Transmission oil change 2000 GMC 2500


I have heard various opinions on the necessity to change transmission oil. Anyone care to comment?


The only important comments are the one’s wrtten in your Owner’s Manual. The folks that wrote that are the definitive authority on your vehicle.


Drop the pan, change the filter and refill every 25k and your transmission will be happy.



I assume you mean the fluid in an automatic transmission and I side with Transman on that issue.
If your owners manual states that the fluid should not be changed until 100k miles, or never, then ask GM if they’re going to guarantee that transmission if it drops 6 months out of warranty . Not likely.


DO IT!!! I own a '99 Tahoe with 130,000 miles and I’ve been religiously changing my tranny/coolant every two years. The only thing I’ve had to replace since owning is fuel/water pump; to this day, my tranny still shifts and runs smoothly as the day purchased. My point, maintain fresh fluids and that monster of yours will last 'til the end of time…


Well said! The owners manual normally gives 2 sets of intervals, one for towing or taxi use and one for normal driving. My Toyota says it needs a fluid & filter change at 60,000 miles or 72 months, whichever comes first. GM promotes low maintenance at your expense; they only want the unit to pass the warranty period; you will own it a lot longer! I would change fluid & filter and make necessary adjustments every 50,000 miles for normal driving and 25,000 miles when doing trailer towing or carrying heavy loads. I would also have an auxiliary tranmission cooler for heavy towing. It is a small investment to make; my last GM car (at 19 years) had had 4 fluid changes when I sold it and the transmission still functioned perfectly. I have never needed to overhaul a transmission in the last 40 years, of which I had a camper for 30 years.


I wholeheartedly concur.

That’s why I gave each 4 stars. Why not 5, you ask? I figure there’s ALWAYS room for improvement, no matter the subject. Heh heh heh

I change mine every (approx) 25k miles too, as I tow a travel trailer on 4 long trips each year.

BTW, I don’t have to use the ‘tow/haul’ feature in my '02 Tahoe (4x4 5.3L (285 hp) with a 3.73 rear end) either, although it is recommended I do so (by other rvers).

When my local tranny shop changed out the fluid and filter the last time (126k miles) I had a very pleasant surprise.

No fluid discoloration or burning and no discoloration of the gears visible. Wonderful.

By not having to activate the feature, the engine turns over at 1900 rpms at 65 mph rather than 2400 at the same speed with the feature engaged. I get a constant 13.5 mpg towing with a steady normal coolant temp.

Not towing? I don’t know as I don’t use it as a daily driver.