[FullSizeBronco1990]

hello all, after finally fixing up the bronco and making it drivable once again i decided to go and test out the 4 wheel drive for the first time. unfortunately 4 wheels drive will not engage. i threw her in neutral and 4 lo and manually twisted the drive shaft. the drive shaft locked both times however i am not hearing the hubs click to let me know that they are locked. im not sure if vacuum has anything to do with it but it has good vacuum.

thanks

 

[89Heaver]

If im correct (which happens time to time) I dont believe that the 90's had vac or auto hubs, You have to get out to each front wheels and turn the center to the Lock arrow on the hubs themselves.

 

[FullSizeBronco1990]

naw, i dont have manually locking hubs, they are definitely electronic or vacuum powered.

 

[FullSizeBronco1990]

they are auto locking hubs that are supposed to engage when you put the truck into 4 lo or 4 hi, however they are not engaging.... because the driveshaft locks when i have it in 4 lo and it is neither electronic or vacuum, it sounds like a transfer case problem. is this a common problem for broncos?

 

[Redwagon]

they are auto locking hubs that are supposed to engage when you put the truck into 4 lo or 4 hi, however they are not engaging.... because the driveshaft locks when i have it in 4 lo and it is neither electronic or vacuum, it sounds like a transfer case problem. is this a common problem for broncos?

they lock with forward or reverse motion of the bronco, if they havent been used in awhile they maybe stuck, I HIGHLY doubt its related to the transfer case.

 

[catsnw]

Does the front dshatf turn when in 4hi/lo? If so its not the tcase.

 

[FullSizeBronco1990]

yea, that makes sense. So it is a transfer case problem..... fantastic.

 

[Ranger429]

The d'shaft locking is proof that both hub locks ARE engaging. Think about it... The tires are on the ground, and the truck isn't moving when you're crawling under it to grab the d'shaft. So if the tires aren't turning, and the d'shaft ISN'T, then they must be connected, via the hub locks.

If the d'shaft spins while the tires don't, then at least one of the hubs isn't locked.

:scratchhe


Feel free to correct me if I'm wrong Steve but if the rear tires are on the ground, the T-case is locked in to 4lo or 4hi it does not matter wether the hubs are locked or not. The front driveshaft isn't going to turn because the rear tires are on the ground.

i threw her in neutral and 4 lo and manually twisted the drive shaft. the drive shaft locked both times

How far did the driveshaft turn, not much I am guessing. 1/4" to 1/2" each way?

 

[raleigh]

:scratchhe


Feel free to correct me if I'm wrong Steve but if the rear tires are on the ground, the T-case is locked in to 4lo or 4hi it does not matter wether the hubs are locked or not. The front driveshaft isn't going to turn because the rear tires are on the ground.




How far did the driveshaft turn, not much I am guessing. 1/4" to 1/2" each way?

This^^^


Pull the hubs off and clean them, not hard to do and you can inspect them at the same time for any broken pieces.

 

[Gacknar]

Do this

How to test Ford Auto locking hubs on all TTB aplications.

1. Place transfercase in 2HI or Neutral.

2. Lying under vehicle, turn front drive shaft (one direction only).

3. Automatic hubs should lock after 1 to 5 turns of drive-shaft (one direction only).

After step 3 the hubs should lock, you'll know they are locked because you will hear a click from both hubs and you will no longer be able to turn the front drive shaft (in the same direction). If this is not the case then continue to step 4. If you can no longer turn the drive shaft (in the same direction) then skip to step 7.

4. If you can still turn the drive shaft (one direction only) then one or more of your Auto hubs is not working.

5. Continuing to turn the Drive shaft (one direction only).

6. Look at the u-joints for the front stub axles, if both are turning then both front hubs are malfunctioning, if only one is turning then the one that is not turning is locked and the one turning is malfunctioning.

Replace as necessary (preferably with manual hubs, Auto hubs have Yams in them)

7. To unlock the hubs, turn drive shaft in opposite direction until you hear a click from the hubs.

To check for transfercase engagement.

1. Place push button transfercase in either 4 HI or 4LO.

2. lie under vehicle.

3. You should not be able to turn front drive-shaft in either direction.

4. If you can turn the front drive shaft then your transfer case is not shifting properly.

 

[FullSizeBronco1990]

Gacnar, those are the steps that i used to see if everything was working properly and it showed that it engaged with the exception of the clicking sound of the hubs engaging. sure enough they did not engage. im gonna take them apart tomorrow. hopfully i will find what it the problem.

ranger, the d shaft turned half a rotation or so before acknowledging engagement and locking up..... im thinking the manual spring that usually pops out to lock the hubs is seized up from not being used in a long time.

 

[FirstPriority]

FullSize post your findings as I'm getting ready to test mine soon to see if they're working as well. I am interested in knowing what you figure out.

 

[Kingfish999]

convert to some manuals. 130$ or so and you wont have to worry bout this and they wont fail when you need them worst. plus it alows for 2LOW if needed. as sais autos have yams in them and have a very high tendancy to fail especially if not used. first thing i did when i got my 96 was convery to manuals cause the autos didnt work at all