hi all
another newbee question, the "rear antilock" light is lit all the time on my 1991 f 250. Any ideas what causes this?

Thanks!

Peter
Finland

 

I had the same problem and found that there is 2 wires that run to the rear diff. One of them had been severed. Attached it again and problem solved. Its pretty common.

 

Ok, I´ll check that tomorrow.
Thanks for the tip!

Peter

 

Check if you have an ABS sensor in your rear differential. They started using ABS sensors in the rear differential on some of the truck in 1990 and all the trucks used them by 92' (Little hall effect sensor with two wires going into it located on top of the differential housing) If your truck has one you probably need to change it. They are not very expensive. ($20-$30).

If you don't have a sensor in the rear differential then is your speedo working properly?. If not, change the VSS sensor in the tail housing of the transfer case. This one is a little more expensive ($100)

ABS systems "usually" fail safe and won't engage if they stop working. So if the ABS system does not work your brakes should work the way they did in the olden days before they invented ABS systems.



Seb...

 

well I removed the sensor on top of the differetial and cleand it - problem solved!! Thanks!!!

I need to get a new sensor since it looked quite worn. Cant find one on the internet, is this a ford part only, if so, anyone know the partnumber?

Thanks!
Peter

 

[QUOTE=petersandberg77]well I removed the sensor on top of the differetial and cleand it - problem solved!! Thanks!!!


The last one I bought from Ford for about $30. So I did not bother trying to get one aftermarket.

Cleaning definetely helps. If you had a lot of iron filings built up on the sensor you probably should also consider changing you differential oil. If I remember correctly from my manual the differential oil should be changed every 160k or so.


Seb.....

Seb.

 

The pickup on the old VSS was square metal, now they cover it with a plastic so as to deferr the iron filings from sticking and disrupting the sensor from passing info.

 

yes I will replace it, but the dealerships where I live aint that well equipped with parts to imported cars....so it would help if i had the part number for it.

any suggestions on what kind of oil i should use for the diff. and how much?

and another question, is the sensor on the differential connected to the trnsmission in some way? (speedometer, vss) i read somewhere on the forum that it might.

since i am having problems with my transmission (e4od). It wont shift properly until after about 10 to 15 min after starting up (cold) and the tach is also dead for the same time. then it runs flawless until i turn the motor off, then the same thing again when starting her up again. but when motor warm it only take about a minute for the tach to "come alive" and the transmission to shift properly.

Thanks Seb!

Peter

 

...orgot to mention that i changed the sensor for the tach to a new one and it didn´t help...

 

Put up a signature of truck info please...... year and models are different in some respects.

Several Ford dealers do send overseas.....

www.Fordpartsonline.com and Kerny Mesa Ford........ http://billm.web.aplus.net/

 

sorry, here goes:

f 250 xlt lariat
1991
7.3l


thanks for the links!

peter

 

Peter,

My appologies I just realized that you are from Finland after you called your truck an "import".

If your speedometer is not working right you will have problems in the shifting of your E4OD transmission. You will need to replace the VSS (Vehicle Speed Sensor) which for your truck (90) is located in the tail end of the transfer case. It is a mechancial sensor that is gear driven with an electrical sensor that piggy-backs onto it. This unit is a little more expensive ($CDN 100) and should be available aftermarket as is was the standard from about 87' to 91'. The way it works it the mechanical drive drives you odometer while the electrical signal drives you speedometer and is used by the E4OD controller.

Note, Ford started using the same speed sensor (in the rear differential) in 1992 to supply the signal for the ABS, speedometer, and odometer when they switched to the all electronic dash. Some people still call it the ABS sensor on the newer truck while in reality it's more important function is providing the vehicle speed for the E4OD control.

What you need to do is replace your VSS to get your E4OD to shift properly again. You will need to transfer the plastic gear on the tip of the old VSS to the new VSS before you install it. The odometer cable just pulls out of the socket at the back of the VSS. Give it some penetrating oil and a good pull; they sometimes get a little rusty. Don't try and pull the Stainless still clip in the VSS housing, it is not meant to be removed and acts as a spring only, all you need to do is pull the odometer cable out. There should be a new clip with the new VSS and all you do is push the odometer cable.

The oil in the differential is 75-90W oil; however you will have to add the "limited slip" additive otherwise you could damage your limited slip differential. Best to check with a transmission shop, I have not done this recently.


Hope this helps.


Seb....

 

Keep this in mind. You can have differential problems cause the ABS light. If you loose a side bearing you will get to much air gap on the sensor. It will set a fault.

I not saying you have a problem just keep it in mind down the road. I have found two 10.25 rear ends that had lost bearing when people brought the truck over to me to look at an ABS problem. It is a good thing they were interested in the ABS problem because if they let it go it could have been nasty.

 

Very good point Catfish, there should not be any wear on the ABS sensor as there is a small air gap under normal operation. With a worn cage bearing the ring gear could touch the sensor and damage it.

Probalby a good idea to drop the cover, change the oil and do an inspection of the rear end while you are at it.


Seb....

 

Seb...
my speedo and odometer works just fine, just the tach that is dead for a few minutes and the tranny not shifting(after start)....what is strange is that the tranny works perfectly when the tach finally "comes to life" (lack of a better word) until the next time i turn the engine off, then the same procedure when starting her up?

could it still be the VSS?

I will do a overhaul on the rear end, don´t think it been don lately....

Thanks for all the help guys, really appreciate it!!

Peter