To fix the unfixable

[Nasanieru]

Hey Guys and Gals,

New to the forum...and hoping for miracles. Sorry for the added pressure. I am having a problem that two different dealers and a shop that starts with a blank, blank, das.
The issue is this, I have a 99 Expedition EB 236,500 miles. Automatic AW4D, 4WD, 4WL. When starting up the SUV in the morning It runs awesome. Motor, Transmission, 4WD. I have to drive 65 miles to work, interstate driving. When I reach where Im going and it starts when slowing down on the off ramp. The last couple of feet before I stop I hear and feel this loud thump come from what I would guess and feel would be the transfer case. Starting to drive around the town It thumps every time I stop and if I shifting speeds it will thump with the transition.
The 4WD at this time feels like it is bunching up. The whole vehicle hops around corners, grinds and the like. Finally get to the parking lot, The SUV sits all day long. Come outside to go home, the SUV is perfect again.

I have heard everything from fuel pump overheating to transfer case to the vehicle is fine, and it's normal. I have had most of the fluids changed in the vehicle 4 or 5 times. And been reassured that the fluids are full.

I love this truck and am in the process of fixing it up and upgrading alot. But, I can't start changing things If I don't have a dependable base to start from. I am sorry to ask this of you, but I need help and only have a certain amount of money. Can't just go throwing it at everyone of my ideas of what the problem could be.
Thank you for your time, and I hope that everyone has better ideas then me of what the problem could be.

Nathan

 

[tonydiv]

If you weren't in MN, I'd suggest removing the front driveshaft to see if it solves the issue. But I assume that you need 4wd this time of year.

Does it still do it in 4 hi?

 

[eddiemoney]

Did you check the u-joints? Basic stuff first

 

[Nasanieru]

thanks DIV and Money for the reply. I personaly have not checked the u-joints, I had assumed that the shops I had gone to would do all those checks. But, I mite have to take things into my own hands and get dirty. As for TONYDIV, I was worried to shift it into 4HI because I didnt know if I would get it back to 4AWD. Thanks for taking the weather into effect, Had almost 2 feet already. But, I will check and get back to the post.

 

[FordandPolaris]

Have you done any brake work lately?

 

[Nasanieru]

F&P Have not done any brake work. To me they have performed the same through out the day of driving. I should also mention this, when I drive the vehicle all day in town under the speed of 35 it doesn't matter how long I drive the SUV works great. It seems to only happen when driving long periods at speeds greater then 35mph. Nice to here from a fellow viking.

 

[stamp11127]

I looked in my service manual.... unless you see something that looks obviously wrong your going to have your hands full troubleshooting this puppy. That transfer case isn't the old style set of gears. Now monitored by the GEM - I'd look to see if there are any GEM DTC's to start. There are sensors on both drive shafts monitoring the speed of each & used to run the internals. Just the GEM alone has over 50 tests for the transfer case.

So them telling you it is normal....I don't think so

 

[Nasanieru]

Thanks stamp, I have been trying to look under the vehicle at the drivetrain and it all looks french. I know motors...When it comes to what moves the vehicle I have no clue. What does a bad u-joint feel like? Is there a special way to remove the front drive shaft? Wish I new someone that could help me out with the technical stuff, so I could learn what to do. oh yeah, and not pay an arm and a leg...lol. You Guys are awesome...please keep it up the more things that you can suggest the more stuff I can cross off.

Nathan