2003 auto 4R100 I guess, with 205,000 miles, DP tuner.
came up to my huntcamp yesterday towing about 6000lbs. drove normall almost the entire way up until it didn't want to shift outta first gear climbing a small hill, had to pedal ( back off quickly ) for it to shift. trans temp was 180 at time. after that hill it climbed to 200 and came back down a little. I tried stock tune and then restarting truck same issue. I'm currently at camp and go 2 hrs home tomorrow.
ideas ?

 

Pull the trans dipstick. What color is the fluid? Does it smell burnt?

 

I did a flush about 2 years ago, checked fluid when I stopped. level , color and smell perfect. still nice and pink

 

anybody else ?

 

Mark is THE "go-to" for transmissions... Is the OD light flashing? Is the transmission the original one that came in the truck? Do you have any way of checking for codes while away from home?
Try getting under the truck and make sure that all of the connections to the solenoid pack and transmission position sensor are not loose.

 

no flashes OD LIGHT .I was looking for it.
no way if reading codes up here.

I'll get under truck

 

Have you checked to see if you are low on tranny fluid? I drove a 2005 Cummins work truck for a bit that suddenly started doing what you are describing. You had to let off to get it to shift into 2nd and 3rd. It was low on fluid. I added 2qts and it was fine until I got it into the shop to fix the leak.

Even if it is not leaking currently, it may have puked some fluid while you were towing.

 

Ok , so to update on this..
Drove truck home from camp with lighter trailer.. (my dad pulled what I brought up home)
So was very light load of boat and trailer..
Truck pulled totally normal for about 1 1/2 hours or what seemed until the trans reached about 170 degrees and started to create shfting issues again.

What I have noticed is that this might be a torque converter issue. Truck will drive along in what I believe to be first gear and while speeding will grab RPM quicker then it should and then continue to climb until I back off or pedal throttle.
It also seems worse when going uphill or more load and shifted normally while going downhill..

Likely time for a new transmission and new this day would come.

I would still like to hear thoughts on the matter

thanks

Kyle

 

This is a long shot but I'll throw it out there.
When I had a fuel pump fail due to a wire issue, low fuel pressure and the resulting low power caused similar shifting issues with the transmission. It's definitely worth checking before spending the coin on a new transmission.

 

Just borrowed great code reader from a buddy..
Code is P0732 - Gear 2 incorrect ratio.

BTW - the dipstick fluid color is still good but does now smell burnt..

Ohh and just driving the truck 10 or so miles each way back and forth to work, it hasn't happened since..
Then again , the truck is unloaded.

Kyle

 

That code confirms it is having problems shifting to second gear. That could be a sticking 1-2 shift valve or a damaged intermediate clutch.

 

What would you recommend ?

Kyle

 

Pull the valve body out and see if the 1-2 shift valve is sticking. If it isn't, chances are you need a rebuild.

 

pulled it out and there is some gunk around shift valve corners. how would I clean this ?? bottom right is a slightly different and is indeed sticky, which one is the 1-2 shift valve ?

 

it seems to be the line press modulator that doesn't move like the others. (from my further research)
does anybody know if they are supposed to move similarity?