[Wheelie_Pete]

So I scored some craigslist gold tonight in the form of an unopened Yukon master install kit for an 8" 4cyl third ~$50. :smokin:

Now what I'm wondering is why does YUKON have two different part #'s for 8" 4cyl master install kits:

YK T8-A (14117) "Yukon Master Overhaul Kit for '85 and older Toyota 8.0 differential"

YK T8-B (14118) "Yukon Master Overhaul Kit for '86 and newer Toyota 8.0" differential"

It's not the V6, that has it's own kit (YK-TV6) I've got thirds from all years laying around the shop so using the kit won't be a problem, but I was operating under the belief that 79-95 (8") 4cyl thirds were all setup on the same bearings. Someone know EXACTLY why they (Yukon) have different kits?

 

[Wheelie_Pete]

Shit, nevermind, I found the answer: http://www.pirate4x4.com/forum/showpost.php?p=1478223&postcount=73

From Drew's post above:

"There are actually two types of R&P, let's call them "LPH" (Long Pinion Head) and "SPH" (Short Pinion Head)."

- '79-'85 rigs have SPH gears and a "thick" inner pinion bearing designed for the 4cyl housing. All aftermarket "4cyl" R&P and inner pinion bearings are identical to these factory parts, that way the same part numbers will fit all '79-'95 four-cylinder rigs.

- '86-'95 four-cylinder and V6 rigs ALL come with LPH gears. However, to use LPH gears in a four-cylinder housing you MUST use the "thin" '86-'95 factory Toyota four-cylinder inner pinion bearing. If you use a "thick" aftermarket bearing (or a factory '79-'85 bearing) the pinion will be too deep into the mesh and won't work."

 

[Wheelie_Pete]

So if I'm reading that right, I'm fine for putting aftermarket 5.29 gears into an '87 thirdmember using the YK Y8-A install kit that has the fat inner bearing because according to Drew's post "'79-'85 rigs have SPH gears and a "thick" inner pinion bearing designed for the 4cyl housing. All aftermarket "4cyl" R&P and inner pinion bearings are identical to these factory parts, that way the same part numbers will fit all '79-'95 four-cylinder rigs.

I guess the YK T8-B is for rebuilding using factory LPH gears on the 86-95 thrids? Is this correct or did I fawk up the reading of this?