Tune Up & Gas Milage

[wbandyjr]

My truck gets about 240 miles on a full tank..I changed my front diff and transfer case oils,My rear diff has a small leak so they left it alone.I also had my tranny flushed with wynns flush, I had my fuel system flushed with wynns,I also had my radiator flushed.My tires were aligned, balanced, and rotated..Now i get like 320 miles on a tank full.O ya i also cleaned my k&n air filter..My truck seems to ride in 2 modes..The mode i like is when it has all that power behind it..The second mode sucks.I would accelerate fast and the power just isn't there and on the highway in this mode is the egg smell..A comment from a friend one time was "thats really cooking" So whats up with this and the good milage...
How important is it to fix the rear diff?
How about changing the eight spark plugs?
Dealer says i need swaybar bushings?

My last question. When you are having tranny failure can your milage improve before breakdown?

Thankyou

 

[section525]

Back when my 5.0 was stock and new I use to get 302 miles per tank. So 320 is pretty awesome. I doubt the increase in mileage is due to a tranny going out. That wouldn't really make sense.

But what I was gonna say was back when my truck was stock.. I could tell a difference in the way it ran with different octanes and brands of gas. Will your truck switch 'modes' on the same tank of gas?

Change your plugs. It's a world of difference if they're old.

Fix your diffy. Its easier than replacing it when you run it dry on a road trip to AZ in the middle of nowhere with your GF *****ing at you.

 

[wbandyjr]

The running modes switch periodicaly..I use the same gas and the cheap grade (87)..The last time it ran great it lasted for 2 or 3 tanks of gas..They want $100 to put a new pinion seal on the back diff.,And 60 to replace the swaybar bushings.Not sure what the plugs will cost tho.. Thanx for the input

 

[lonestar]

My rear diff has a small leak so they left it alone

Who is they? They need some help. If it is leaking, that is the time to do something. You have to pull off the cover anyway. Just pull off the cover, drain it, put in new diff cover seal, reinstall cover and fill.

This is why!

Its easier than replacing it when you run it dry on a road trip to AZ in the middle of nowhere with your GF *****ing at you.

Sounds like you been there before?

 

[Robert]

The $100 price that he mentioned was for the pinion seal as he mentioned, not the cover gasket.

 

[wbandyjr]

The garage i went to didn't want to change the oil because the pinion seal has a small leak..The new oil would make it worse with the cleaners and what not in the oil..I am saving up a few bucks so i can have new plugs put in and the swaybar bushings replaced.Was quoted $330