well i rebuilt my transfer case and replaces some broken parts and was confident that it would work once reinstalled. before the truck would not go unless in 4 lo. now after i rebuilt t-case it will go but only 5 or 10 mph and the engine just revs and revs when you hit the gas but won't change gears or go over 5 or 10 mph. is this likely a problem with the tranny or could this be a result of me doing something wrong in the transfer case?it seems to me like if it was the transfer case it wouldn't go at all. before any of this happened everything was fine with the tranny.

 

Well, it seems to me your tranny is auto, isn't it???
What model???
Is your T-Case Electric or Manual Shift???

I have some ideas on your problem, but need more info...

 

yep my tranny is auto-E4OD and the transfer case is manual shift. i don't think it's the t-case linkage but i'm going to try and eliminate that possibility today by disconnecting it and putting it into 2 hi by moving the piece that the linkage connects to by hand. cause it sort of seems like it's in 4 lo but i don't know.

 

At T-case there is a "Low Range" switch, it is supposed to provide ground for the Low Range lamp at cluster BUT ALSO to indicate the ECM the T-Case is in low range and it has to recalculate shift points.

Be sure this switch and the indicator lamp performs, double check the VSS sensor also. I'm guessing the tranny works fine in 2WD and 4WD High range, isn't it???

 

The tranny worked fine before the case went out. but now the tranny does the same thing whether in 2hi, 4 hi, or 4 lo. the engine just revs and revs and the tranny never goes out of first. what is a vss sensor? i have a feeling some kind of sensor is causing this but where is this vss sensor? how do i test whether the 4 lo indicator is working? i think something is screwed up with that plug that goes into the t-case cause the cluster is not performing right. but would that really cause the tranny to not shift at all? aslo if i wanted to try and pull codes from the ECM or whatever it's called, can i use a digital voltmeter instead of one with a needle? THANKS

 

Well now I had more info...

1º If tranny do samething in 2H, 4H or 4L it meas problem is caused by VSS sensor. Depends on what year is your truck it can be installed at the T-case output shaft OR over the rear Axel. It also cause the Speedmeter don't show readings. Since ECM needs know vehicle speed to provide proper shifting if there is no Speed signal, then ECM "thinks" Truck is not moving so it keeps 1º gear engaged.

2º 4H and 4L switch works fine if the proper cluster lamps turns on.

3º Yes you can use a digital voltmeter BUT count blinks will be a bit difficult since digital Voltmeters have slow responce. I preffer use a LED diode series connected to a 1K resistor, so you can see the lend blinking pretty nice...

 

THANKS man. you definately know your stuff. I went to change a seal in the rear output shaft of the t-case and sure enough the yellow plastic gear that goes around the shaft that the speedo cable sticks into was not stuck down where it was supposed to be, unless it jarred loose when i jarred loose the shaft housing. i hope that was the problem. but is that the vss or is the vss an electrical thing. and if the speedo gear yellow plastic thing had slid loose why did it do that and how do i seat it so it stays put. there's nothing that stops is from sliding back. how hard is it really to use the digital voltmeter to read codes? is it inpractical? cause i've never done it before and i want to make it as easy as possible. the haynes manual directions make it seems like rocket science. what is a led diode series and what is a 1k connector? this part is something i'm gonna have trouble wth cause i don't know what this stuff is when it comes to the code pulling. on the other hand i have to do it cause i can't drive the truck to have it read. i bought a digital voltmeter but i can return it if you think it's way better to do it the other way. but is it more expensive for the led diode, resistor method? and can you tell me EXACTLY what to buy and give me a brief idea how it's done?cause the Haynes manual is confusing. THANK YOU so much, you are helping me save money that i don't have to spend anyways and possiblt helping me recoup money which i badly need so I REALLY REALLY appreciate your help. And you really know what you're talking about!

 

Well, I'm glad my ideas help you...

First at all, YES! that's the VSS sensor, it seems to me your truck year is between 1988 to 1992, isn't it??? those trucks still having VSS sensor located at T-Case or Tranny Output shaft.

This Sensor has to be fully seated to case and holding in place by a small "Y" clamp and 1/4" bolt, there is a plastic gear at the nose of this sensor and it should be moved by the output shaft while truck runs to provide proper signal to ECM.

Some trucks using old stile clusters with mechanical speedmeters, also use a cable attached to the end of VSS, for speddmeter operation. You have to be sure there are no missing teeth on plastic gear AND VSS sensor is fully seated against output shaft case and hold in place by clamp.

- Digital meters can be use, just don't move your eyes from the meter while you count blinks or you can easily loose some of them.

- LED Diode are those used on electronics to iluminated or as indicators, have a look at any electronic device, any Gren, Red or Yellow small lamp will be a LED diode, You can obtain it at any RadioShack store and also the 1K resistor BUT you 'll need a minimun of electricity knowledge to connect it. It is supossed to use instead of voltmeter, same connections... and it will blink. LED diode and resistor will cost less than US$ 1,oo