Rpm gauge went out, and the tranny started slippin...

[JDaulton]

I just changed the tach sensor, by the way its $80 at the stealership! and still no dice! It works every now and again, and I've been drivin on it for a week. But i'm afraid I am going to break somethin if i keep this up! Any information would be greatly appreciated. Thanks again

 

[HankHill]

do you think maybe its defective? I have heard that if the tach sensor is broken you will recieve erratic shifting from the e4od auto trans but if you have a c6 it shouldnt have effect on that because it is vaccum but from reading the 94CCF-350 from under your name I'm guessing you have the e4od, another thing you might want to try checking for your shifting problems could be the FIPL its right on the IP you can take a paperclip and carefully slide it into the middle wire on that pigtail, then turn the key on and with a volt meter check the voltage from idle to wot, I'm not positive but its like 1.1idle and 4.0 vdc mine is currently 1.09v and 3.80vdc at wot

 

[JDaulton]

I'm not sure if it is defective or not. When the gauge suddenly works again, the truck performs exactly as should. I just cant figure out what is causing this intermittent problem. As of right now, the truck wants to take off in overdrive if left in drive. And slips the whole way. Now if i shift it manually it works but still slips in 4th. So somewhere somehow the relation between the tach and the faulty shifting are related. I just feel as though as if i find out why the tach is not working, then the tranny problem will be solved. And I will test the wire, but what does wot stand for, and what information will i gain by reading this, Thank you very much for the support.

 

[JDaulton]

And yes you are correct it is an E4od

 

[david85]

I can tell you for sure that you won't get a new transmission for $80. Yes, its a rip off but you are better off replacing that sensor and be done with it.

You can try removing the sensor, cleaning it and checking the wires very closely for frayed insulation or broken copper strands showing through. Sometimes you can get them to work again for a little while.

 

[jimmys f250]

mine was doing that,,,was hitting the sides of the case,,,I just hit mine the tach ,,a lil knock with my nuckles and it has worked since,,,but that was on mine,,try it

 

[JDaulton]

Thanks for the input guys. I have the new sensor in already but i still have no rpm gauge, any ideas where else the problem could be? maybe in the E4oD? or may the banks trans command?

 

[grog85]

wot stands for Wide Open Throttle.

 

[david85]

Sorry, I misread your original post. My bad.

Sometimes the contacts on the back of the cluster can get dirty and prevent signals from getting through. I've heard some other guys are able to solve some of these strange problems simply by removing the cluster assemble and reinstalling it.

I don't *think* the trans command can cause this.....

If the PCM is having internal issues or power supply issues, you generally will lose all but 4th gear in forward and have no speedometer/tachometer read out.

 

[JDaulton]

Alright, i have tried everything i can think of... I just dont know what else to do... Has anyone ever changed the pcm on an e4od? Could this be related? I hope thanks for all the input hank! Much appreciated

 

[JDaulton]

i apologize, David*

 

[Agnem]

I don't have the schematic in front of me, but it seems to me your looking at a bad wire. If the tach reads correctly one moment, then not at all the next, that sounds like you have an intermittent short or open connectivity. IIRC the tach circuit branches off to the trans PCM. Your problem is between that point and the sensor. Find that junction, and check the wiring from there. A bad ground could do this to you as well.

 

[international]

I think the reason my trans fried was because of it not being grounded very well.

 

[JDaulton]

I made a new ground, from the battery to the frame, and from the frame to the tranny. Still nothin. The motor is grounded, and the connections are good. I have also checked the tach sensor wires. And I've traced them all the way back to the pcm. They are good, And tested out at 0 resistance on the ohm meter... Any more ideas? thank you very much!

 

[trackspeeder]

Thanks for the input guys. I have the new sensor in already but i still have no rpm gauge, any ideas where else the problem could be? maybe in the E4oD? or may the banks trans command?

Remove the trans command, see what happens with the tranny.

There is a wiring issue or problems with the PCM. Check the PCM for water leakage. Sometimes they can get water damaged from leaks.