trans slipping w/no OD flashing

[braddaddy]

Hi everyone. I have an issue with my transmission. I have an 02 expy xlt 4.8 with trans code U....I think that is the 4r70w?? 198K miles.
When I drive I have to fineese the trotlte in order to get the trans to shift to the next gear. It revs like its in neutral and sometimes when I let off the pedal it will shift as the rpms drop... sometimes this works and sometimes it takes some time. I am able to get it up to 50+ MPH. Reverse is fine, down shifting is fine. It does this going from 1st to 2nd and from 2nd to 3rd....then as im crusing in 4th it will surge higher? every 4 or 5 seconds.
I cannot get codes because the battery died as I let it sit for 3 months (bought a 2nd car...needed a 2nd car anyway). Got it jumped, took it to Autozone and they said not enough miles for computer to analyze and display codes because dead battery cleared the codes.
I have replaced the trans filter and fluid. Drove it for 5-6 miles and checked fluid level = ok. Ive been putting 15 miles on it daily for a few days now. But Im afraid to keep going to get enough miles on it to display codes for fear of making the problem worse.

Anyone have ideas? Ive searched the forums and google but I cant find my same symptoms.

Thanks in advance

 

[stamp11127]

The trans is a hydraulic unit that works on pressure to control the shifting. You may have a combination of low pressure and worn components.
In laymen terms - rebuild time.

 

[braddaddy]

Thanks stamp11127 for replying.....
I know there are electrical inputs that help the trans do its thing as well....
I'd like to start with easier possible fixes before I just go right to 'rebuild' though.

 

[stamp11127]

All the solenoid does is direct fluid flow from one hydraulic circuit to another....

Drop the trans pan and see how much grey gunk is there. If there is a bunch the clutches and bands are pretty worn.

 

[braddaddy]

I dropped the pan. There was a coating of grey gunk around the magnet and the pan. Like it was dipped in thin grey paint. Is that considered a bunch?
I replaced the filter and cleaned the mag and pan with brake cleaner.

 

[thenaaks]

I would say a thin layer of gunk on the magnet is completely normal. That's been my experience on dozens of vehicles I've serviced.

Sent from my SM-G900V using Tapatalk

 

[braddaddy]

Yeah.... There was a coating on the magnet as well as the pan.
I'm thinking / hoping it's electrical.... There was no warning... It drove fine and all of a sudden it began to slip. Reverse is fine- no problem going into reverse. It will eventually shift into all the gears, but it seems to me that it doesn't know "when" to shift.
And I get no code flashing on the O/D gear select.

I haven't had her scanned yet. I have only put 30 miles on her since the dead battery cleared the codes. I'm going to get her to 50 miles then I'll try having her scanned again.

 

[braddaddy]

My ABS light is on as well.... and it is braking weird... not as it normally would.
I didn't think this was related...but in reading up on the electronics of the trans, I see that rear ABS sensor is another input signal related to the trans and PCM. ???

 

[Bowesmobile]

Does it feel like the trans is slipping or just not shifting right. If its not shifting right, then its possibly electrical. But if it feels like its slipping, I would rebuild it or have it rebuilt. But you need to be sure of what its doing.

 

[txexpedition15]

2004 5.4

Hi everyone. I have an issue with my transmission. I have an 02 expy xlt 4.8 with trans code U....I think that is the 4r70w?? 198K miles.
When I drive I have to fineese the trotlte in order to get the trans to shift to the next gear. It revs like its in neutral and sometimes when I let off the pedal it will shift as the rpms drop... sometimes this works and sometimes it takes some time. I am able to get it up to 50+ MPH. Reverse is fine, down shifting is fine. It does this going from 1st to 2nd and from 2nd to 3rd....then as im crusing in 4th it will surge higher? every 4 or 5 seconds.
I cannot get codes because the battery died as I let it sit for 3 months (bought a 2nd car...needed a 2nd car anyway). Got it jumped, took it to Autozone and they said not enough miles for computer to analyze and display codes because dead battery cleared the codes.
I have replaced the trans filter and fluid. Drove it for 5-6 miles and checked fluid level = ok. Ive been putting 15 miles on it daily for a few days now. But Im afraid to keep going to get enough miles on it to display codes for fear of making the problem worse.

Anyone have ideas? Ive searched the forums and google but I cant find my same symptoms.

Thanks in advance

IT seems like i have the same problem so i will keep checking to see what anyone that helps thank you