Winnebago adventurer

I'd definitely start with the speed NOT reading correctly.

The transmission shifts electronically based on several inputs, one being speed. If it's losing that, it does it's best to shift based on other inputs (like engine speed) but may lock out overdrive.

1 seems to be fine, tran shop looked at it and of course it did not have the issue probably cause it wasn't driven under a load. It seems to take about 30 miles as long as there is a grade and happens when I am pulling a load. Tried to duplicate the issue w/o the trailer and I drove around aimlessly trying to get it to fail.

2 speedo does NOT read correctly
3 shifts normal
4 yes at the beginning of a trip, until I hit a hill or a bit longer miles so it might be heat related
5 no light on
6 n/a
7 2000
8 after going up hills and have a decent load it will to shift into overdrive so I am stuck going pretty slow to keep the RPM's down
9 I believe so
10only service work done was trying to fix this issue. Shop replaced a cable ... Apparently not the issue
11 I hear/feel 4 when OD is working
12 no slipping that I can feel
13 not sure
14 assuming it is accurate in OD it sits around 2200-2500

I really appreciate everyone's effort in helping me resolve.

Fairly common issue for the 4L80E you have. (It's a '99 right?) My brother happens to have the same issue in his '01 class C with the 454 right now. He's at the Googling the problem stage, lots of info out there.

I did some Googling too. One thing I found was a list of questions that helps guys like me with some mechanical knowledge understand the issue:

1. Fluid level okay while running, warm, level surface.
1a. Fluid color and smell
2. Speedometer reading correctly
3. Shifting normal/hard?
4. Shifting into OD okay?
5. Any service engine light?
6. If SES light on, what codes do you have?
7. Model year?
8. Describe symptoms?
9. Does the engine come up to full temperature?
10. Any service work recently done that may contribute to your issues?
11. Does the TCC lock up (or how many "shifts" do you hear)?
12. Are you experiencing any kind of slipping?
13. What type of rear do you have?
14. If you have an accurate tachometer, what is the RPM at 55 or 65?

You don't have to answer all the questions, but the more you can answer, the better luck you'll have getting some help. These come after we know exactly what it is of course, but I think we know that. '99 454 Chevy P32 chassis (which would have a 4L80E transmission).

What year is the chassis? Is it a 4 speed transmission?(chevy) or 5 or 6 speed transmission(Allison)?

Correct , it seems that once I put some stress on it "load" I can't get it back into overdrive going down a hill or anything. It's not cable related as I had that replaced.

Thank you

If you are under load you do not use overdrive.

Very good point

Workhorse chassis 7.4 lt v-8

Unfortunately I do not know the make of the tranny, hoping someone may have experienced this problem and the make is not crucial

Thanks for the feedback

It would help to post the chassis type, engine type, and transmission...