Cant seem to decode axle code

[Aaron N.S.]

I picked up a 8.8 out of a 99. All I have is the axle tag, and I looked at the FAQ's list of codes and I don't see any that match what the tag says. Is there more then 1 tag on the axle? Am I just a dolt and can't see it?


here's how I read it from the top left

S354S

Bottom right to left

7.3 88 8M21

 

[Spitfire1975]

looks like a 3.73 ratio (open), 8.8 ring gear (obviously)

 

[Spitfire1975]

door code 96?

edit. Sorry. Didn't read close enough.

 

[Aaron N.S.]

looks like a 3.73 ratio (open), 8.8 ring gear (obviously)

thats what I was thinking. My only hi-cup was the example shows the tag showing the complete ratio (IE) 3 73 and this one shows a 7.3 ??

door tag 96??? what do you mean? I didn't see the truck it was pulled from, I was told it was a 99, It was free so I can't complain

 

[Spitfire1975]

Yeah. I didn't read close enough before I asked what the door code was. Can't get it without the truck. It looks like part of the tag print is simply corroded away. The only ratio they had that ended with a 3 was the 3.73, a common ratio. It may be a limited slip, but would put my money on an open.

 

[Aaron N.S.]

Hmmm. I Like the open Diff, as kinda hoping for a taller ratio, something around the 4.10 range. Oh well. can you convert from a 28s to a 31s?

 

[Spitfire1975]

I am not the best to ask about tire sizes. Biggest I go is 235 75's. From what I have heard others say, a 3.73 ratio with 31's is just fine.

 

[Spitfire1975]

You'll know if it is an open or not the first time you spin the tires on gravel, or look inside for the clutch packs ( I believe L/S diffs have clutch packs.....again, I am not the best source on that).

 

[Aaron N.S.]

I am not the best to ask about tire sizes. Biggest I go is 235 75's. From what I have heard others say, a 3.73 ratio with 31's is just fine.

I was referring to spline count, not tire size lol, I suppose I could have been more clear.

 

[Spitfire1975]

LOL. Told you I wasn't the best resource!

 

[Yellowsplash]

No, you cannot "convert" to 31-spline axleshafts using the ranger axle housing.

The only way to get the 31-spline axleshafts would be to replace the whole axle with one from either an FX4 Level II or an Explorer.

 

[4x4junkie]

No, you cannot "convert" to 31-spline axleshafts using the ranger axle housing.

Yes you can. You just have to use custom-made 31 spline shafts that have the smaller bearing journals on them. Of course this would leave you unable to source replacement shafts at a junkyard however.

 

[Aaron N.S.]

Yes you can. You just have to use custom-made 31 spline shafts that have the smaller bearing journals on them. Of course this would leave you unable to source replacement shafts at a junkyard however.

wouldn't that weaken the shaft? would it be easier, stronger to have thiner bearings in the shaft to accommodate the thicker shaft? is that even an option?

 

[4x4junkie]

No... Why would it weaken it? It's the same size as before, but has a 31 spline end on it instead of a 28 (infact aftermarket shafts are often a 1541 alloy rather than the 1040 steel the factory shafts are, so it'd actually still be stronger).

It would be weaker than a factory 31 spline shaft though, if that's what you meant.
Explorer shafts using thinner bearings is a no go due to them being longer.

 

[superds]

Axle Codes
The following lists the gear ratios on axles.

• KA — No ratio, Electric
• 84 — 3.45, non-limited slip
• 86 — 3.73, non-limited slip
• 87 — 4.10, non-limited slip
• 89 — 4.56, non-limited slip
• F6 — 3.73, limited slip
• F7 — 4.10, limited slip
• 95 — 3.55, non-limited slip
• R5 — 3.55, limited slip
• 96 — 3.73, non-limited slip
• R6 — 3.73, limited slip

These are all the axle codes available for a Ranger in 1999. The only ones that end in 3 are 3.73, so that's what I would put money on.

To determine whether it's a limited slip: rotate one side (drum and wheel studs, etc.) of the axle, does the other side rotate in the same direction? If so it's most likely a limited slip differential. If it rotates in the opposite direction then it's probably open.

As far as the ratio, you can tell absolutely by rotating the axle shaft (by looking at the drum again) one full revolution and making a note of the movement of the pinion. How many times does the pinion make a full revolution? 4.1 or 3.73? Or some other number? The difference in the number of revolutions should be fairly obvious if you make a mark at the top and follow it as it goes around. This number will show you your gear ratio.