TC not locking in third

[101st ABN]

My truck has never had the converter lock in third gear. Is this a computer issue? Reflash?

 

[rscurtis]

With 3. 73 gears, it should lock at about 47 MPH. If you always drive with the OD enabled, it won't lock in third gear unless you're really laying into the power.

 

[JJPage]

Sometimes it's really hard to feel, especially with a stock trans. If you hookup a mystery switch(tc lock switch), you can manually lock it to test the solenoid.



Can you feel it lock up in OD? If so, it almost certainly is locking in 3rd, just difficult to tell.



On your 03 an updated flash to your ecm should not affect your trans operation, as it has a separate pcm(powertrain control module) that manages the trans.

 

[101st ABN]

It does lock in OD but not in 3rd. Yes your right difficult to tell when the trans was stock now have a built trans its more noticable. I have the edge with attitude too and it also indicates when lockup happens.

 

[JJPage]

Let's wait until our resident trans expert cerb checks in, I am not saying this lightly/sarcastically, he most likely has an idea or reason for what you believe is not taking place.

When my APPS was faulty it caused problems with my trans behavior, there is a procedure to reset the APPS, I do not know offhand what that is, but i do know how to re calibrate it manually(timbos), here is a link, click on calibration: Timbo APPS

 

[cerberusiam]

Like rscurtis said, it probably won't lock in drive unless you hard into the throttle. The lockup algorithms on the early trucks are just not as aggressive as the newer ones. However, with a decent TC you should be able to feel it lock under power. Try driving it hard with OD on and off and see if you can make it lock in drive.



If not you might want to ask if there is a flash that will change that behaviour.

 

[rscurtis]

When I first got my signature truck, I didn't (still don't) care for the high speed LU in the OD off mode. I inquired about having that changed, but was told that was not possible by the dealer. I would prefer the LU in the low 30's like my '95 did. The '03 certainly has the power.

 

[AEdelheit]

I picked up a ATS CO-Pilot of CL for $100 to control LU, works great!

 

[JJPage]

When I first got my signature truck, I didn't (still don't) care for the high speed LU in the OD off mode. I inquired about having that changed, but was told that was not possible by the dealer. I would prefer the LU in the low 30's like my '95 did.

I picked up a ATS CO-Pilot of CL for $100 to control LU, works great!

My TC locks up in 3rd, whether OD is on or off, I do not remember if it did that prior to DTT's work, they built my trans when it was almost new. DTT is using a separate 5 vdc source for the control.



I built two circuits for Trans/TC control, basically, I grounded pin 6 and 7 in parallel, on the trans control plug with 1/4amp 20 ohm resistors. The switch for 6 locks it in OD, 7 locks the TC.



You have to use a 20 ohm resistor(not 10 ohm) if you build the circuits in parallel, because the resistance becomes 10 ohms(half) in a parallel circuit, and it will be too close to the lower spectrum of the monitored range, and will throw codes. This is an easy upgrade, may have cost me $20.

 

[101st ABN]

I have a georend tc, drove it hard od off and it did not lock. I recently replaced the apps too (timbo). I will look in to programing the PCM.

 

[JJPage]

I have a georend tc, drove it hard od off and it did not lock. I recently replaced the apps too (timbo). I will look in to programing the PCM.

I tested mine again today, locks everytime. Also using my ground switch with OD on(overdrive locked out) I could lock and unlock my TC at will, about a 200 rpm difference in 3rd gear.



neglected to flip the switch off, locked shifts are really harsh, pushed on it in second gear with the TC locked, spun the 35's at 1500 rpms, not sure line pressure is sufficient to hold the clutches that low.



Call your trans builder (Goerend) ask them what's going on... .