Can a 4x4 be driven in 2WD without front diff oil?

[ShooterMcGavin]

I just ordered oil to change out the fluids in all my gear cases (front/rear diffs and tcase). Yes, I did many searches to find out how much oil I need total. I got mixed results... 5, 6, 7, 8 qts. I avoided asking here because I know the popular response would be "search" (and that would be pretty good advice).

I have a rear e-locker. My latest search told me 4.9 qts total (1.1, 1.2, 2.9 for the different cases), so I bought 5 qts. ETA: It seems my math was off, for whatever reason, because I now see that 1.1 + 1.2 + 2.9 = 5.2. I will need at least 1 more qt. Back to the original question...

I just ordered oil from online and now I'm worried that I didn't get enough to do the whole job. I am wondering, if I didn't get enough, can I at least replace the rear diff and t-case fluid and run the front dry while I order more. Of course, only using 2WD. I will only know if I didn't get enough when I drain the front and don't have enough to fill it back up, if my searches gave me the wrong amount. I didn't want to get more oil than I needed because it was $16 per qt.

 

[ChildrenOfBodom]

No, the front diff still rotates with wheel movement, the axles are directly connected. The disengagement point is near the pinion flange (where the front driveshaft bolts to the front differential), meaning that input from the transfer case is disconnected. When you click the transfer case lever into 4H, the ADD switch near the pinion flange makes the connection.

Lets say you had manual locking hubs. You could disengage the axles from the hubs at each front wheel, meaning that the rotation of the tires would not rotate the axles or diff. With 4WD (ADD switch) disengaged, the transfer case input will not rotate the front diff either.

Stock 4wd 3rd gens cannot be driven with no gear oil in the front diff.

 

[02SE]

No. The side gears in the front diff spin anytime the vehicle is moving in a stock A.D.D. setup. Running for any length of time without gear oil in there, will cause premature wear, and/or failure.

 

[lude and rude]

a way to combat this only if in extreme cases... is remove the axle shafts from the bells. this would mean that the bell is still holding the wheel bearing hub in place and your in 2wd mod (literally). leave the bell in the diff so it doesnt get crude in it. this is a lot of work to run around without oil in the diff, (NOT SAYING YOU SHOULD DO THIS BUT SO OTHERS CAN UNDERSTAND THAT ITS POSSIBLE). buddy of mine had to do this two different times, once when he snapped his axle shaft off roading (one side with out axle shaft but left the bells in place), second time was when he blew up his diff and was having it worked on he took the diff completely out an left bells in so he could drive around town for a couple weeks until he had money to fix the issue.

but to answer your question... no because your front axles are rotating all the time. jack the front up and spin a tire you will see the issue

 

[ShooterMcGavin]

Ok, thanks! I won't do it

I did more searching... Please correct me if I am wrong, but here is what I have found...
front diff: 1.2qt
T-case: 1.1qt
rear diff with e-locker: 2.75qt

Is that right?

 

[lude and rude]

http://www.toyota.com/t3Portal/document/om/OM35694U/pdf/omsource/1997om/974runne/sect8/81.pdf

your numbers look right, check out this link. its for a 97 4runner

 

[Desert Fox]

Maybe this is a stupid question (it is late and I am enjoying a Captain) Why would you drain the gear oil if you don't have enough to fill it?

If you don't drain it you don't have a problem. you don't have to do all the diffs at the same time.

What am I missing here?

 

[ShooterMcGavin]

Maybe this is a stupid question (it is late and I am enjoying a Captain) Why would you drain the gear oil if you don't have enough to fill it?

If you don't drain it you don't have a problem. you don't have to do all the diffs at the same time.

What am I missing here?

I've been having trouble finding out the exact fill amounts for each gear case, so I won't know if I'm coming up short until I drain and then attempt to fill all of them. If I order 5 qts and it turns out that the total capacity is 5.5 qts, then one of the gear cases will not be filled until I order more oil and wait.

Thanks for that, L&R!

 

[nevada]

I've been having trouble finding out the exact fill amounts for each gear case, so I won't know if I'm coming up short until I drain and then attempt to fill all of them. If I order 5 qts and it turns out that the total capacity is 5.5 qts, then one of the gear cases will not be filled until I order more oil and wait.

Thanks for that, L&R!

if it ends up being 1/2 quart low, it will be fine until you can get some more.

 

[ShooterMcGavin]

if it ends up being 1/2 quart low, it will be fine until you can get some more.

I would assume so, but I don't want to have to guess. I mean, what if it is 1 qt low (especially when one case only holds 1.1 qts)? I don't know where the threshold is for "just enough"

 

[02SE]

No, the front diff still rotates with wheel movement, the axles are directly connected. The disengagement point is near the pinion flange (where the front driveshaft bolts to the front differential), meaning that input from the transfer case is disconnected.

Actually, only the side (spider) gears within the differential turn whenever the vehicle is moving in 2wd, They are driven by the left (driver-side) CV-axle.

The axle disconnect is on the right (passenger) side of the differential housing. As seen in the diagram below.

OP, I think it would be foolish to drive with only a partially full front diff housing. I would wait to change it until you have enough gear oil to complete the job.

 

[Robb235]

Why not just change your diff fluid in the parking lot of an autoparts store like I did?

Need more oil? Walk in and buy another quart.

 

[larrylegend]

You could always just change the rear and xfer case, then leave the front until your new oil comes in. That way you know for sure you have enough. The change cycle wouldn't be off by that much if your new oil comes in next week.

 

[JBurt]

I think a lot of people are missing the point. He said he didn't want to buy more oil if he didn't need it. If you are ordering it it makes it harder to return. I'd rather have some left over, and I think you should have more than you think you need especially if you've never done it before, but that is just me. Carry on.

 

[ShooterMcGavin]

I think a lot of people are missing the point. He said he didn't want to buy more oil if he didn't need it. If you are ordering it it makes it harder to return. I'd rather have some left over, and I think you should have more than you think you need especially if you've never done it before, but that is just me. Carry on.

Exactly. The parts stores around me don't carry the syn oil I want to use, so I need to order it. I don't mind buying an extra quart but, at $16 each, I don't want to have much more than that. I definitely won't be driving it with low diff oil. Thanks all.