then turn the tire two full revolutions and count the number of turns the driver shaft makes.

This will give you your ratio. If the drive shaft spins 8 and a half times, then you have the 8.50 rear axle.

You have the corporate axle and not the dana so you will find your options below, but it appears it is any of them except the 11-inch rear which was the dana.

Otherwise, you are going to have to remove the cover and count the teeth of the ring and pinion gear to find the ratio.

Please let us know if you have other questions. Thanks
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Monday, November 1st, 2021 AT 6:19 PM
Tiny
FGR8FRK
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I have the cover off and just counted teeth, it came out to a 3.42 ratio. I want to make it a LSD and am searching for a complete rear end but am wondering if I can just replace the carrier and use the original ring and pinion.
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Monday, November 1st, 2021 AT 6:36 PM
Tiny
KASEKENNY
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Okay, great.

If you want to switch this to a limited slip differential, then yes you would just need the carrier that has a limited slip set up. Then you just swap the ring gear over.

Here is a video that we have on a newer Chevrolet that will help with this.

https://www.youtube.com/watch?v=zarxKsspr3s

Also, check out this video that is on this exact issue. In fact, this is on basically the same truck as yours and you may recognize the guys if you watched the weekend car shows.

https://youtu.be/kDXSNqaT9Us

Let us know what other questions you have. Thanks
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Monday, November 1st, 2021 AT 6:54 PM
Tiny
FGR8FRK
  • MEMBER
  • 46 POSTS
So, I have a few options on LSD units now. Just finished cleaning brake hardware and backing plate and removed the leaking seals. Decided to reinstall the axles and check bearing play. Both sides have "Up and Down" play with the left side being worse, roughly.007/.009. Both axles look good with no pitting or grooves from the bearings. How much play is excessive? Also checked lash which was.013.
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Saturday, November 6th, 2021 AT 12:35 PM
Tiny
KASEKENNY
  • MECHANIC
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Great job. I am attaching the spec for backlash which you are higher than the spec for new gears which is what I would follow. Even if you didn't have any noise, I would suggest dropping it just to avoid any clunking.

As for the axles, you are talking about movement that you are finding at the outer axle bearings which are number 15 in the attached below? If so, then you should not have any up and downplay so they need to be replaced.
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Saturday, November 6th, 2021 AT 2:44 PM

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