EB55

To all-I've got a 2013 FX4 had it brand new since 11-2013 27000mi. Got about 2 inches of snow tonight with more on the way. Put my truck in 4H tonight when I left work; didn't need it but haven't put in in 4x4 mode for a while so I thought I would engage it on my way home. When I engage the 4 wheel drive, I let off the gas, turn the switch, wait until it engages then off I go. Everything was OK tonight until someone swerved in front of me. I hit the brakes hard, and the whole back end of my truck felt like it jumped off the ground. WTF i'm thinking. So I tried some more hard braking and man the back end felt like it was leaving the ground. Now this was on a paved road, no potholes no bumps just snow.


Pulled into my driveway, left the truck running, and looked under front and back to see if there was anything obvious. Nothing, but I heard a loud moaning sound from the engine compartment. Opened the hood to see if I could pinpoint this sound, then it quit. After dinner took it out again and same thing was happening with the back end. Now I hearing something sounds like it's rattling in the front end. No idea what's going on.


Couple of things: E-locker was not engaged; first thing I checked. I have been driving 4x4s since 1970 in mud, snow, up and down mountains and never had anything like this happen. And I did a search but wasn't able to come up with anything similar to what I'm experiencing. I'm calling my local dealership tomorrow but would like to see if anybody on the forum has any thoughts about this.


Thanks


Tim

Toddman38

iTrader: (5)

Best ro take it by the dealer, maybe get lucky and they fix it! Maybe...

Never heard of that issue before, though...

EB55

Me either. Truck is stock, and have never had any issues with the 4 wheel drive. First problem I've had with this truck-been very impressed so far. I hate dealing with warranty issues.

MEZERR

I also have a 2013 FX4. I was just out dinking around in my subdivision, and I notice the exact same thing as you.

- In 4x4, when braking hard on a snow packed road, the rear end bounces, kinda violently. It seems to bounce when the rear tire locks up then releases (abs)
- At the same time, I can hear a rattle or clinking noise in the front. Take it out of 4x4 and no bouncing and no rattle.

Let me know if dealer finds anything.

MEZERR

Now that I think about it... I'm sure the problem happens when both front tires, or both rear tires momentarily lock-up when braking hard. When this happens, since the rear axle can't spin freely of the front axle (because in 4x4) this causes the front axle to momentarily lock up as well (or vice versa). This on and off binding seems to be causing some noise.

RajunKajun59

Almost sounds like the ABS in the front and rear are out of sync. Might just be a normal thing. ABS and TC pulsing breaks to stop the truck and keep it straight, something is bound to not sync right.

EB55

Haven't gotten into the dealer yet because of work but several observations. Light braking while in 4x4 everything seems to work fine-no bucking at all. In 2 wheel no problems at all with hard braking-very smooth. I am going to wait until we get some snow to take it in to the dealer so they can drive it and see what is happening. Probably won't be until late February or March-I have a tax business and don't get any break at all until then.

Masi1926

Too many nanny controls fighting each other, possibly.
I'll take the abs and the e-locker, but I wish they would've left the traction control to the sedans.

dkushner

I've noticed the same thing on both trucks I've owned, an '02 Tundra and my '13 F-150. I think that it's just a characteristic of trucks with rear leaf springs.

MEZERR

The truck brakes fine in 2WD