Hello all.

Did some hunting around on here - not sure if I'm finding what I need to answer this question:

I have inherited some problems with my new-old truck:

1989 pickup, V6, with 4.88 gears and a spooled rear differential.

The spooled rear is chewing up the tires, and has got to go. I want to put an open diff back into it.

I know, I know... spool to open diff, WHY? Good question, for another time.

I have been told, and do understand: my best option is a Detroit locker for a V6 Toyota in the rear, since compatibility/sizing won't be an issue; However, money IS an issue, and a stock carrier is a much cheaper option.

My dilemma is that, while understanding the basic principles of what I'm dealing with, I have no idea of compatibility.

If the stock 1989 rear differential was just converted to 4.88 gears, would that mean that just the ring and pinion were swapped?

If so, would that mean the stock carrier from a truck of that generation (which is the only part I need to replace) should theoretically fit, even though it's been re-geared?

If I understand correctly: spider gears and differential pinion gears don't care about the gear ratio, the carrier simply has to fit the ring gear and have the correct number of splines for the axle(s)?

I really hope this wasn't answered in an "everything about identifying your diff" thread that I missed, or a "Which diff in what truck" thread...

By all means, point me in the right direction...

I'm hoping to learn which parts will fit, so that I can find a diff carrier BEFORE I have to open up the differential and start pulling things out. I have a potential buyer for the spool, and potential sources for the carrier and related hardware, but can't commit without some clue as to viability.

Hopefully this makes sense.

If this gets answered, I will happily edit and condense this thread into a "So you have a mystery diff" thread and post some pictures/how to stuff. Suggestions for a helpful title also welcome.

Thanks all.

 

If I understand correctly, the factory made 4.88 ring gears are a different thickness than other factory gears are, so they require a diff housing unto themselves that cannot accomodate gears of any other ratio. The carriers are supposed to be the same as other factory carriers.

It is possible too, that you have a regular type diff housing and aftermarket 4.88s' were installed.

This would mean that you might be able to put in alternate ratio gears, if you wish to.

In any case, common Toyota carriers should fit in your housing.

You will likely have to open it up to see what you've really got.

Edited to correct factual mistakes.

Have a look at this:

http://home.4x4wire.com/erik/diffs/

 

Beauty, thanks guys.

Actually, I think someone linked me to that same diff identification page before on the BC4x4 forums but the link wasn't right, so I couldn't read it.

That's a perfect page.

Turns out (by identifying it via photograph) that I have the standard "V6/Turbo" diff housing, which would mean that the 4.88:1 ring and pinion set that have been installed are aftermarket.

I found the build page on Pirate 4x4 from the guy that originally built up this truck. He doesn't mention the rear specifically, but it's either the Yukon gear set that he bought for the front but used on the rear when he opted for an ARB air locker in the front OR a different set of aftermarket 4.88s if the front wouldn't fit with shims.

I guess in either case it means that I have aftermarket gears, so a standard 4-pinion rear carrier should work.

It looks like I CANNOT use a 4-cylinder carrier though, without (expensive) carrier bearing adapters, which is too bad since it probably limits my options.

I'm starting to think that with the cost of an aftermarket carrier loaded with gears, and the general availability of stock open V6 diff carriers... maybe an autolocker isn't such a bad option for the cost?

 

Auto lunchbox lockers still requires the use of the stock case/carrier. If you can't find a stock 4 pinion open case for your V6 3rd then feel free to contact me. I have a spare and I can ship it Fedex ground to your zip code.
Read off your stamped numbers on the ring gear and I'll tell you if those 488 gears are OEM or aftermarket.
Ken

 

Solid group of people on here. Thanks guys!

Ok, so that's good to know, because I was essentially told that a Detroit would NOT require the carrier, making it a simple option as opposed to finding a complete open carrier with the gears in it.

Also, I should probably update my user info: I'm in BC, so I'm not sure how shipping would be all the way up here...?

Once I get this old girl back to my home and get a chance to lift it up again, I'll come back with the stamped numbers- Much appreciated!

Had a wheel bearing come apart on the highway, somehow wrecked a bunch of other stuff.

Also discovered a shot center bearing on the driveshaft, caliper mounting bolt stripped, the remote starter is acting up, there's an elecrical fault somewhere in the dash I think, the wiper arm stripped, the key broke in half, the driver door lock actuator seems to have broken, and the blower motor tanked. Also has a sort of ominous ticking up front- Ah... the old trucks. I might never learn...

She looked so good before I signed the papers! Hah.

Suffice it to say: Gonna have to put my diff troubles on 'simmer' until some of these other day to day driveability issues are sorted, I think.

Thank you guys a ton for the input so far though!

 

You are correct mysteryfish... A Detroit locker unit IS the complete gear carrier and no Toyota carrier is required.

Only the so-called 'lunchbox lockers' require the use of a stock gear carrier to accept the locking unit inside.