1999 EB 5.4 4x4 weird issues

[josh1095]

first off hello.
i posted this in the ford-trucks forum and most guys were kind of puzzled. but still very helpful. anyway, i bought this truck for real cheap a few weeks ago. didnt care about 4wd but now i do! i found that the front driveshaft was missing lol. ordered a new one, knowing that i would soon find out why the previous owner disconnected it in the first place......

after installing i took it for a drive. at approx. 30mph i start hearing a groaning sound and it feels like 4wd is trying to kick in. it pulls to the right slightly and definitely feels like theres more resistance. back off the throttle and drop below 30, prob goes away.
in 4hi its very "bound" up, thats the best i can explain it. its jerking and pulling to the right. but it definitely has a heavy load, feels like im towing 5000lbs lol.
4lo engages and going in a straight line each wheel will alternately slip and jerk randomly. it DOES work however, i tested it on like a 40 degree hill today.
so i leave driveshaft in and pull fuse 104(tcase motor/tcase clutch power).
PROBLEM GONE. just like driving it without a front driveshaft...
i have verified the tcase motor is working properly. checked and even changed tcase fluid. checked both differentials etc.
another thing to note: b4 driveshaft was put in i could put it in 4lo or 4hi with no problems.
i took it to a tranny shop, guy did a few tests and drove it. came back very confused. he had no clear answers or suggestions. not very confidence inspiring.
btw, my tires are all the same brand and tread depth. even measured circumference
personally i think the chain/clutch/shift forks or something is fuked in the tcase. im sure im forgetting some details, but any help would be very much appreciated. thanks to all who look

 

[Thermo]

josh, I have something for you to try. With as much loading as you are seeing, something is probably going to get very hot. So, take the truck out to a gravel/dirt lot (or some dirt road) and put the truck in 4HI. Drive as fast as you safely can up to 55 mph and do that for 5-10 minutes. Now, stop the truck and crawl under it. Feel along the drivetrain. Concentrate on the output of the transfer case for the front driveshaft and the pinion bearing in the front differential. These should be warm, but you should still be able to put your hand on the components. If they are so hot that you can't put your hand there, you have located your problem. I would take a guess that you have a bad front differential pinion bearing or a bearing on the gear housing inside the front differential.

 

[JUST4FUN]

is the ABS working on the truck? the ABS sences slip in the wheels
( A4WD ) if this is not right then it will give you problems

 

[JUST4FUN]

does the front wheels and diff rotate all the way back to the t case? in a4wd/2wd?? i know the early ones had vacuume actvation that locked the wheels in

 

[josh1095]

abs is working. i even took out the abs fuse and tested. same problem.
the 99 has 4awd,4hi,4lo settings and has no vaccuum hubs or any actuators in the front.
thermo, i will test this out tomorrw morning if at all possible. thanks alot.
that said, would it still make sense that the front differnetial seems fine with fuse 104 out? even when turning and driving it makes no weird noises.
i will still test ur theory as its a good troubleshooting technique

edit: just thought of one problem with the front diff: the fact that it starts binding up at 30mph and up. the clutch in the tcase must be engaging. now why would that happen?

 

[josh1095]

thermo, i tried what you said. i had a tranny shop take it for a test drive. first thing the guy said was tcase problem!!! so i jumped underneath and felt both differeentials. they were warm the tcase almost burned my hand it was so hot. i was quoted 900 parts/labor to rebuild it. sounds a bit steep. i found a used one with 110k miles for 100 bucks locally. these arent common failure items on fords right? im thinking ill just do the job myself. the sensors seem to be the hardest part of the entire job. everything else is really straight forward.

 

[LameSuburbanDad]

my front tire would bind at idle speed, turned out to be a front axle.

lift it up and try to freewheel it, if any of the tires bind, that might be the issue.

 

[josh1095]

i wish it was just a bad bearing, god do i.....
after convincing myself and having a reputable tranny shop convince me, i hired someone today to swap out tcase. cost 500 for parts and labor. didnt fix the problem. i was pretty bummed.
this guy drove it with me and after i told him how i bought it with the front drive shaft missing he said it feels like the gear ratio in the fron or rear does not match. this makes perfect sense and all symptoms point to it. is there a way to identify the differential drive ratio? some stamp? where can i reference it? i read it should have 3.55 front and rear. most likely the previous owner swapped out the front or rear with a 3.31. thats why when i hit around 30mph it tries to even out the drive shaft speeds by engaging the tcase clutch. its also why 4hi binds so badly, its a 1.00 ratio in the tcase, 4lo is like a 2.2 ratio so the problems are less pronounced. its just costing so god damnd much. im going to jack it up on all 4s and have someone rotate the tire 360 and ill count the dshaft revolutions. do that for front and rear. thats GOT to be my problem.
im obsessing.....

 

[bigmatt207]

im having the same problem, if the gear ratios are the problem awesome, if not, this is what i was told. The front hubs are locked in through vacuum, if the vacuum resevoir or hubs are faulty the hubs will stay locked in all the time like its in 4lo. causing the binding when turning, if it is just the right side it is most likely something to do with your hub. I have pulled my resevoir and im just waiting for the new one to come in so i can put it in.pray. then see if it worked.

 

[jrjr]

is there a way to identify the differential drive ratio? some stamp? where can i reference it?

im going to jack it up on all 4s and have someone rotate the tire 360 and ill count the dshaft revolutions. do that for front and rear. thats GOT to be my problem.
im obsessing.....

Since gears can be changed and thus ratios, I wouldn't trust any markings anyway. Doing the rotation is the best way. then you know what you have.

 

[josh1095]

big matt: in 99 they got rid of the front vac hub system. they are permanently locked. it used a torque on demand system that, from what i gather is activated automatically when the pulses from the front and rear d shafts start to mismatch. it detects the rear slipping and engages clutch for front power. its an overly complicated system lol. i would be happy with 2hi and 4lo. straight forward and dirt simple. the truck was hit in the rear pass side and theres a good chance they replaced the rear from 3.55 to a 3.31. that would explain why my speedometer understates my actual speed. my real speed is 73 when the speedo indicates 65. only a lower rear end gear ratio can do that(or a larger diameter tire/wheel combo, but thats not the case). if people were honest this world would function so much better, all the previous owner had to do was tell the truth and it wouldve saved me 500 on a wild goose chase. ill report back when i run the numbers adn do the actual check this weekend.

 

[bigmatt207]

okay then maybe I'm F****d, i ordered a vacuum reservoir that i was told controls the front hubs, like you said maybe if people started being honest this world would function right, good luck and defiantly keep me updated, winter is coming and i really don't wanna have to mess with this after 8 inches of snow has fallen.
Thanks

 

[josh1095]

ok, ran the numbers. my stock factory gears are 373. front is 373 rear is....... a 331!!! those ****************************s right? i got a 373 rear today, installing it tomorrow. that was the problem all along. no wonder those mechanics had such a hard time troubleshooting the problem, who would ever put the wrong differential in??? they all cost the same price....

 

[BakerEdition]

KARMA guys....it will circle back and get those who need it, yes its a shame people cant tell the truth, but Josh look at the bright side, YOU da'man... meaning you figured it out and more than likely got a great deal and got a nice truck...and you learned things along the way...I always tell people that's "LIFE" banging on your hood....yeah the 500 would be better on a exhaust kit or a new programmer, but sometimes we have to learn life's lessons to become smarter....not trying to preach to you, but let you know we all have dents on our hoods....LOL...

 

[jrjr]

Prior owner may have done that for gas mileage.... who knows. Glad you got it sorted though. At least that transfer case shouldn't give you any issues!

 

[josh1095]

thanks baker, and after thinking about it, i can always earn another 500, ya kno? moneys, money. knowledge and experience? thats worth alot more. i will post back this afternoon when we finish and let ya'll know how it went and how the 4wd functions when theres 2 compatible diffs in the truck! lol

 

[BakerEdition]

Josh, your welcome....you can always try and sell the extra parts...the ones you can use keep for spares!