AW4 starting to shift late.....

It is going on 20K since I have changed my tranny fluid/filter and my 87 AW4 (170K) is starting to shift late between 1 and 2 and 3. It climbs up over 4K RPM; which I never usually get to even passing on the freeway. I just replaced the 10 amp fuse under the dash and installed / calibrated to 82% a new TPS with no avail! I have also cleaned / re-lubed the underhood connections with dielectric grease. I know that when I changed the fluid ~2years ago I never got all the old fluid out. Is it possible to get all the old fluid out without taking it to one of the shops with the "flushing machine" and dropping ~ $80? Can I just unhook the return cooler line and start it up as long as I make sure the sump never gets dry until it looks to be pumping out clean fluid?
Fluid Still looks pinkish/red not brown, so I know it is not burnt fluid!
Any other suggestions??

Have you checked to see if your power/comfort switch is working? How about the kickdown cable? That affects shift points too.

I see from your profile you have a 87 XJ. You said you recalled the TPS but how old it is it and how many miles on the vehicle. I am thinking you have a worn out replacement of the TPS may be in order.

The power/comfort switch will cause the shift points to move up if you are in power mode. Just rock that switch on the dash untill the light comes ON when you push it into power with no delay and OFF when you switch to comfort. You may need to cycle the switch a few dozen times to get the contacts inside to self clean.

There is a cable from the trans to the throttle body. It is the cable which goes over the valve cover. You will want to do a seearch on Throttle valve (TV) linkage adjustment. It covered in Haynes and Chilton. I am looking at the Haynes transmission section. Between the archive posts and an aftermaket manual you will figure it out.

The AW4 does have a drain plug on the trans pan. If you want just start draining out ATF every engine oil change. It right at 3 quarts of ATF. Just start doing that and you will have a the fluid constantly renewed. What ever Dextron you use make sure it has the GM cert number on the bottle, there is a TSB from Jeep out saying to use only certified dextron.

I would do them in this order:
* TV linkage adjustement
* Make sure the light on the power/comfort switch comes ON at the same time the switch is placed in POWER position
* Replace the TPS and calibrate it. The multimeter will work but when I did mine that way the dealer mechanic told me the next time the TPS was wrong but he adjusted it for me. Using the test set if best but a mulitmeter is better than nothing. I found the mulitimeter method does not take in account the voltage drop in the wire back to the computer.
* start chaning ATF every oil change.