'96 Dodge Grand Caravan Fuel Consumption

[Crash321]

'96 Dodge Grand Caravan ES, 3.8, 180k miles
I used to get 19-20 mpg in town & 24-25 on the hwy, when the trans. went out in it, the mileage dropped considerably. Now I struggle to get 16 in town, and 20 on the hwy. No idiot light is on, I have checked for codes, and there was none. This van runs great, has all kinds of power, but I gave it a tune up anyway, Plugs, wires, filters, oil change. With no change, I'm kinda stressed. I know it can do better, I just cant find the problem. Any suggestions would be appreciated.
Thank You

[neon_rt]

Did you have it rebuilt or replaced?
If you had it replaced, maybe the new trans has a different gear set in it (3.63,3.75,3.94,4.06) vs. the original 3.42 set. This could account for some difference.

[Crash321]

The Trans was rebuilt by qualified tech. I have noticed that as i'm speeding up, it wont lock into 4th until about 45 or above which gets the rpm's up to 2.5.-3. Used to be 30-35. I have tried starting out in 3rd. and shifting later. Thats works big with the R's, but still leaves the the mileage way down.I have also noticed the MPG guage. As I speed up the mpgs read 2-3 mpg till I get up to speed. Used to be much higher.
Thanks

[MT-2500]

Take the trans back and get it ckecked out.
Is the TCC lockup working?
Make sure everything is up to par on it and check your engine running.
MT

[Bel-air 454]

did they reprogram the computer? on most transmissions the computer has to be replaced with the transmission.