I saw a post from 2003 where a guy asked about changing his trans fluid when the truck was cold, but he never got a good answer. Part of his quote was…..

“Everything I have read says to change the tranny oil when it is hot. My 'baby' is the third vehicle in a 2 driver family and sits for days at a time. When I fire her up, it always takes a bit for the fluid to get pumped back into the TC and I suppose the VB. Seems to me it would be best to drain it after a few days since all of the fluid has naturally drained out of those parts.

Like him my truck is a 3rd vehicle and will sit in the garage for a week at a time and when I start the truck it does take a min to get the fluid pumped up. If the truck has been sitting that long wouldn’t more trans fluid and contaminants be sitting in the pan waiting to be drained out. Would it be a good idea to just change my fluid after the truck has been sitting in the garage for a week or longer? The last time I drove the truck I had it on the highway and up to full operating temperature so once I parked it many of the contaminants should drain into the pan right? If I start the truck up to warm up the trans, will I be spreading those contaminants back into the trans? Any thoughts…….

 

Good point!!!

I'm subscribing to this thread.

 

If you have the option for for it sit for 3-5 days before you service the trans that's great, I bet a lot of people would like to be able to do so but it not an option for most of us....

 

Yea I rebuilt an 87 Tersel 2 years ago that only had 52k on it and a blown motor, thats what I use for my daily driver so the truck can sit when I dont need it to tow or haul.

Anyone else think this is a good/bad idea?

 

Never gave it a thought, sounds good to me. You can be our beta tester. Let us know. Got to be better than a flush job.

 

As the fluid sits, particles drop out of suspension and end up at the botom of wherever they are. That leads to a high concentration of particulates (crud) sitting in the low spots.

When the fluid gets warm and circulates, the particles are held in suspension. When you drain the fluid, you get those particles out of there.

 

I've been thinking about adding a +4 quart tranny pan to my truck with the magnet on the drain plug. There are a few on the form that think the stock tranny pan works as well as after market stuff and is a waste of money. All you get is 4 extra quarts of hot oil anyway.

I think the magnet in the bottom of the pan, after reading this tread may be worth while. Change pans or mod the one I have. ?

Dave

 

I'm on the stock pan team. I pull a 12K fiver with serious wind resistance. My trans temps never get close to high, usually about 170 on the road, 180 in the city. If I wanted more cooling, I'd put another trans cooler in, not a deeper pan.

And you have a magnet in the pan. If you want more magnets you can stick them in the pan or even on the outside of the pan.

 

I think you nailed it right there!

 

Always hot. Maybe if it was a manual, cold would be ok, but not on an auto. Even on my G56 I take it out on the highway and run it until its hot (which takes a while) before I drain.

 

If you want to let it set a few days, drain it hot, then let it drip for a few days.

 

Great point,covers both theory's. Get rid of the particles in suspension and then let it drain with the pan off.