Transmission hangs in second

[IBMobile]

I drove the truck for the first time in 4 weeks and started getting a no 2-3 up shift condition.  It will up shift when backing off the accelerator.  All the other shift points are at the proper speed/throttle position.  

 

The transmission speed sensor was replaced 8/8/18 (107,893mi) due to no 1-2 up shift but would start off in 3ed if transmission relay was pulled.

Transmission was serviced with front and rear band adjustment 9/1/18 (108,024) then a 1,000mi trip in October pulling the 5er with no problems. 

 

The transmission now has 109,362mi.  I'm thinking it may be the governor pressure sensor and solenoid.  They were replaced about 45k mile ago.

Has anyone else seen a problem like this?  What say you @Dynamic? 

Edited April 13, 2019 by IBMobile

[JAG1]

Take it out and give it some more exercise dan..... don't be hard on it just get it up to full temps and report back.

Edited April 13, 2019 by JAG1

[Dynamic]

The first suspect in any problem with gear selection in the first 3 gears would be the transducer and/or possibly the governor pressure solenoid. If I had to throw parts at that problem, those would be the ones (replace them as a pair). To verify, though, I would put a pressure gauge in the governor pressure port and monitor what the governor pressure is doing.

[Mopar1973Man]

In my case did exactly that and 2k miles later the transmission failed. While you there take note of the debris in the pan it might be time for rebuild.

[IBMobile]

22 minutes ago, Mopar1973Man said:

In my case did exactly that and 2k miles later the transmission failed.

That's what happened the last time I replaced them.  When I serviced it 1000mi ago the fluid and pan were clean.

 

  Right now I have the left battery box out while doing a new type of grid heater bypass modification.  I'll get my pressure gauges on it maybe later today.  

[IBMobile]

I installed the 0-130psi pressure gauge and have taken the truck out on two road tests.   The transmission is shifting fine at this time.   I'm going to keep the gauge on for a few days and drive the truck some more.

 

The pressure readings were taken with my helper, my wife, driving and calling out the road speed. 

MPH       PSI    shift

  0             0

20           20      1-2

33           40      2-3

45           50      3-4

56           74      convertor locked

65           80      convertor locked

[Evan]

Pressure seems to be below stock. 

I dont like seeing that . I think idle should be 50-60 then climb to 90-100 wot.

 

20psi to me doesnt sound good.

 

What is psi converter locked with your foot on the floor?

 

I'd make sure the TV cable doesnt have any slack in it. Then I'd make sure at wot tv arm doesnt have travel left. If you can move TV arm more by hand at wot I'd tighten cable  till it pulls the arm as far as it can possibly travel. This will ensure your building pressure as pressure rises as you push the throttle down further.

 

I think spec is wot shifts at 2700-2800 less pressure will shift sooner more later

[Mopar1973Man]

Remember TV cable adjustments will change shift points and pressure. If the TV cable is not adjusted properly then the shift pattern can be altered. 

[IBMobile]

9 hours ago, Evan said:

. I think idle should be 50-60 then climb to 90-100 wot.

Thanks for the info above.  I believe those pressures are for the line pressure test at the accumulator test port.  I am checking the governor pressure at the governor test port.  

 

The governor pressure at idle should be 0-3psi  and climb 1psi/mph to 30mph.   If governor pressure is above 3psi at idle then there is a fault in the governor valve system.  If the governor pressure is to low on the road test then there is ether a bad governor pressure solenoid,  pressure sensor (transducer), or control module.  Since the test pressures fall within parameters I'm going to do more road testing. 

 

I hope it was an anomaly and the transmission just needed to be 'exercised' like @JAG1 suggested.

 

 

[JAG1]

I am hopeful is all. How much metal in the pan? I just pulled the magnetic plug and drained mine as it's not time for a full trans service yet but want to change out the slightly burnt. I went to 8,000 ft elevation in only about 5 miles hauling 3400 lbs and temps got up to 180 or so. You could see the slight discoloration. The magnet had some metal.... enough to cover the tip of my thumb and forefinger.

 

Staying  hopeful ........ I have often wondered how good to stick a few rare earth magnets to the bottom of a factory pand..... if that is any benefit to help keep the filter. Those magnets are very strong.

Edited April 14, 2019 by JAG1

[IBMobile]

The fluid is clean and full with 1,000 miles on it.  I don't have a plug on the pan and don't want to pull the pan off for inspection just yet.

[Mopar1973Man]

The last thing I've seen where transmission pressure was low, the filter was filled with debris. 

[Dynamic]

On 4/13/2019 at 10:02 PM, Evan said:

Pressure seems to be below stock. 

I dont like seeing that . I think idle should be 50-60 then climb to 90-100 wot.

 

20psi to me doesnt sound good.

 

What is psi converter locked with your foot on the floor?

 

I'd make sure the TV cable doesnt have any slack in it. Then I'd make sure at wot tv arm doesnt have travel left. If you can move TV arm more by hand at wot I'd tighten cable  till it pulls the arm as far as it can possibly travel. This will ensure your building pressure as pressure rises as you push the throttle down further.

 

I think spec is wot shifts at 2700-2800 less pressure will shift sooner more later

Those are governor pressure readings. They look completely normal.

[IBMobile]

Transmission acted up yesterday afternoon for a short time. After road testing for 4 miles it happened 3 times in a row then no more.  Road tested again last night with out a reoccurrence.  It would only not 2-3 up shift during full throttle acceleration.  If throttle is backed off then up shift happens. 

 

Governor pressures when problem occurred: 

MPH         PSI       RPM  

  0             2-4        800

 45            56        2800/2ed gear    

When shifting is normal:

  0              0          800

 45            92        3400  2-3 shift at full throttle 

Edited April 17, 2019 by IBMobile

[Dynamic]

What kind (brand) of governor solenoid is in there right now?

[IBMobile]

1 hour ago, Dynamic said:

What kind (brand) of governor solenoid is in there right now?

I don't know.  It was replaced 11/09 with 63,500 mi (46,000 miles ago) when the trans was rebuilt. I'll try to find out.

Edited April 18, 2019 by IBMobile

[IBMobile]

On 4/18/2019 at 7:19 AM, Dynamic said:

What kind (brand) of governor solenoid is in there right now?

After 9 1/2 years he couldn't recall.  

 

One other problem that has been going on for about 6 months is the torque convertor draining over night and takes about 2 seconds for reverse to engage then up to 5 seconds for 1st to engage after backing up; it's ok the rest of the day.  

[Dynamic]

Converter drainback is normal, but the time it takes to refill can be minimized within the valve body. A good valve body will fill a completely "drained back" converter before you even get your seat belt on. But 5 seconds to engage forward AFTER you have already backed up (converter functional at that point) gives me a little pause, though.

[Evan]

Can the converter even drain in reverse or time it takes to move stick to drive 

[Dynamic]

The converter drains back when it sits with the engine not running.