Where to put level for fluid changes?

Should I level off of the frame, rocker, or door frame or where for fluid changes? I'm getting slightly different readings from all of those different points.

 

Generally, I put the fluid amount specified in the owner manual for oil with a new filter. Personally, I am not going to do my own transmission or differential, would let a shop do those.

 

Use level ground. Do you think the lube techs are putting a bubble gauge on the car to see if its level when they are checking the oil? Nope. Do you think they consider you have a lift or leveling kit and compensate for that? Nope again. Off the lift and on the ground/ garage floor.
Like mentioned above, fill it with the quantity that is listed in the manual and check it again when its on flat ground. Same with the tranny, diffs and what ever else fluid you are doing.

 

The frame itself? That would be my guess.

 

That's what I was thinking but I wanted to make sure that they didn't factor in The rake. Normally I wouldn't care but I'm trying to do custom ramps. I have about a 2 ft drop on my driveway and my garage floors about a 1nch drop so I thought I would Factor it in while I have an opportunity to get it right.

 

One thing to keep in mind is that the stock “nose down” rake is largely because of looks (the rear arches are higher than front relative to lower line of the body. The frame itself is not as raked as it looks. Play around with this side-on photo, and you can see a lot of rake is “built in” to the body lines and relative height of wheel arches. Which is one reason that too leveled could actually be true negative rake.



Anyway, I have mine leveled with a 2.5/1.5 lift. So far have only changed the rear diff oil. I put a fluid amount according to factory specs, and I recall nothing coming out the fill hole. So I added more until it did (I hope that’s what you are supposed to do, because that’s how Ive always read you’re supposed to fill them till it starts coming out).

Anyway, you’d think it would have started overflowing with less fluid since the fill as at the back of the pumpkin, and the new rake (on the frame) flattened out the angle compared to stock, but it didnt overflow at all. I remember adding a fair bit more than the amount required by the book.

Not sure where the fill holes are for the front diff and TC, and how that would be affected by the angle changes.

 

You did it right. Fill until it dribbles out.

But explain to me how the lift of your cab effected the rear diff? Did you change the pinion angle? Are you running custom length lower control arms on the rear? Was the nose jacked when you filled it?
But yes, the front and center will change by a small amount as they are mounted to the chassis, unlike the rear which is independent of the chassis ( underslung if you will...).

 

Thanks for the confirmation! As I get older, sometimes I end up doubting what I thought I knew. Whoa, didn’t mean that to be all “philosophical”, but it works that way as well

As for the lift, I should have clarified. I installed a dobinsons suspension lift, so yeah, the frame is no longer at the same angle relative to the ground (or the line between center point of front and rear hubs, that would be the better reference).

It’s a small angle change, and probably doesnt matter for fill amounts…unless it does matter, which I think is the OPs concern. I’m curious myself, since you hear reports of front diff drops causing angle changes which dont allow it to be filled enough before the reaching the fill hole.

i dont know enough about how “clocking” changes when you view the rear axle from the side. Do the control arms “clock” the solid-axle to keep pinion angle the same, or does the axle stay in the same relative clock position, or half-way in between? And Im not even sure if taller springs would be like the axle is lower on the stroke (do taller springs make more stroke?

I suppose knowing these details would help to know if that fill plug would be angled the same, or tipping down a bit after a suspension lift, resulting in reduced capacity. I just figured it would have tipped down, but now I see there are lots of factors involved.


OP…. You probably could have refilled all your diffs, and driven 100k miles to verify it wasnt damaging to the diffs in the time it took for me to think of this response.

 

Geez, now Im seriously really fighting the urge to just go outside, slide under the 4runner with a flashlight and try to puzzle out how all those control arms work the rear axle. My neighbors already wonder why Im under there so much to begin with. Guarantee none of them wanna buy a 4runner after seeing me putz around under it so much.

 

I probably overfilled my front diff since it has a diff drop. I doubt that a few extra ounces of oil would cause a problem unlike the sealed transmission since the differentials are vented.

 

So is the consensus that the frame needs to be level plus or minus 2 inches??

 

not sure about that question, but it would be interesting to put a jack while the drain is open, then jack it up a little bit after you fill it. That way you could see the effect…if any drips out, or if you can put a bit more in after jacking.