[fordfool]

98 3.0 vulcan AX4N

I replaced the forward control valve and the 3-4 shift solenoid. The pump looked good and Ive done 2 flushes and added seafoam twice. What am I missing? I think it may be shifting into O/D because when im at highway speeds and let off of the throttle and pull the shifter down from O/D to D, it seems to downshift possibly. At 70 it should be going fast enough not to make a difference if I was only in 3rd gear already and didnt have O/D. Could it go into O/D and just not stay there, not lock in or something? Could that be a lock-up issue? I can feel the TC lock-up while its shifting thru the gears.

 

[shoz123]

What's your rpms when at 60 mph? Same in 3rd and 4th?

 

[fordfool]

@60 MPH with the shifter in O/D or D, the RPMs are 3K. If the shifter is in O/D and I let off of the throttle and im coasting @ 60 my RPMs are 2k. When I let off of the throttle the RPMs drop quickly to 2k, but then its a steady 2k like its engaged.

 

[shoz123]

That sounds like it shifts to OD when you let up on the throttle?

If so it may be the TPS sensor. You can check this with the key on engine off and backprobing the TPS sensor. It should read just under 1V when the throttle is closed, definitely not over 1V. And smoothly progress up to about 4.5V at WOT. Any skipping or hanging up of the voltage means it is no good.

 

[fordfool]

I checked the TPS and it did act funny around 2Volts, so I replaced it. Still no O/D.

 

[outatyme357]

Don't mean to hijack the thread but what would it mean if my TPS is reading 4.16v throttle cosed - 0.46 WOT? car seems to run fair. Does this mean my TPS needs replacement?

 

[mwt]

Set the cruise @ 65 and tell us what the rpm's are.

Mike
:dunno:

 

[millermagic]

Overdrive on these cars is the 4th gear that works in your car.

 

[shoz123]

QUOTE (outatyme @ Mar 12 2009, 09:39 PM) index.php?act=findpost&pid=708106

Don't mean to hijack the thread but what would it mean if my TPS is reading 4.16v throttle cosed - 0.46 WOT? car seems to run fair. Does this mean my TPS needs replacement?[/b]

The normal TPS voltage should read ~.85v-.99v at closed throttle and ~4.5V at WOT. There should be a smooth upward transition as you slowly open the throttle. Beware digital voltmeters that have auto ranging as there may be a perceived jump as you change decimal values on the read out, such as at <1v to > 1v.

You should also make sure the input voltage is close to 5V.

 

[fordfool]

QUOTE (mwt @ Mar 12 2009, 11:47 PM) index.php?act=findpost&pid=708108

Set the cruise @ 65 and tell us what the rpm's are.

Mike
:dunno:[/b]

@65 the RPMs are 3200 in D. When I change to O/D, they jump just a little maybe 3300.

 

[shoz123]

If there is no OD and it is being commanded then there should be a DTC.

 

[fordfool]

It's been getting a p0761 the entire time. The retaining clip wasnt broken, but I replaced it and the valve anyway.

 

[shoz123]

Here is the solenoid 3 troubleshooting.

 

[mwt]

3200 @ 65 means it is definately not shifting. Is the flashing light still coming on

Mike
:dunno:

 

[fordfool]

QUOTE (mwt @ Mar 15 2009, 07:18 PM) index.php?act=findpost&pid=708889

3200 @ 65 means it is definately not shifting. Is the flashing light still coming on

Mike
:dunno:[/b]

I dont have a flashing light. Just the check engine light. If im in O/D and moving at speed and let off of the throttle and coast, the RPMs drop to normal, maybe around 2k as long as I dont push the gas. If im coasting along and I pull the shifter down to D, the RPMs jump straght up. It seems like its in O/D but it wont stay there if any demand is put on it.

 

[fordfool]

How does the tranny know when to shift out of O/D?

 

[shoz123]

Speed sensor.

The shifting parameters are based on TPS reading and the vehicle speed.

 

[fordfool]

Is there anyway that the Speed Sensor could work fine except for when O/D is called for? Or up to a certain range? I have not had any problems with my speedometer.

 

[fordfool]

QUOTE (fordfool @ Mar 18 2009, 07:25 PM) index.php?act=findpost&pid=710130

Is there anyway that the Speed Sensor could work fine except for when O/D is called for? Or up to a certain range? I have not had any problems with my speedometer.[/b]

My speedometer runs off of the vehicle speed sensor, so maybe I should be looking at the turbine speed sensor or the transmission speed sensor whichever it's called.

 

[shoz123]

Maybe the problem is from the speed sensor to the PCM to the tranny then?