98 1500 with a demon

[natthan89]

Ok guys I need some help really bad. I have a 98 dodge ram 1500 4x4 360 truck. It will manually shift thru the gears fine 1st thrugh od. it's a automatic transmission but if I pull it to drive it will go to second like it's in limp mode but it has no cel. I have replaced the pcm governor pressure sensor and solenoid tps iac output speed sensor diff speed sensor checked all wiring 3 times done a multimeter test on it all wires all good. Fluid and filter change. Pulled the valve body replaced one of the screens in it. Still the same thing. If anyone could shine some light this way I would be so thankful. And the pcm I replaced it with was used .

 

[rowdyram]

A second gear start when in drive means governer pressure is higher than throttle pressure.
Potential causes
Bad oss
Bad gov solenoid
Bad gov pressure sensor
Misadjusted TV cable
PCM
The speed sensor and gov sensor or solenoid are all very common.
The best way to diag this is to monitor gov pressure in gear at a stop should be 0 psi and as oss speed increases the gov pressure should increase accordingly until it becomes higher than TV pressure which then shifts to 2nd.
I know you replaced the solenoid and sensor but "new" and "works" are not the same.

 

[natthan89]

Yes new isn't the same as working. But I've replaced 1st with some off eBay it worked for about 30 minutes then it stopped shifting again so I went to dodge and bought oem sensor and solenoid and it worked through one shift pattern the pressure of the solenoid jumps all over the place while looking at the vitals with a Chrysler drb scan tool what should I do? And thank you for your reply

 

[rowdyram]

What is your oss reading while stopped?

 

[natthan89]

I'll have to get back to you on that when I get the drb again I can tell you that the speedometer only works sometimes could that be my issue? I bought the OSS from advance and I've had issues with aftermarket parts before

 

[rowdyram]

The oss is in the o/d unit in the trans not the one in the t case that's the vss. The vss is for the speedo

 

[natthan89]

I've replaced the oss the vss the governer pressure solenoid and sensor still same thing and no check engine light this thing is driving me nuts

 

[jbmobbs]

I've replaced the oss the vss the governer pressure solenoid and sensor still same thing and no check engine light this thing is driving me nuts

Do what I did, put an nv4500 5 speed in it lol

 

[rowdyram]

Have you checked your trans relay? Swap it out with an unimportant one (horn)

 

[ADudeOnSkis]

Do what I did, put an nv4500 5 speed in it lol

 

[natthan89]

I've thought about the manual transmission and I have also bought a new transmission control relay

 

[rowdyram]

 

[natthan89]

4.83 to pin 2 could it possibly a valve in the valve body barely stuck open making it do what it's doing

 

[rowdyram]

A second gear start means gov pressure is higher than throttle pressure @ idle. Because it works in manual low that proves the intermediate band will release ruling out a valve issue.

 

[rowdyram]

When you get access to a drb again look at your oss gov. solenoid DC % temp and pressure. I've seen a hand full of pcms command gov opening @ idle...

 

[natthan89]

I don't remember what the temp was but the pressure was all over the place. I flashed the pcm for the tsb 210400 tsb and it didn't change anything I have a different computer I'm going to put in and flash and see what happens if it doesn't work what else could it be. And I really appreciate your help and advice it been helpful. Oh on another subject my speedometer doesn't work even with a new vss.

 

[rowdyram]

If the pressure is erratic and you've covered all these bases I see no option but more defective solenoid or sensor. I could be missing something but your symptom screams solenoid or sensor.
And the fact that they worked for a while after replacing. Possible short in the VB harness burning up new parts? Ohm them out according to the pin out.

As for the vss... It has to be rotated to engage the gear. Did you verify its touching the drive gear?
How I usually diag those is pop them out pull the gear off and put the shaft in a drill and spin it have someone watch the speedo.

 

[natthan89]

My speedometer is electronic

 

[rowdyram]

My speedometer is electronic

I know. Should be a gear driven sensor in the t-case. That is the one I'm talking about

 

[rowdyram]

This is a image for fwd but same sensor