...and I don't mean the toilet. Anyone flush their engine or transmission themselves? I'm right around 40K. Before I change my engine oil and do my first transmission fluid change, I would like to flush. What do you use? How do you do it?

Any other info would be great. Thanks.

 

There is absolutely no need to flush an engines oil system. That is a BS procedure that quick lube places use to charge customers money. My son made that mistake and it cost him a timing set since the flush agent dissolved the fiber teeth on the timing sprockets. Engine oils contain detergent to clean the system and suspend the contaminants in the oil. As the oil passes through the filter it traps the particles. Yes the oil coming out during the oil change is dirty but it supposed to be, it just means it is doing its job. They love to show you how dirty the oil is and try to frighten people into getting the motors flushed. I suppose they flush their bodies out so when they crap it is clear or better yet they probably don't have to go since I know they are full of crap.
Auto transmissions are a different animal. In the old days some had plugs to allow the torque converter to be drained since about 90% of the fluid is in the torque converter. If they did not have plugs we drilled the converter case to drain the converter and installed a solid pop rivet that sealed the hole. I suggest you have a dealer take charge if you want the transmission flushed or just simply drain what little fluid is in the pan and change the filter.

 

KMHenry is right 100% i worked at Diamond Chevrolet in NC and they constantly sold transmission flushes. After doing research for years...this procedure can actually be detrimental to the mesh up of the transmission. Over time your gear mesh becomes better as things break in and those little miniscule pieces of metal end up filling in the spots your gear mesh doesnt touch. This does a little to help keep the gears quiet. Flushing all this out could leave you in the situation of gears making quite a bit more noise and just overall increased wear. if it is an Automatic just drop the pan...change the filter and the pan gasket and take note of how much fluid comes out and just replace it.

 

regarding the auto transmission, the only way to insure a complete change of fluid would be to open it up (drop and disassemble) and drain it all. A flush can't guarantee a complete change because of the intricate galleries. And a pan drain is at best a partial drain (about 1/3 on the 42RLE).

It is a pain in the @ss to drop the pan (messy, inconvenient) but some folks have installed drain plugs. I have one sitting on my bench for installing later this season. Others can speak to the various pumps available.

But whether you pan drain or pump it out, you only get out 1/3. So you have to refill then drive enough to mix and repeat the drain. Note that each successive drain removes some of the fresh fluid so it is not so simple to say that three drain/fills replaces the original fluid. (three drain/fills only replaces about 70%) The way dilutions work you never get to 100%. For that you have to do complete breakdown.

If you remove 1/3 with each drain and fill, it takes 7 drain & fills to theoretically replace about 94% of the original. ((2/3)^7)

It would take 12 of these 1/3 drain & fills to get over 99%. Serial dilutions never get to 100%.

BTW, Do you have an auxiliary cooler? Highly recommended !

 

Wow! I totally learned something. Thanks so much for the informative replies. I feel dumb asking this: Jiblet -- What's an auxiliary cooler? I've properly filled my engine coolant

 

The JK's transmission can run a little hot depending on what you are doing with it. So you can get an auxiliary cooler to help keep temps down.

If you search on B&M you will find lots of hits. There is a nice write up on installing the cooler. Very easy to do. I have one and it definitely helps keep temps down.

 

Oh, okay. Thanks!

 

I don't recommend trying to drain through an open cooler line. It is too easy to starve the pump and it would be damaged in a matter of seconds. If it gets damaged you might as well plan on replacing the transmission.