47RE No 1-2 up shift fixed

[IBMobile]

Driving the other day and the transmission would not shift out of 2ed, came to a stop then accelerated and no 1-2 shift.   I stopped again and on acceleration 1-2 shift, very delayed 2-3 shift up and normal 3-4 shift.  After next stop no 1-2 up shift and it stayed that way.

 

Checked for codes and there were none.  Checked shift cable and it had free movement,  transmission fluid full but a little dirty (about 25-30k miles on it, pulling 5th wheel most of the time).   I pulled the transmission relay and drove around the block in limp home mode and it drove fine.  Three codes were set from pulling the relay out but that was to be expected but still no codes for governor solenoid or the transducer.   

 

With no 1-2 up shift and no codes the PCM might not be getting a signal from the transmission output speed sensor to know that the truck is moving.  So before I put the pressure gauges on I replaced the speed sensor.  The sensor cost $17 and removed and installed in less than 5 minutes with a 1" deep socket (have a pan to catch the fluid that comes out).  Road tested and all shift points are back to normal. 

 

I have since  serviced the transmission adjusted the bands.  A little fine metal on the magnet and nothing else. 

 

One other thing I've noticed is when the truck has sat over night it will take 5-8 seconds for engagement when shifted into drive.   I'm thinking torque convertor drain back.  The Transmission mechanic say that's normal for a 47RE but I don't remember it taking that long before.    What say you?  How long does yours take to engage after sitting over night or longer?

 

 

[Guest 04Mach1]

On my 97 if driven daily there is no delay when shifted into drive or reverse. If it sits for 2 or 3 days the delay is significant almost like it's slow to build pressure. 

 

On my 01 it takes weeks of not being driven to have a delay. 

 

I've seen quite a few 47RE and 48RE transmissions exhibit the delayed engagement, I don't know if it's normal but my 97 has done it for the past 100k+ miles so I'm not going to tear into the transmission until the it fails to engage and the truck doesn't move.

[015point9]

Time to engage when parked level overnight...2 seconds.

 

 

[01cummins4ever]

2 hours ago, IBMobile said:

 

 

One other thing I've noticed is when the truck has sat over night it will take 5-8 seconds for engagement when shifted into drive.   I'm thinking torque convertor drain back

 

 

5 to 8 seconds seems like too long, mine is about 1 to 2 seconds and that’s just sometimes,  If it’s taking that long to engage I think I would let it cycle in nuetral for a minute before taking off just to get things circulating,  

[IBMobile]

The transmission mechanic said the convertor will fill only when the trans is in gear, not park or neutral.  

[015point9]

1 hour ago, IBMobile said:

The transmission mechanic said the convertor will fill only when the trans is in gear, not park or neutral.  

I miss understood my mechanic then.

 

Not in park, but neutral will. What I was told.  

 

 

[JAG1]

I read neutral also.

 

           I noticed mine also taking awhile to engage in reverse. It happened when I got up to around 90,000 miles. It is the truck I use to haul the rv and sits more than the work truck. It took such noticeably longer that I thought the trans might be in trouble. So every week I drive the truck some to recirculate trans fluid, always putting it in neutral for a few seconds first. I think it helps to do that.

 

           I haven't tried going into drive after a long time parked, but reverse used to take awhile.

 

          Might be possible that neutral brings up the fluid to a point that its ready to flow into the convertor when it is placed in gear. Jon will have to tell us for certain tho.

 

          IBMobile that is a good story on your trans fix. I appreciate that tip/fix you found.

Edited August 25, 2018 by JAG1

[notlimah]

Pretty similar issue will happen if you tighten up the rear band a little too much...

 

 

don't ask how I know