Hi all
I have a 99 expedition eb AWD Last week it started binding up and grinding when turning it feels like it is kicking in to 4x4 and turning on dry pavement everytime i turn the wheel the rear wheels sweal like they are locked up took it to a shop and they are not sure they say you can hear it while driving but when it is on the life they hear nothing. but you can sure feel it on the ground. any ideas how to trouble shoot this problem they want to start by draining the fluids in front and rear diff and\or tranfercase to see if they can find any major metal shavings or such to try and locate the problem. i have read all kind of possible solutions from rear diff clutches, speed sensors,4x4 clutch motor, 4x4 messed up. Any ideas out there where to start trouble shooting?

Thank you in advance
Dom

 

So you feel the front wheels engaging, but the rear wheels make the noise when turning? Are your tires worn?

 

Thanks for the response Bussard

I cant really feel the front engage but never noticed it before but the rear wheels are deffinatly slipping or jumping i watch them jump while i had the wife turn and give a little gas and the tires are getting pretty worn out. the last few thing done. just put on new shocks maybe 3000 miles ago changed tranfer case fluid rear and front diff fluids as well the truck has 157000 miles on it if this helps any

Thanks again
Dom

 

did you put friction modifier in the rear? Assuming you have the limited slip rear of course.

Sounds to me like it's acting pretty normal, when you try to turn a tight turn the front and rear track a different circle so the transfer case thinks it's slipping and locks up the transfer case. But if you didn't put friction modifier in the rear it may be exaggerating the normal "hopping" that you'd get because the rear end can't slip like it should.

 

Thanks Pitrow for the reply Yep put friction modifier in the rear diff. no this is not the normal slip you feel when you make a tight tight turn. you dont even have to make a real tight turn for it to start jumping and sqealing. it is ok if it is just a slight turn but as you progress say turning on to a side street it starts to bind up

Thanks again for the reply
Dom

 

Dom,

For some unknown reason my front wheels were engaging when my selector switch was in A4WD (I could hear a droaning sound coming from the front end and feel a hop when making sharp turns). In lieu of pinpointing the problem, I merely pulled the fuse (inside engine compartment) that allows the transfer case to shift into 4wd. Later I installed a fused switch so I could engage 4wd from inside the cab in the event I need it. Some day I'll have the problem diagnosed, but I actually like the fact that my truck drives like a 2wd but still have 4wd at the flip of a switch.

I'd recommend you pull the 30a fuse and see if your problem subsides. FWIW, a couple common culprits that cause 4wd related problems include worn tires and stuck t-case shift motor.

 

Thanks Jim we tried the 30 a fuse and no Luck Still the same we also disconnected the shift motor to see and no change. so not sure where to go from here. the shop is going to check the tires out and measure them out so we will see. Do you think it can be locked up in 4x4hi or something?

Thanks again Jim

Dom

 

The shift motors on the transfer cases do go out quite frequently. However I 'think' that if that was the case you'd have the 4x4 light on the dash on. Maybe not though. Might be worthwhile trying a few circles in A4wd and 4HI and see if you notice a difference.

 

It sounds like rear differential. If pulling the fuse so the 4x4 would not ingage did not make a difference then I would look at the rear end. Most of time they start howling.

 

pitrow

Thanks again for the reply so far if it is in awd 4x4hi 4x4lo it still makes a groaning/grinding sound and bounces\binds up tried it with out the shift motor and still the same from what i got last night one of the front tire mesurements is off by 1/4 to 3/8 inch from what i read that may be the problem but with that said if this is the case what damage was caused by it will be the question. will have to keep investigating

Thanks again
Dom

 

Omahastro1
thank you for the help
here is what seems to be happening when going along the road i can seem to tell if it is groaning i have pretty knobby tires that make a lot of road noise but i do know when i start to turn i get a groaning sound and a real crappy turn feels like the truck only want to go strait once i finish the turn the groan continues for a for min then seems to go away. i am starting to think maybe it is just tires causing it to engage in to 4x4 to stop slipage it thinks is there i am thinking i will take my 04 expy and 99 to a tire shop and swap the wheels al long as the 04 is within mesurement specs and see if it helps i think that beats buying new tires to find out it is the rear diff or transfer case.

also is there any tests to tell if it is the rear diff or front for that matter?

Again thank you all so much for the help
Dom

 

Check to make sure the '04 lug pattern is the same as the '99....I think they're different.

 

My 99 4x4 does the exact same thing. I'm convinced that is why these trucks eat ball-joints. I am installing an "off-on" switch on the automatic 4x4 today. Hopefully, that will cure some of the problem.
You'll probably never get the rear-end to stop hopping and clunking. I've tried several rear dif lubes including adding Lucas oil posi additive, with no change. It's just something I've come to live with.........140K miles on mine BTW

 

I had not read this thread until today, but noticed my 2001 doing the same this past week. Of course it has been real cold, I had a brainy idea that may be the cause, than I also checked my tires and the rear looks like the tires have been hopping. I had a rear put in a few years back, so I wonder? I am also going to get new tires after the first of the year and see if this cures the illness. If it gets worse before hand I will take it in where I had the rear end put in and see if that is the issue after all.

Everything else mentioned did check on with mine also.

 

I tapped into the fuse box under the hood & replaced the bus fuse for the auto 4x4 with an inline fuse and a DPST switch. It has made a huge difference in tight space driving, like parking lots or garages. The truck doesn't hop anymore or make that horrible groaning noise from the front end. However, if I do want to engage the 4x4 I have one extra switch to mess with.........cheaper than a transfer case or transmission though.