Broncomanjoe

I replaced my tranny and trans case in the fall and I added 2 quarts of lucas to it. Now that its winter it seems like im getting worse gas mileage than i did last year and i also just bought a K&N air filter .. does anybody know if by having lucas in it will decrease the fuel mileage when its cold out? Also I haven't driven it for more than 10 or 15 miles at a time so the fluid never even has time to warm up.

JJ1983

I have used the Lucas transmission fluid additive in one of my older trucks (C6 transmission), and it did not affect the mileage. Could it be that the winter is affecting you mileage slightly (colder air temp means denser air)? just thinkin here....my truck does a little bit worse in the winter than the summer.

Kattumaram

The Lucas additive does make the tran fluid a bit more sticky; the slight extra drag might reduce fuel mileage a little, but I think the real culprit on loss of fuel mileage in cold weather is rather simple: The torque converter clutch will not engage until the tran fluid reaches a certain minimum temperature. Even here in sandy, I mean sunny, Florida the chilly weather keeps the TC clutch from engaging for quite a while. The difference in mileage with and without the TC clutch engaged can be as high as 20%, at least in my experience.

FYI: My Lincoln TC has an "instant econ" display. On a cold morning, say 50F, the car must run for about three miles before the tran oil temp gets high enough to let the TC clutch engage. On flat ground at 50mph without the clutch the econ reads 22-24mpg; when the clutch engages the econ goes up to 28-31mpg....'nuff said.

JJ1983

Going by my edge programmer on my truck, the converter locks up at exactly 132F EC temp, not a degree under in normal driving conditions. My truck has to get to at least 132F for the TC clutch to lock up.

Broncomanjoe

Thanks I know the cold weather reduces mileage but it just seems much worse this year. But like i said i never even give the thing time to heat up everything i do is within 10 miles. So i guess I'll deal with it and maybe take it on a long drive and see what happens.