How do I change ALL of the transmission oil

[CGriffith]

I was wondering what the best way of changing all the oil in my auto is?

I have read about removing one of the transmission cooler lines and letting it pump out. How well does this work(how much oil comes out) and is it bad for the transmission? Common sense says its never good to run a pump dry but maybe it wouldn't hurt for a short time.

I have also heard of loosening the valve body a little to let the oil drain out of the converter. How well does this work and will it work on all auto trans? (I have to change the oil in the wife's GM next)



I do plan on dropping the pan and changing the filter but I want to get as much of the old oil out of the torque converter as possible because it is an used vehicle and who knows if previous owner ever changed the oil. I also plan on running synthetic and want as much of it in there as possible.

 

[catoiler]

You could take to a jiffy lube or the like,they have a machine that they hook into the cooler lines and it will flush all of it out. Bad idea to unhook the cooler line and let it run dry!It is about $80. 00 to $100. 00 for the job plus you don't have to get dirty!



Mike

 

[y-knot]

It really isn't all that hard to do, and I never liked Jiffy Lube or any other quick fix place.

First drop the pan and do what you have to (filter, adjust band, ect). Button the bottom back up and fill with AFT till it is showing full on the stick.

Get a one gallon bottle (bleach bottle,bucket, what ever, you can use a 2 liter bottle also), and remove the cooler line that is coming from the cooler. Get a 2-3 foot piece of rubber hose, big enough to go over the line's end. Slide the one end over the trans cooler line end, and the other goes in the bottle, bucket whatever you decided to use.

Look in your manual and find out what the system will hold, total capacity. Then figure what you already pull back in, and come up with a rough figure of what needs to be pumped out. Start the truck and let it idle,set brake and put truck in gear for about 5 sec and then park. If you have someone watching the bucket it is much easier, I didn't and had to repeat the 5 sec in drive motion a few times. I like to remove about 2 qt at a time, then top off the trany and repeat. The new trany fluid will have a bright red color to it, so this is also an indicator of then you have flushed all the old fluid out. Good luck

 

[snowracer69]

The problem w/ the pumps those cheap places use is that they back-flush your transmission, possibly pushing crap into the t/c out of the pan that you don't want in there!



Best way to get all the fluid out is to take it to a reputable transmission builder (DTT, ATS, ect. ) and have them put in an aftermarket t/c, v/b, billet shafts, etc! Then you can change the fluid out of the t/c with ease whenever you want! Course, it's a spendy initial investment, but the smiles it will leave on your face are well worth it.



Happy BOMBing, watch your step though, it's a slippery slope! I've gone from wanting a reliable 450 RWHP to now "needing" a minimum of 550.

 

[dremelts]

Originally posted by snowracer69

The problem w/ the pumps those cheap places use is that they back-flush your transmission, possibly pushing crap into the t/c out of the pan that you don't want in there!

I'm not sure that is necessarily always true. I brought a 1ton Dodge van in to one of the quick lube places to have the transmission flushed and they hooked the machine up to both trans cooler lines. The transmission circulated the fluid in its normal fashion and the machine put fresh transmission fluid back in the return line - so there was no back-flushing. They could regulate the amount of fluid being returned to the transmission so that the level on the dip stick stayed in the proper zone and the machine had sight guages so you could see the fluid coming from the trans. When the color of the fluid coming from the transmission matched the color of the new fluid being returned to the transmission they stopped the process.

 

[snowracer69]

I still don't think it's a good idea or way to do it. Ok, maybe for someone who has a stock transmission with absolutely no plans to upgrade it then, yes, it could be done that way... .



I wouldn't let you pay me for my DTT and then hook one of those machines up to it... I wouldn't let you waste your money like that. Like I said, once you've put the big initial investment into it, it's easy and cheap ($50 for me last time, for fluid and filter, plus 1. 5 hours time) and I get to make sure it's done and adjusted right.

 

[BillGotthelf]

Whatever you do DON"T follow the advice given by the so called expert in the last TDR issue. If you run the trans empty of fluid the seal in the TC pump gets trashed (only takes a few seconds with no fluid as it is always surrounded by fluid) and you get some big repair bills. By the time the fluid stops coming out of the hose and you turn off truck the seal is already damaged. The best way is the way Y-Knot said. Your trans holds between 12-14 qts of fluid. If you dump the pan depending on year you will drain 4-6 qts. Change the filter and add the same amount you took out, the disconnect trans cooler line at cooler (has worm clamp) and as the fluid drains out (4 qts at a time is easiest) shut off truck and add what you took out. Either change out the capacity of your trans or just wait till the bright red fluid starts coming out. Then just add what you need to top off.

 

[CGriffith]

Thanks for all the great answers.



I have always been a little scared of places like jiffy lube but if I found a reputable shop with a transmission flushing machine would they be able to use the amsoil I want?



I do like doing things myself so I will probably change it the way y-knot recommended. Any Ideas on how much mixing (if any) of the old and new oils occurs?

Also how do you tell which line is going to the cooler and which is the return?



Thanks,

Chelton

 

[BillGotthelf]

The two lines going out of the transmission going to the cooler-the bottom most line is the fluid out to cooler line-follow this to cooler and then you'll know.

 

[DZink24]

at the risk of breaking or cracking the return line (mine looks a bit pitted and corroded) how much fluid and how much time do you all think it would take to loosen the VB torx bolts and let gravity do the job? will the TC eventually give up all its hidden ATF?? i definitely want to do a total swap out, 60,000 miles and it has never been touched.