1991 Ford Explorer 4x4. Knocking with a temperature increase.

[Walkaway0911]

91 Explorer 4x4 (manual)

The good: It runs great in 2wd so at least I can drive it

The bad: When I engage the 4wd all is well; Even if I just set in one spot with it engaged the vehicle is fine. Once I decide to give it some gas after about 15ft it makes a hard thomp...after 10ft later another hard thomp...The engine temperature also rises when I do this...

Where would you start at??? I am new to repairing vehicles so videos are a big plus! Also if you tell me what I need to fix or look at (In Detail) would be greatly appreciated.

Future plans for my vehicle: Just bought it today for $1000...I want to lift it up 4+ inches and put some 42 inch swampers on it. I also want to take off the corny step ups on the side of it and maybe MAYBE get a cheap paint job on it. No hurry I have another vehicle this is all just a fun project!

 

[BigRondo]

Welcome aboard!!

You have mistakenly posted in the Stock 2011 + Ford Explorer Discussion Sub Forum.

I think you meant to post in the Stock 1991 - 1994 Explorers Sub Forum.

Here is the link to the Stock 1991 - 1994 Explorers Sub Forum: http://www.explorerforum.com/forums/forumdisplay.php?f=99

I'll see if i can get a Moderator to move it for you.

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 91-94 section.

 

[Walkaway0911]

Tnx

Thank you for moving me to the correct location; Looks like I have found a good forum home!!! :yelexp:

 

[FIND]

A hard thomp?

Knocking is an engine noise, it makes a sound like a small hammer banging on your engine. It indicates detonation, which can be caused by a variety of circumstances, such as too lean a mixture, too low of octane fuel or a couple other issues.

 

[Walkaway0911]

Yes but remember this is only when I am in 4WD and only after moving the vehicle roughly 10-15ft does it even make this knocking sound. 2wd the ENGINE works great.

 

[Walkaway0911]

Also I want to note that I smelt something like a burning smell when I put it in 4wd and it made the thump. I was reading on this forum about it possible being U-Joints binding up??? Yes/No ???

 

[FIND]

Is it knocking, or are you getting a bang noise in 4wd that only happens at certain times. Knocking is something that happens regularly at the same speed as the engine is turning. It sounds just like when an engine runs out of gas.

This is an example of knocking:


Anywho... going by what you are talking about, I recommend you jack up the front end to get the wheels off the ground, then spin the front driveshaft with the transfer case in 2wd. Watch to see if both front wheels start turning. Grab the axles on each side and check to see if there is excessive play by shaking them.

 

[MrShorty]

I'm with Find -- what you are describing sounds more like a drivetrain binding in 4wd. This is a basic part time system that locks the front and rear together at the transfer case. When I have seen this, something is different about the front and rear that causes binding in the drivetrain. In addition to inspecting the axles, I'd look for something different between the front and rear (different size tires, different gear ratios, etc.).

 

[ernzo]

Sounds like Torque Wind-up....front end is locked in 4x4 to the rears and if the tires are not pretty much EXACTLY the same, the front axle will get out of sync with the back axle. When it gets too "wound up" it shifts and clunks and starts the whole process again...10-15 feet is about right....

I have that right now.. and I just replaced the rears with new tires, exactly the same as the fronts / size, make everything...except the fronts are NOT new and are about1/2 worn and that is enough...