4wd thunk when I stop

For the past few days it has been snowing here in colorado so i put on my 4wd instead of 2wd and when I was turning out of the gas station today and stopped at the light, my car jerked forward slightly and i heard a thump/thunk coming from the back of my 2008 tacoma truck. I pulled over to see if someone hit me, but they did not so im concerned that something is not working properly.

Should i be concerned or is this just them unlocking or something? When I turn the wheel when im stopped or turning, it feels like it locks up and i have to push on the gas a bit more to make the vehicle move. Not knowing anything about cars/trucks scares me. Do I need to take the vehicle in or is this normal?

 

Not sure about your knock during braking , but the binding when turning in 4wd is a normal side effect .

 

Welcome to TW and the world of Four Wheel Drive... The quick answers to your questions are:

When you turn the dial from H2 to H4 there is a 'THUNK' that might occur right away or a few seconds later as you roll ahead from a stop. It can be a bit loud and scary if it is your first time using 4WD in this truck.

When you return to 2WD, it also can be heard (and felt) as a 'thunk'... quite normal.

I suggest you only use 4WD when your tires are spinning instead of moving you (snow, ice, mud, sand) and never on dry pavement... unless driving straight for periodic parts lubrication as the manual advises (if you can't find dirt to drive on).

Steering takes more effort in 4WD, since the front and back axles are locked together at the transfer case and slipping of tires would need to occur when turning. Go back to H2 if you are driving very slowly into a parking spot that requires extra steering effort. Go into 4WD for more traction to get unstuck or keep from getting stuck. H4 (4WD HIGH) is shift-on-the-fly so can be done stopped or up to 60 mph... as soon as you need more traction (less slipping).

Just FYI... L4 is LOW RANGE 4WD and that is for extra power to climb steep grades or power through deep mud or snow. To get into (and out of) L4, you must come to a stop and put the transmission (if an automatic) into N (Neutral) not P (Park), then turn the dial while depressing it at the same time.

Yes, this is in the owners manual and the card in your sun visor... but sometimes hearing it in a different way helps, right?

 

I have only used 4wd when the roads are icy. I used 4wd before so i wasnt sure if the "thunk" was normal. I always use 2wd until recentlly when the roads were gettting icy/snowy. I normally use 2wd to drive everywhere and 4wd when there is snow on the ground.

thanks for the advice and all. I appreciate it! :3