The boys down at Firestone were telling me I need to change my tranny fluid on my truck after they balanced and rotated my wheels. The manual says 100k for normal maintenance. I have 71k on the truck right now. Any opinions on if I should go ahead and get it done now or wait? Also, how reliable is the oil life monitor that gives you % left of oil life?

Oh yeah, ditto for the transfer case

Oil life monitor is calc'd by RPMs driven at, and a bunch of other things that give a decent view as to when to change it, but can't factor everything.

Whatever the manual says 5k? 7k? should be followed.

As for the trans fluid, they're just trying to upsell you. Plus, you'd want to dump/filter change/fill, not "flush". Your following the manual is correct.

[This message has been edited by BigRobSA (edited 5/7/2014 2:17p).]

The question is, do you feel like spending money on it? You're not voiding a warranty or anything by not doing it, but your transmission might appreciate it if you did.


Also, you may have a different change interval if you're doing towing, off roading, or any other kind of driving that would be stressful to your transmission. You may want to consider your driving habits and take that into account.

Also, if it's a change and not a flush, that's probably something you can do yourself (though it can be messy depending on your vehicle).

Yea that's what I figured. I still have another year on the warranty left. Don't do any towing but did drive up and down the mountains ~15 times this past ski season.

There are 2 main camps on this

1.) Don't EVER do anything to tranny, just keep original fluid till tranny breaks, the reason behind this is that it keeps any "stuff" in the pan, or just hiding from getting stirred up. Lots of stories about trans failure following flushes

2.) Don't flush only change completely. Drop pan, wipe any metal or sludge from bottom and put all new fluid, filter and gaskets in.

2-A) Flush early and often every 30-50k

If you do your own service I suggest 2(along manual mileage suggestions) if you use a shot #1. With modern fluids, really no breakdown in trans fluid like the old conventional fluids.

Never touch the transmission fluid. Words of wisdom from my Chevy mechanic neighbor.

However, if you change it and the tranny goes out, you are still under warranty. Lots of stories of people with no tranny issues and then tranny fails right after being flushed.

Chevy mechanic went on to tell me to not do any extra preventative maintenance. Run synthetic oil and change it frequently. The newer trucks are made to last a long time.

Just traded in my 2007 Silverado with 140k miles. Replaced two evap sensors that caused engine lights to come on and had put one set of brake pads on it. That's it.

Never change it? Wow interesting, never heard that before. I checked into it and apparently the truck calls for a synthetic transmission fluid.

First. Never do business with Firestone
Second. Transfer case should have been changed at 50.

The manual calls for transfer case and transmission fluid @ 100k under normal use. I don't tow anything with the truck. Why would the transfer case need to be done at 50k under normal use?