Thump while shifting into 4H

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Feb 1, 2011 | 10:58 AM

W7PSK

Thread Starter

Tuned

Joined: Dec 2010

Posts: 348

Likes: 14

From: Everett. Washington

Thump while shifting into 4H

Anyone else notice a THUMP when shifting into 4H. Is this a normal sound or do I have an issue ? Hubs are on Auto.

Feb 1, 2011 | 11:02 AM

fz1dave

Super Duty

Joined: Oct 2010

Posts: 2,525

Likes: 1

From: NW IN.

It's normal. At least I think it is... if it's not, I have the same problem.

Feb 1, 2011 | 11:05 AM

EpicCowlick

Post Fiend

Joined: Apr 2004

Posts: 5,158

Likes: 35

From: North of Salt Lake City

Every Ford I have ever had has made that same engagement thump. It never caused problems on the Expedition or the Excursion. I just make sure I'm not actually spinning the wheels when I turn on 4X4.

Feb 1, 2011 | 11:05 AM

2000silverbullet

Lead Driver

Joined: Aug 2004

Posts: 5,326

Likes: 18

From: Gilbert

Mine does it too. I haven't tried it yet with the hubs locked to see if the same thing occurs, but it's definitely louder than the ESOF system in my 2000 F-250.

Quote:

Originally Posted by EpicCowlick

I just make sure I'm not actually spinning the wheels when I turn on 4X4.

You'll get the check 4x4 system warning if they're spinning. I got stuck in a driveway last weekend, wheels hadn't completely stopped on the ice and threw the switch, warning received and no 4x4. Threw the switch back to 2wd, then back to 4H and it worked fine.

Feb 1, 2011 | 12:00 PM

Byram

Posting Guru

Joined: Jul 2001

Posts: 1,126

Likes: 2

From: Austin, TX USA

Mine doesn't seem to be any louder than my 2001... but I usualy turn it on while going slow - so that might be the difference.

"I just make sure I'm not actually spinning the wheels when I turn on 4X4."

I did that on my '01 the first couple of weeks that I owned it - it was the first ESOF i had ever owned... Needless to say -- I never did THAT again!!

Feb 1, 2011 | 12:15 PM

rickatic

Postmaster

Joined: Apr 2009

Posts: 3,839

Likes: 2

The thump is louder now that the truck is so quiet.

Feb 1, 2011 | 12:52 PM

jfritz_drfritz

Mountain Pass

Joined: Dec 2009

Posts: 224

Likes: 7

From: Regina, Saskatchewan

Does anyone know what the actual mechanism is inside the transfer case that spins the front drive shaft up to speed to synchronize with the front hubs or is it just a primitive "bang -whack"?

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Feb 1, 2011 | 01:54 PM

djjoshuad

Posting Guru

Joined: Apr 2004

Posts: 1,399

Likes: 1

From: Corinth, TX

I would think it's a synchro just like in a manual transmission... but I really don't know.

I can say that there is no noticeable sound from my truck when shifting into 4H. In today's ice, I have shifted in and out a few times. shifts into 4H have mostly been while stopped, but I did a couple at about 5 mph. shifts out have been mostly at speeds under 10mph. no clunks, thuds, or other noises. and it's definitely shifting in and out. I park in a parking garage here at work, and I don't want to wear my brand new tires out, so I shift out of 4H when I get onto the dry pavement inside the garage. smooth every time.