I want to change the fluid in my transfer case, but I won't have any real long stretches of straight road I could run in 4x4 to get the fluid warmed up.

I have a manual t-case and I'm wondering if I could put the t-case in 4x4 high, but leave the hubs disengaged.

Would it work to heat the fluid up and would it damage anything if I did that?

 

I changed mine relatively cool. Parked it on a slight incline and it all dripped out in a timely manner.

 

I did mine cold on an incline also. Worked well Pete.

 

I took mine out for about 3 miles or so with the hubs unlocked but in 4x4 and then I drained it and filled it with 2 quarts of syn. mercon-V, old fluid was dark at 115.000, I will be changing on a regular basis now that I seen that. I do believe if I remember, its a 10 mm metric allen wrench, I had to borrow because I didn't have one in that size.

 

FWIW, it wont make much difference, running in 2wd, vs 4wd, as far as heating the oil. In both situations, the case/input gets most of its heat from the transmission, and the fluid just circulates. Enableing 4wd, only allows the drive chain, to be engaged. Nothing really causes heat, in a transfercase. And it is actually filled with ATF, which flows out pretty well. If your that concerned about getting ALL the old fluid out, start in the morning, after letting it sit over night. That way any of the pumped, or slung oil is at the bottom of the case, put a pan under it, and let it drain. And if your really going crazy, let it sit an hour.

When I did mine, the truck was up to temp (just drove it) and I drained it, and then refilled. IMO its really no big deal, to make sure you get every ounce of old fluid out. Our transfercases have no clutches, or wear items in them. Only occaisional services they need, are oil seals, and rarely, you can stretch your chain enough to be an issue. But Ive only even done that on smaller cases, havent heard of it in a NV 271 or 273, unless it was from a dedicated sled puller.