Maint req light after rear/front diff fluid change?

I changed both front and rear diff fluid as well as transfer case and now my maint required light is on? I also notice a wierd whining or high pitched humming coming from somewhere under the front at full throttle. Does not sound like the LSD. Could anyting with chaning these fluids cause my maint light to come on? Its not the check engine light. And what is that sound im hearing? I checked all levels and after a short drive needed to add a tiny bit then it started seeping so i know they are full.

Rear 75-90dino oil 3 quarts with 4 oz lsd additive
Front 75-90mobile 1 (1.6 qt) sythetic oil
Transfer case 75-90mobile 1 (1.1) synthetic oil

 

Ok so the light is for an oil change, I already have the oil and filter for that as well.

Anybody know about the noise I'm hearing? Its a winding noise that happens at full throttle, as the rpms go higher the winding sound matches and sounds like its winding up with the rpms.

 

FULL throttle? Did you fill your diffs? Broken or empty gears are loud under load.
engine RPM not wheel speed related right? Alternator? imagination? thick oil? used 5 or 10 -30? water pump?
If its under the hood grab a 3 foot length of fuel hose, stick it in your ear and listen for it.

 

I used 75-90 mobile 1 synthetic LS gear oil. The sound is not related to wheel speed, its only under load as im giving full throttle from 3000rpms and up. Its not there when I drive like a grandpa. The oil levels are all full

Is it more likely to be coming from front diff? Does the front diff even spin when not in 4wd? Or could it be the transfer case?

 

So if its not the transfer case then the front diff should be the culprit?

 

Not if none of this is wheel related. He said RPM and load I thought.

Put 50 weight in a crank case or over fill and it can whine like a bitch.