Here's some gasoline for the fire!
Techies can read this. Newbies please skip to the next post, you'll only drive your local parts guy nuts if you try to talk to him about it.
Here goes: There's no such thing as "4cyl" and "V6" R&P.
"Uhhhhhh, say what Beavis?"
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.
- SPH gears will fit V6 housings if you add a lot of inner pinion bearing shims. Precision Gear avoids having to use so many shims by offering an aftermarket LPH gearset for V6 housings.
- '88-'95 V6 housings must obviously use V6 inner pinion bearings, so there's no confusion here.
- Carrier bearings aren't an issue here either, just R&P. You need 4cyl carrier bearings for 4cyl housings and V6 carrier bearings for V6 housings regardless of year.
So what good does this do anyone? Say you have some used LPH gears collecting dust because you didn't think you could use them in your 4cyl housing. They're even the ratio you want, like the V6-only factory 4.56 or a set of Precision LPH gears (any ratio) your buddy traded you for a six-pack. Take your bad self over to Toyota and order a '86-'95 4cyl inner pinion bearing, and you're in business!
Note: The above does not apply to the somewhat rare "3rd type" of R&P, the factory 4.88's. These can only be used in the factory 4.88 housing. This housing is different than all the others, and won't accept ANY aftermarket R&P or factory gears of any other ratio. If you have one of these 3rds, it will be that way forever. Please don't sell this 3rd (or god-forbid an empty housing) to anyone without fully explaining what they are getting, think of the potential frustration.