...THEN I checked the ATF level. 2 quarts low???
All is well again but I'm curious as to where the fluid goes. I've had to add ATF a few times before yet there are no drips anywhere I park. I've had the truck on a lift several times and there is no leakage anywhere.
Strange. I guess I'll just have to check the fluid level more often.

If a 4x4, the fluid could be getting into transfer case, causing that level to go way up. If not, make sure there is no heavy leaking at trans cooler-radiator etc

If it is a 4x4 ,Any of the transfer cases I have seen on these late model trucks usually have their own seal and the output housing of the transmission has its own seal and there is a passage for leaks to get away , I wouldn't think it's possible to leak into the transfer case. The transfer cases are very small in capacity also usually 1.25-1.5 quarts.
If it continues to leak fluid , you may consider adding UV dye to the fluid to help locate the leak.

Sorry, I forgot to mention that it is a 2wd truck !

Strange thing: It happened again today. I started the truck after work and a few miles down the road at a stoplight, it started off in 2nd gear. At 55 or so, I noticed that it didn't upshift to OD. I stopped to check the fluid level and it was right in the correct spot. Fluid is clear red and smells new. My commute is 92 miles each way and I knew without OD I'd need to get gas to make it home. I shut it down and restarted after refueling. Afterwards, the transmission was back to normal. I never got a
MIL, no codes, nothing. It is odd that a restart somehow reset "the clock" or however you'd describe it. At times the truck has felt like it starts in 2nd gear. This has been since the first year that I've owned it. I'm at 260,000 miles and aside from regular fluid and filter service, the transmission is original. I called a local wrecking yard. They have 8 of these 545 series units in stock ranging from $375 to $1050. The most expensive one came from a 19,000 mile truck.

They don't go into od until 67 mph.

Checking in neutral? Not sure if the newer trans are still like that.

The dipstick is stamped with instructions to check in neutral.
OD in this truck has always engaged well below 67 mph. I've felt the rpm drop and seen it on the tach as low as 50 mph.

What gears/tires do you have and what rpm are you at 60mph?

The truck has a 3.55 gear with 305-40-22" tires, I'd estimate the tires at 31-32".
At 60 in OD, it is around 1400 rpms. It will hum along there on flat ground.
The truck seems to like to screw with me on this. It occurs sporadically making the problem difficult to diagnose and solve.

Yep, just wanted to make sure 'cause these things are double-overdrive.

Sure like to know why the heck I have to wind my '07 up to 67 mph to get top gear? Every time, makes no difference. Otherwise it will stay in od 1 at 2000 and burns fuel like no tommorow. Get it into od 2 and it's 1600 rpm and mileage goes way up.

Even has it listed as 67 in Superchips advanced transmission stock tables.

Mine is a 5 speed auto. I thought some Mega Cabs had a 6 speed auto?

From Wikepedia:


Basic RFE operation[edit]
The fully electronic control is accomplished by the Transmission Control Module (TCM). Depending on year and application, it can either be a stand-alone module or integrated with the Powertrain Control Module (PCM). The TCM uses data from various transmission and engine sensors to control transmission shifting. The transmission operates the solenoid pack to change hydraulic flow through the valve body to various clutches in the transmission. The solenoid pack is mounted directly to the valve body; its connector protrudes from a hole on the left side of the transmission. On the 45 and 545RFE the hydraulic control system design (without electronic assist) provides the transmission with PARK, REVERSE, NEUTRAL, SECOND, and THIRD gears, based solely on driver shift lever selection. This design allows the vehicle to be driven (in “limp-in” mode) in the event of an electronic control system failure, or a situation that the Transmission Control Module (TCM) recognizes as potentially damaging to the transmission. On the 68RFE, fourth gear is used for limp-in instead of second and third.

This might explain things. If the trans is designed to still operate in reverse, 2nd and 3rd in the event of an electronic system failure then I must have an electrical gremlin. The truck did feel like it lost first and overdrive. I did not know until today that it IS double overdrive with a 4th gear .75 and a 5th of .67.

It's confusing, it has a first, two seconds, a third, then two overdrives. At some point they just went from calling it the 545rfe to a 6 speed up until the 8 speed was made available.

At any rate, it's worlds better than the RE I have in my '01.

Trying to adjust mine with a Superchips Cortex I bought, but having some programming issues with Superchips at the moment......

This morning it happened again while on the way to work. I shut it down to "reset" it and it worked fine for about 2-3 miles, then the MIL came on, the trans dropped down 2 gears and the rpms went up to 3100 at 70-72 mph. The MIL code read 0750, Solenoid pack.
I drove back home and checked a few things online. The symptoms indicated that the solenoid was failing or had failed so I checked YouTube to see how to change it. I had to drain the pan, pull the filters, remove the valve body and swap in a "rebuilt" solenoid pack. It was $240 with a $200 core!
It is all back together, the code was cleared and it all seems great. There was next to no grit/debris in the pan, the magnet only had a very thin film of metallic paste. I've been good about trans service.
I was impressed at how easy it was to swap out. I've always looked at automatic transmissions like "voodoo science" but this was a nice victory.

Nice!

Job well done

With you on that one but my thinking is more like " Past here Thar be dragons ".... LOL .......

Thanks, guys. I am not one to embrace new technology but stuff like YouTube really helps. There are all sorts of things that I have learned from other gearheads from that site.