Drove my 1989 4Runner all last winter without a hiccup.. stored it for roughly 5 months and just pulled it out the other day because winter is here, yet again!! booo

Anyways, it drives fine while it's in 2high..
I lock the hubs and get back in and fire it into 4high and then it just seems like it's hesitating. It's fine when I'm coasting but as soon as I touch the gas, it feels like the whole front end it vibrating slightly.. just seems like something isn't right.
If I put it back into 2high.. with the hubs still locked.. it seems fine. 4lo also seems fine.. so it's just in 4hi!

Common fix to this? Diff oil is topped up.. it's a little thick.. but that shouldn't matter.

Any help would be greatly appreciated guys.. I'm stumped.

 

i have the exact same problem - bad manual hubs maybe?

 

Change the diff fluid. Hows the u joints in the front drive shaft?? any play in it?? any slop or play in the cv shafts? cv boots torn and need grease and to be fixed?? Remember you are turning A LOT more parts in 4 hi at higher speeds then you are in 2wd. So some vibration is to be expected. You won't feel as much vibration in 4lo because of a lack of speed.

just some stuff to look for

 

You can get some vibration from the front driveshaft getting worn out. If you only get the vibration at higher speeds with the hubs locked you might want to check it....

I noticed when mine went out I didnt notice it much at low speeds and when i wasnt on the gas, then all of a sudden it got really really bad.

Also check and make sure your front diff mounts are tight and the rubber is not worn out.