MPG seems worse after fluid services

Currently I'm seeing less MPG on the heads up display and also last fill up down by 2 mpgs manually calculated as well.

Fluids serviced with drain and fill are transmission, front and rear diff and transfer case. Ravenol 75w-85 for rear and front diff and Ravenol 75w for transfer case. Toyota WS transmission fluid.


Is this normal? Since I bought the truck I've been averaging at least 13 MPG. Last fill up was under 11 and I only drive half tank before filling it up.

 

Mine got better after fluid change. Not sure what would cause it to get worse

 

I’ve recently changed all 4 as well and have not noticed a decrease. I used same lubricants as you except I used Valvoline 75/90 in diffs. I’m currently sitting at 15MPG according to MIDS

 

Odd. Anyways I'll just monitor it. Hopefully it gets back to the 13 average that I get driving City only.

Maybe I was idling too much while doing all the service along with the coolant change. I don't know.

 

Update. Last fill up is back to 13.59. all is good

 

Typically with coolant change you idle alot to purge air. With these engines, even a slight increase in idling destroys mileage.

 

That night be it. I was worried there for a bit, that I did something wrong.

 

Had a company 01 ford f150 with the 5.4 triton. 300k miles. Would easily get 20mpg. They had me go in and get a trans flush and then found out all fluids and filters were due (only thing that had been done to that point was engine oil) and had me change everything from bumper to bumper. Mileage dropped to 15 after that and never came back up.