Hey guys, I just picked up a 2007 suburban 5.3 2wd with 170k miles for what I think was a good deal. I drove 900 miles from Odessa Texas to Havasu City Arizona. When I got to Phoenix the air temp was already at 101 at 830am. By the time I reached havasu the air temp was 105. I kept a close eye on trans temp and it got up to 212 at the highest.
I have 2 questions.
First, should I do a fluid change? I don't believe the previous owner ever did one and I'm very hesitant from the research I've read.
Second, should I be expecting a transmission purchase in the near future?
I inspected the trans fluid when I reached my destination and the trans fluid seemed dark and smelled burnt.
I forgot to mention I am not towing amd it's a 1500 so I don't think there is an external trans cooler

 

I bought a 2007 Tahoe with 4 wd ,150,00 miles 3 years ago.The first thing I did was to have the dealer drop the pan and change the filter.Tranys are too expensive not to do this, especially since you have no clue what the previous owner didn't do.I had the dealer do it because the exhaust crossover pipe is a little in the way and I didn't want to mess with it on my back in the driveway.I do change my 1999 GMC tranny oil myself since the pan is un-obstructed and drops straight down.I change the tranny oil every 50,000 miles I would also recommend changing the rear end oil also.Just my 2 cents worth.

 

Yes, I'd definitely do a fluid and filter change. Also, axle oil, u-joint and front-end grease joints, maybe the antifreeze as well. As long as the transmission is working okay, I'd run it until it doesn't. It wouldn't hurt to add a fluid cooler, but if you are using it light duty, you might not really need one, but overheating an automatic transmission is the number one cause of early failure.

 

Hello,

I have a 1999 Tahoe as you might be able to tell.

inrecently did a Transmission fluid flush after the gears were slipping all of a sudden. It was a hot day but no hotter than usual in the Texas summer. I’m assuming it was getting too consistently hot and went bad.

Regarding cooling fluid, is there a recommended fluid that you add to the coolant reservoir or to the transmission fluid, to help keep it extra cool?

 

Your 1999 is easy to change and if you have the dealer do it be sure to ask them to see that magnet in the pan, take a picture for reference to compare for the next change.Every 50,000 just have them drop the pan and change the filter and add 4 qts. or so of oil, no flush.Anyway,this is my procedure.

 

Thanks. I had a mechanic do it not there dealer. I’m probably the third owner of the vehicle which seems good considering it’s 150,000 miles now.

It had a flush and replaced the fluid.

Next time I’ll do what you mentioned.

Regarding fluid to help it stay cool, would I look to add anything or keep it as is?

 

I don't know of any thing you can add to the fluid to make it run "cooler".Maybe somebody else does.If you are going to do a lot of towing then maybe an external cooler.If it ain't broke, don't fix it.Just stick to a good filter and GM fluid.I don't run any additives and I check the fluid for being clear red once a week and make sure it doesn't smell burned.

 

Thanks!