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, 20196 yr by IBMobile

I guess I'm not following you. I don't typically shut my engine off between reverse and drive.

 

A converter will drain back when it sits for extended periods with the engine not running; ie. overnight.

On 4/19/2019 at 7:30 AM, IBMobile said:

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.  

I was surprised when mine did this too. After sitting for weeks at a time. It did this only a few times and has gone away. I kind of expect it a wee bit from time to time and usually let it roll backward in neutral for a bit to get things circulating after sitting. I know so little about transmissions though.

 

I hope Dan it's minor and since you haul a fifth wheel its just a simple matter of a sensor or symptoms of more frequent trans services required.

Edited April 20, 20196 yr by JAG1

When I was talking to the trans rebuilder about the governor solenoid and the problems with the transmission he mentioned that he has come across a few transmission filters causing problems.   The drain back problem started after I serviced the trans and a 1,000 mi trip towing the 5er.  I thought maybe the problem was induced during the service and it took that long for the problem to show itself.

This weekend I pulled the pan and did an inspection.   I checked the bands, installed a new filter and fluid; then road tested every day this week with no problems.  So what was wrong? I have no idea but I'll be leaving this weekend on a 2,000 mi 3 week trip towing the 5er.  I'll know if there is a problem by the end of this trip.

Well, after towing the 5er for 788 mi the problem has reared it's head once more.  Pulled into Mt Shasta, CA and after unhooking the 5er went into town where, this time, at times the transmission would not shift out of 1st and other times no 2-3 shift.  It would never shift into 3ed.

 

This morning, after an extensive road test, I found that if the truck is put in park, turned off, restarted, and put in drive the transmission will up shift normally but once stopped for say a red light, and accelerate again there is no 1-2 shift.  When this happens I can shift the transmission from drive to neutral, while going 10-15 mph, then back to drive and the upshifting becomes normal. 

 

This afternoon we went for a drive and about the first 10 mi it was having problems.  The next 40 plus miles the transmission shifted fine.   Tomorrow we'll be heading to the Portland area and see how it goes..           

Drove another 380 mi and no problems, trans shifted fine.   What the heck.

Dont you love gremlins.

Have you cleaned all battery terminals. 

 

Unhook your batter's and see  if ones dead. 

 

Could be electrical connections causing you trouble

All battery terminals are clean and tight.

 

I haven't checked the battery but will do tomorrow before we leave for Crater Lake National Park.

 

All connections look good and mods have been done but one never knows.

Well I've towed the 5er over 2000 mile with this off and on problem.  It's mostly on again now.  Tomorrow I start the last leg of this trip with a 400 mile pull from Bridgeport, CA to San Marcos.  When I get there I'll have all the tools to tear into this problem.   

I finally have had time to work on this problem.  

 

First thing was to flush the transmission due to the trans temp going over 250°F and the fluid was dark in color.  This was accomplished by disconnecting the transmission cooler return line at the left rear side of the transmission and sliding a length of 5/8" heater hose over the pipe and the other end into a 12qt oil drain.  I then added 7qt of ATF through the transmission with the engine running and in neutral.

 

 

The pan was then removed and the housing for the transducer and governor solenoid was replaced.  The new transducer and a Borg Warner governor were installed in a modified housing.  I removed a housing from a junkyard 46re and modified it to allow fluid to enter the governor solenoid freely for 360°.   The 3-4 accumulator spring was replaced with a thicker spring due to their high failure rate.  

 

  Borg Warner solenoid is on the right

 

  modified housing on the right

 

I added a drain to the pan.  Went to NAPA and got a M12 x 1.25 x 30mm drain plug, nut. and plastic washer.  Using a strong rare earth magnet on the outside of the pan to hold the nut in place, an area was found where the drain plug would cleare the valve body and a large surface area for flat contact with the sealing washer.  The hole was drilled 1/2" and the nut tack welded to the pan in three spots, this was done so not to warp the pan and to allow fluid to be able to drain under the nut. 

 

  left front corner

 

 

Initial road tests, post repair, the transmission has a smother, softer shift quality. The end of July I'll be towing the 5er on a 1,000 mi trip so that will be a better road test. 

Why did you replace the governor solenoid housing?

 

EDIT: Never mind, I reread your post. For what it's worth, that modification is completely unnecessary and actually does nothing. As a matter of fact, most of the GM conversion housings that are on the market actually orifice the feed to the solenoid. The governor circuit is a dead end circuit, so there's no flow, making the need for more volume to the solenoid nonexistent. I typically introduce a small calibrated leak into the governor circuit to allow a small amount of flow through the system which smooths operation and quickens the circuit's response to commands from the solenoid.

Edited June 15, 20195 yr by Dynamic