A while back, I was starting to spin in 2wd on some snow so I put it into 4 low. I started to go again and something went "boom" and started grinding. I put the tranny in reverse and same thing. I switched transfer into 2 hi and it was normal. Put it into 4 hi, normal, back into 4 low, normal. So obviously it wasn't in right. Ever since that occurred, however, I have noticed that often times going down the road in 4WD, my indicator light will start blinking. It only occurs if I have my foot on the gas. If I release so that there is no longer torque being put to the wheels, the light stops blinking and stays solid. Itll work for a while, and then blink again. It doesn't always do this, but Im worried that its a sign of worse things to come. 4WD works perfectly fine though, so its not a real big issue as of now. I went through some pretty deep snow a couple weeks ago and was really leaning on the 4Wd to get me out and it never had issues. Is it possible that its just my switch that senses if 4wd is in or not? As far as I know, there is 2 sensors. One on the transfer case which I assume makes the front 4WD actuator kick in. The indicator light I assume is hooked up the 4wd actuator because it does not come on when I shift into 4WD, but instead when the actuator kicks in. Anybody got any ideas? Im thinking my 4wd actuator has something wrong with it or rather a beat up collar that locks the axle shafts together. I just pulled the right axle the other day and it looks fine so IDK. Seems to point towards whatever CONTROLS the actuator.

 

Could be weak vacuum, or, a leak somewhere in the system.

There is just the vacuum switch on the t-case, the switch for the light is indeed on the front axle. Inboard side of the cad housing. Check connections and such first, then check vacuum. See if you find anything.

 

Alright, but why would it kick back in if I let off the gas if its a vacuum leak? I mean, I thought the vacuum would increase if the engine was at a higher RPM. I don't mean to argue here, just confused on the subject. I seen some oil in the throttle body yesterday which I've heard can point to a leaking plenum and therefore losing vacuum pressure. However, its not excessive and I know some oil is going to be in the filter housing/throttle body because it comes through as vapor and collects on the sides. Thanks for the advice btw.

 

your highest vaccum is at zero throttle,im assuming there is a vaccum reasavor under the hood somewere to retain vaccum at higher rpms..

 

Ah, ok. That makes much more sense to a vacuum leak problem. Now comes the issue of finding it...maybe I should start with checking sensor if all connections are good.