Christcorp

I have a question I'm hoping someone has some insight on. I know how to check transmission fluid, but I'm a bit confused about my 2007 silverado 1500 4.8. This vehicle is new to me so I don't have a long history getting to know it's behavior.

Anyway; I normally drive the vehicle for like 10+ miles to make sure that it's nice and warmed up (Transmission fluid) and then I'll park and check it. Almost all of the websites, videos, forums, etc. I've seen mention that you want to check it at "NORMAL" trans operating temperature of around 175-200 degrees Fahrenheit. The problem is, the trans temperature never gets that warm. It's pushed around 170 once, but not often. I know if I let it sit in the driveway for 15-20 minutes idling after driving it, I can get it close to 180, but even that's hard.

My concern is; I want to check the transmission fluid accurately; especially before doing a drain and fill on it so I know how much I'm swapping out. But I don't want to accidentally be overfilling it. I know trans fluid expands when heated, and while outside temps might be 50 or 60 degrees, I don't want there to be too much in there when the summer temps reach 80's and 90's. Just wondering how to accurately check the transmission fluid if getting it to normal operating temperature of 175-200 is difficult to do. When driving, it averages around 140-145 degrees. I haven't driven it in the summer months yet, so I don't know what those normal driving temps are yet.

Any thoughts would be appreciated.
Thanks
Mike

Don Palmer

Cold temp measure, between 80 - 90 degrees F, in Park, engine idling 500 - 800 rpm, should be at cold check line.
Hot temp measure 180 - 200 degrees F, same operating conditions Hot band.
To assist in reaching hot temp, drive vehicle in 2nd gear no more than 65 mph until desired temp is reached.
Hope this helps!

Christcorp

Thanks for the reply. I appreciate it. This is one of the "RARE" times I actually decided to go with the owner's manual. I've been working on all sorts of cars for 40+ years but the silverado has some definite quirks. But it's a great truck. The owner's manual did state as you did, to check the "COLD" level at 80-90 degrees F. The hot however in the owner's manual said 160-200 degrees F.

As you suggested, I did drive around for quite a bit, but at the very best, I could only get the temp up to about 140 degrees F. I'm not a big fan of running a vehicle in lower gears, so once I get it warmed up to the 140 degrees, I leave it running in park. Every couple of minutes I run it through the gears. After a few minutes it will get up above the 160 degrees. I let it go a little bit more until it reached around 175-180 degrees. I then run it through the gears a couple more times, let it sit for a minute, and check it. I topped it off into the full range hot.

I'm pretty sure it's ok and in good shape. After driving it for a while and testing it when parked, the fluid looks good. Not foaming or anything, so I don't believe it is overfilled. At least not substantially. And it doesn't seem to slip gears or anything, so I'm sure that the level isn't too low.

Thanks again for the input.
Mike