I have a 99 a4wd eb expy , the a4wd makes a popping noise almost like its jumping in and out of gear. It all started when I had a tire rod end go out and i hit a gaurdrail at about 40 mph . I had the tire rod end and the bearing replaced , Im thinking that it may be coming from the cv shaft but am unsure now because when it is put into 4h the popping stops . It only does this under accelleration and not at all in 4h . Can someone help , I cant afford another trip to the mechanic I just gave him 18hundred bucks to install new engine and am pretty mechanical just need to know where to start.

 

Lets start off by clarifying the terms. You do not have All Wheel Drive, you have Automatic 4 Wheel Drive (A4WD on the switch).

The difference is that awd denotes a center differential, which these trucks do not have. When the automatic 4wd engages it is the same as manually selecting 4H. If the popping and grinding is not present in 4H, then you likely have a problem with the speed sensors or engagement motor.

If it was a CV on one of the axles, it should make the same bad noises when turning in A4WD and 4H.

One good possibility is tire size differences. They need to all be the same for the A4WD system to work properly, same size and same tread depth. If not you will have the computer trying to engage 4WD when it shouldn't and that could cause the problem you have.

 

First make sure you're in A4WD, then remove fuse #104 from the under hood power box and go for a test drive. Let us know if the problem still happens (or doesn't) when you're in A4WD with the fuse removed.

 

Good thing I kept my mouth shut. Having never pulled the fuse I though it was #14. That would not have worked

Can you still select 4H with the fuse out?

 

First time for everything!

No, without the fuse in there is no power to operate the shift motor or the front clutch.

 

Thanks guys will do some investigating and let ya know

 

O.K. I pulled fuse 104 and no more popping!!! This leads me to believe that I'm having problems with the 1) transfer case 2) shifter motor , I should probably change and service the fluid in transfer case , and check for proper operation of the shift motor but when in 4h or 4l all seems to be working fine . any suggestions on what else to check . also Im going to rotate the tires to see if it was what Greeny said . I realllly appreciate all the help and knowledge this forum has and the willingness of the members to share that vast knowledge of the inner workings of the all mighty expy . (Im not wothy)

 

After doing some searches , I think that my symptoms sound alot like the chain is coming apart in the transfer case (ugh!!!!!) after spending all that money on a new engine just figures . can a somewhat handy guy rebuild this himself without paying a huge bill .

 

Is there a way to check the chain without removing the transfer case ?

 

In a word, "NO". the place where the chain usually hangs up is on the inside on one of the pins/axles for the planetary gears. Pm your email address and I'll send pics of the parts from my son's t-case.
You can do the repair yourself and you will likely need a chain and the planetary gear and possibly the viscous clutch assembly.

 

You can do the job yourself as it is pretty straight forward. You will need the chain a planetary, and possibly the viscous clutch assembly. Provided that your problem is the same as my son's was. I would get the parts before starting from a parts store like Advance as you can return what you don't use if they are still saleable.

 

Can you also send me the pics of the parts and if you happen to know the prices and from where you have bought.......

 

Moose we went through this at the end of July and early August. Go back to this link and read again.
Most of the parts are available from Advance or AutoZone and maybe all of them.

Ford Truck Enthusiasts Forums - View Profile: moose_j9

 

I'd first look into the possibility of different sized tires. First thing to try is swapping the front and rear tires on ONE SIDE ONLY. Than drive it with the fuse back in and see if there's any difference. If there is, then the issue is the tires.

 

I checked the tires and the front passenger side (spare) has alot more tread than drivers side , I will try to swap to rear and see if thats my problem (I really hope ) thanks agian all