2004 Chev Silverado 5.3 engine 4x4 107,000kms....I have transmission problems......at 98,000kms. the transmission started to slip....I had warranty so the truck was taken to the garage and the transmission was replaced. At 103,000kms. I put the truck in grear and the transmission started slipping...I stopped the vehicle immediately...put it back in drive and the transmission started working again....brought it to a GM dealer...said there was a little too much oil in the tranny so they removed a little and said drive it....no issues until today....left a stop sign and coasted down a slight hill as the road was rough...started to apply the gas and the transmission was slipping, would not go into gear....stopped...took it out of gear and when I put it back into drive....transmission started to work again......could someone please suggest what is wrong with this transmission.......I do not drive this truck very much as we drive the car but this transmission issue is very concerning.......Thanks

 

I don't think it's a slipping issue more of a hydraulic issue with the valve body and accumulator pistons loosing pressure. Valve body issue or a seal is blown inside the transmission which causes loss of pressure in the necessary places. Which is why when you take it out of gear and put it back in, the pressure returns. Does it slip in all gears? For example, if it starts to slip and you put it into manual 3rd, does it feel like it's slipping still? Perhaps a UD hydraulic circuit malfunction. I don't think this is your typical worn out slipping clutch issue though.

Transmission will need to be rebuild or at least disassembled to fix.

 

Sounds like a possible sticky value body.
Tranni fluid flush and a new filter if it has already slipped and burnt any of the bans.
Smell the fluid to see if it smells burnt

 

It is such a shocker when the transmission starts to slip that I have never tried changing gears etc.....I just stop and it starts to work again.....could there be something electrical.....external causing the problems.....the transmission that they replaced in my truck had the identical issues, started to slip, only happened the once and then worked without issue right until it was replaced.......
Could this be a problem....find that when I start driving the vehicle and put the truck in gear, each time it makes a roaring noise like the engine fan is running??? noisy what I believe is the transmission making the loud roaring sound and after driving it for a couple minutes the noise goes away...
Thanks for your replies........hate having issues with a vehicle

 

Just made a trip to Winnipeg hauling a ATV in the bed of the truck and a 6 wheel argo on a trailer.....always use the trailer towing function when pulling a trailer.......got to Ashern (300 miles) and had to coast to a make a sharp corner into town and when I applied the gas, transmission started slipping......put the truck in neutral and then put the transmission in 3rd gear...drive....nothing..just slipping.....coasted to a stop and put the truck back into drive and the transmission started to work again........could it have something to do with an electrical problem when using the trailer towing mode or something to do with coasting.........came back from Winnipeg hauling an empty snowmobile trailer so I did not use the trailer towing mode..........no problems with the transmission?????

 

I suppose it could be related to the tow/haul mode, because it increases the line pressure running to the clutches. Honestly sounds like a leaking piston seal. Trans will need to be diagnosed again with a gauge most likely.