Topic: Changing the fluid in a dual case setup - Question

[blackdiamond]

I have a dual case setup with an Inchworm crawl box and will be changing the oil in it either tonight or later this week.  In the past, I've always filled through the front shifter until it came out the fill hole on the rear case.  I did this slowly to make sure to give it time for the oil to pass into the rear case.  My question is if I know about how much fluid needs to go in, shouldn't I be able to just fill it through the rear case and let it flow into the front case?  I'm not planning to remove the cross member so I won't be pulling the plug on the front case so I'm expect that it should take about 2 quarts plus a little.

Any thoughts?  I really don't feel like pulling all the shifters apart.

[yotatough]

you can fill it from either one, it should hold 3 quarts. even if you only pull the rear drain it will still drain the front box also at the same time, its all the same.

[blackdiamond [OP]]

you can fill it from either one, it should hold 3 quarts. even if you only pull the rear drain it will still drain the front box also at the same time, its all the same.

I'm pretty sure the front case will hold a little since the bearing isn't right at the bottom of the case.  A friend of mine just did this and didn't get as much as he expected into the case so he jacked up the back end and forced it to take more.  After discussing it with me he drained about a half quart from the expected total which indicates that it's holding about a half quart in the front case.

[blackdiamond [OP]]

Also, I thought it about something like 1.7 qts in the rear and 1 qt in the front for a total of about 2.7 quarts? 

[46&2]

After draining it I always fill the rear case until it pours out the fill hole, then pull the shifter and add more to the front. I used to just fill the rear case, drive around the driveway in 4wd, and recheck it, but that took too much time. Just filling from the rear never seems to get enough into the front case in my experience. I don't even run the plastic trim around the tranny/front case shifter so it takes about a minute to remove my shifter.

[blackdiamond [OP]]

I pulled the plugs on the transmission and t-case tonight and both were perfectly full and the little bit of oil that came out looked brand new so I aborted the mission and called it done.

I finally got the soft top put back of in anticipation of the upcoming Moab trip and it sure is easier to put on once you remember how it works.

[toyota castine]

Nice

[superkaliguy]

what weight oil or gear oil should i use? so  it doesn't matter which shifter i fill, but i need to pull of the drain plug just to make sure its full? kinda got lost, this is a noobie question

[blackdiamond [OP]]

what weight oil or gear oil should i use? so  it doesn't matter which shifter i fill, but i need to pull of the drain plug just to make sure its full? kinda got lost, this is a noobie question

I think the best method is to fill through the forward shifter until it drains out the fill plug on the back of the rear case.  Don't overfill because it can take a while for the fluid to pass from the front to the rear case, but it worked well for me in the past.  It should be about 2.7 quarts total.

[blackdiamond [OP]]

Either 75w-90 or 80w-90 should work fine.

[superkaliguy]

Thank you

[79coyotefrg]

ive always dumped 1 qt into the crawl box and 2 qts into the rear then checked.  it almost always worked to within a few cups.