Front differential capacity based on hub type

[the_dingman]

So, I'm a manager at an AutoZone store, and our in-store system also lists specifications. I'm looking at changing the gear oil in my differentials soon, and wanted to see the capacities, and noticed something interesting. The front differential capacity is listed as different depending on whether automatic or manual locking hubs are installed.

Remembering my swap from auto to manual, the axle seals are not different, and no oil is supplied to the hubs. Apart from an incorrect spec (which is possible), I wonder what the difference is, could the differentials be different based on the hub choice?

 

[Hyde802]

They ADD actuator and slide collar need oil to lubricate, oil from the diff flows into the longside axle tube to do that, adding capacity.

Thats why you have to change the seal when switching to a non ADD tube.

Now if your actually talking about auto hubs, and not ADD, then I dont know...

 

[KidVermicious]

Apart from an incorrect spec (which is possible),

I'm voting for this. The Autozone system is wrong about several things on my '86, including whether it's a solid axle or IFS, and I've gotten no response from your Corporate about getting that corrected.

No offense, but I don't use Autozone any more.

 

[ajordan1975]

just fill untill oil comes out the fill hole. close it up and be done w/ it.

 

[helo-mech]

I'm not sure if you have the 22RE or the 3.0 but according to my owner’s manual for an 89 3.0 there are different capacities for the transmission fluid and t-case fluid based on whether or not it is a 5-Speed or Auto but the Front and Rear Diffs get 1.7 and 2.3 qts respectively. Only Auto and Manual Hubs were an option so the difference listed in the computer may be a mix up with an option for the ADD.

That being said, I don’t think anyone measures. Just "fill till it spills."

I have noticed most of the auto part stores have issues with keeping all the info configured correctly. It’s kind of like the Hayne’s Manuals, each are very helpful but you have to be able to read between the lines.

 

[fourwd1]

The non-ADD front axle (having auto or manual hubs) is 1.7 qts
The ADD front axle is 2.0 qts (increased capacity due to the ADD actuator)
Engine type makes no difference.

 

[helo-mech]

The non-ADD front axle (having auto or manual hubs) is 1.7 qts
The ADD front axle is 2.0 qts (increased capacity due to the ADD actuator)
Engine type makes no difference.

Not to get off topic here but I think this is what has a lot of people scratching their head when it comes to ADD and Auto/Manual Hubs. I know I still have to go look up crap every time I see the topic. It seems that people think their ADD is Auto cause that is what they are used to hearing. I think we need a good sticky for this topic.

 

[fourwd1]

Shouldn't need a sticky or anything else.
It's simple, older 4WD Toyotas (86-88 trucks/89 4Runners) have hubs (manual or auto) to lock the front axle into 4WD (NOTE - this is not to be confused with a locking differential, totally different thing).

In 89/90 Toyota went to the ADD system to lock the front axle (as did Jeep and most other IFS 4WD vehicles). No more hubs at all, they're replaced by drive flanges which permanently connect the wheel to the axle shaft. Locking is accomplished via a vacuum/electric/hydraulic actuator (depends on make) that couples/uncouples one axle shaft (left or right depending on make).
"Locking" the axle and engaging the t-case into 4WD all happens at the touch of a button or shift of one lever (known as Shift On the Fly, Torque On Demand, etc).

Much simpler for the growing demand of soccer moms for SUVs to get groceries at the mall.