Want to see what you guys think on this subject. Couple of things, one is why do we need to run atf+4 and not something like even 10-30 motor oil or some similar weight hydraulic fluid. And two I'm in process of messing with my leaky tcase from rear output seal. I changed it for the 3rd time now, but this time I changed tail bushing too, it got deformed up on install at the oil drain grove, at least driveshaft feels tight now. It did have a drip after first trip but now it's seems ok. Some residual fluid from lubing it on install maybe.

So I just want to flush tcase for some reason.

Question is what do you think would happen if anything  if I mix matched different trans fluids for let's say 10miles just to flush it out and go back to atf+4. I'm thinking it should be just fine as tcase is not a transmission and doesn't really need all the additives to run right. Plus I have this fluid on the shelf that I'll never use and figured it would be an honor for it to go out this way. Older models called for atf+3 and dextron3 and I heard of some that tried hydraulic oil before. 

Sure I can just drain what I have in there and put new stuff in and call it a day or go get some cheap atf+4 and flush with that but what fun would that be. This is what I got sitting around some of it for last 15 years or so. No rush take your time 

I say use it up and flush that sucker. You will need to drive in 4x4 or jack up all 4 and let it run in 4x4 for a few minutes. If you don't the chain wont turn and slosh the fluid around. Just driving around in 4x2 won't stir it up. I used ATF+4 for years but now use Motorcraft 5w/30 synthetic blend, same as my Ford Escape engine oil.

 

 

 

 

14 minutes ago, NIsaacs said:

You will need to drive in 4x4 or jack up all 4 and let it run in 4x4 for a few minutes.

I got that cable posi lock on the front I can put tcase in 4x4 and leave the cable out, it should do it I would think. The cad won't be engaged, but front shaft will spin. Thanks for the confidence  I figured this whole atf4 is warranty thing, not that it doesn't work, just feel that in something like tcase it should be simple.

If I remember right you also use 15w40 in your nv5600?

Okay, the disconnect is cool, I wish I had one at times. Yes, I use 15w/40 in my NV5600, I change it and all gear boxes every 36k miles.

3 minutes ago, NIsaacs said:

Yes, I use 15w/40 in my NV5600,

How many miles have you put on it so far with 15w40, you obviously like it or you wouldn't be doing it. Any particular brand of oil, high on tbn 

Nevermind on oil brand, it's right there on the 5 gallon pail 

I'm going to bed now been a long day

Only thing I can think of is maybe the old fluid wouldn't be compatible with the seals but I seriously doubt it.

Look what came out flushing, hope it doesn't spring a leak. 

Quarter is just for reference I don't hide my money there from my wife