so i'm gonna change my tranny and transfer fluid before i move tomorrow. the repair manual says to put it in 4wd for a few miles to warm up the transfer case fluid before draining it. so i start driving it and then when i'm on a good straight section of road, i pull the stick back to engage 4wd and all i hear is grinding (like when you attempt to put the tranny into a gear without the clutch and you're moving). i tried pushing the clutch in while doing it and it did it again. neutral, same thing. so i start to slow down and keep trying. down to about 1-2 mph and it's still doing it. when it's at a dead stop, it engages 4wd perfectly without a problem, like it always has. i've always been able to do it (just as the original OWNER'S manual says) by simply pulling the t-case stick back, not letting the gas up or anything. (however, normally when i've done it "on the fly", i let up the gas and hit the clutch and i could move it from 2 to 4wd with my pinky finger). but i've NEVER had to stop first? what happened to my on-the-fly shifting? that'll suck if i find myself in a sudden pinch this winter if i hit a drift of snow or something and i can't engage 4wd without stopping first. any ideas?

 

do you have AUTO hubs, manual or ADD?

 

Ok this is simple

Your hubs are not engaged. I am guessing that you have manual hubs.

Your manual hubs are either unlocked or your add or auto hubs are not engaging.

What is happening is that when your driving, your rear shhaft and transfer and tranny are all spinning while the disengaged from driveshaft is sitting still. When you got to put it in 4wd, that dead still front shaft is grinding against the moving transfer gears. When you stop it engages becaus everything is stopped.

Shifting on the fly works because the front wheels turn the front shaft at the same speed that the rear wheels turn the rear shaft.

pretty simple, just get out and lock the hubs.

 

wow. my face is red. i knew exactly everything that you said and it just completely slipped my mind that i have my hubs unlocked when not offroading and it's not the winter. um, forget i asked, k? haha. :pat: i think i'm getting retarded in my old age.

 

Well, it looks like you figured it out (or replied to the post) while I was typing this. In any case, I'll leave the paragraph below in just for info.

Truth be told, your front driveshaft and rear driveshaft don't work at exactly the same speed. They are far enough off in fact that you are supposed to use 4wd on dry pavement too much, if at all. You'll tank a diff. Because your front and rear drive mechanism are a tad off from each other, they need a synchro to make up for the difference. Some gear oils, especially Mobil 1 synthetic gear oil, that are rated GL5 will cause your synchros to stop working.

Regards,
Joel

 

I could be wrong, but I think the front and rear are only different when turning.

 

you won't blow a diff because of being in 4wd on dry pavement...you could in theory mess up the transfer case.

i'd be worried about damage to the t-case from trying to slam it into gear with the hubs unlocked while driving, takes a good deal of force to overcome the inertia of the front driveshaft, differential and axle shafts...

 

well, needless to say, my retardedness was only temporary and i only tried a few times. everything is good to go.

besides, it's a toyota. how could it ever possibly break? haha. jk.