will gas mileage vary that much?? on odw, someone said they got 24 mpg!!!!! i'm happy to get 18...if synth gives that much more, i may switch over...and do you need to run full synth or just partial??

 

By full synth, do you mean in the engine or engine + tranny + diffs + transfer case?

Fuel economy is better, but not that much better, so don't expect miracles. Maybe a 5% - 10% increase in fuel economy going synth in the engine, diffs & transfer case. Maybe.

 

I gained an average of .8 mpg.

 

by full synth i meant engine + tranny + diffs + transfer case. would there be any problems if i switched over now..i'm right at 93k miles...or should i just switch my engine over to synth..? thanks for all the answers.

 

Switching to synthetic is ALWAYS better. I am at 68K, and just made the switch. The benefits of synthetic:

Better gas mileage
Less wear
Longer oil life, thus increasing change interval time
Slight increase in performance
Better heat dispertion

The list goes on...

IMO, the engine oil pays for itself. My change interval with non-syn is 3K miles. With Syn, its 5K miles. Ends up paying for itself (if you buy Mobil 1 at Costco for $23)

 

I switched at 85,000 miles. No problems.