I have 25,000 miles, original fluid. About to tow 750 miles (about 8K lbs.). Should I change the fluid before or after? Probably doesn't matter but I'm **** about this stuff. Thanks.

 

If the fluid in there now looks and smells good, do it when it is more convienient.

 

I would change it now. You're pretty close to the end of it's service life, and now you're going to put quite a bit more strain on it. Good fluid will help prevent damage.

 

with all due respect... you're kidding right?
you have 25K on that fluid right now that's in it and you say you're **** about this. If you really were it would've been changed every other engine oil change, like every 10-15K.
Do you honestly think another 700-800 miles is going to make any difference?
come on...change it, you're way overdue.

 

As long as the fluid still has a good "red" color too it, and isn't too dirty, than I wouldn't worry about it. I have 38k on my original fluid, though I plan to change the fluid in the pan before I get to 40k, and it still looks ok. After I change it though I'm going to go to every 20k - 25k "pan fluid" changes.

 

To each thier own,I have over 400,000 miles on my tranny and I only change it every 100,000 and it still looks and smells good.I also use the tranny magnets to help, and the stock donut has very little metal on it.
Dusty even seen my tranny with the pan off and he was impressed!
I'm not saying do as I have done, but by no means are you going to hurt anything by going another 700 miles.

 

Not saying you should do this either... but as #2 said.... 700+ miles isn't going to make a difference one way or the other.

My tranny (48RE) didn't have it's first service until 208K, per what my tranny shop could tell. I bought it with very high mileage and was willing to put another tranny in it for the price I stole it for. When I got it at 207k it had a very hard shift out of park issue (big bang sound when taken out of park... all other gear shifts were smooth). Seller assumed the worse and that the tranny was toast... So, I got my '05 for a steal of only $7,500. Drove it to my tranny shop and $150 later in parts (half a valve body) it was fixed and is smooth. My tranny shop said they could tell it had never been serviced before in it's life (at least the pan had never been dropped). And for an '05 that isn't that unbelievable except mine had 208k on it already. Accept for some worn out fluid they said everything else was in order and showed normal signs of wear.

Now that I own the truck I wont be waiting for another 200K before it gets serviced again.... but I sure wouldn't sweat much under 40K!

 

I agree with many of the others on this issue. I have an '03 w/48 RE and change every 30K. As long as it smells good and looks good I don't touch it until 30K and I tow 14K lbs. on some hard mountain pulls. At 25K if it looks good and smells good tow the load and change afterward or later.

 

Now........you really going to risk a tranny for a few bucks?