Home-made tranny flush idea

[rpellicer]

Here's an idea I came up with for flushing a tranny, and I thought I'd throw it out there for some opinions.

Take an old tranny pan and punch a couple of holes in it. One will be for a fluid drain, one will be for a hose. Remove the existing tranny pan and filter. Find a hose that will fit the pump intake where the filter was attached to. Make sure the hose is a generous length. Run the hose through the drilled pan and seal around the hole. Place the other end of the hose into a bucket of fresh tranny fluid. Run the engine until the fluid comming out the drain is clean, keeping an eye on the bucket of fresh fluid of course. The bucket of fresh fluid could even be sealed and pressurized to help the fluid get to the pump. When the fluid is clean, pop on a new filter and reassemble.

Think this would be a feasible idea?

 

[mtrdrms]

I like it, but it sounds like a lot of effort for a lazy guy like me.

 

[Chaddy]

I just pay 60$ every 15000 miles at my buddies tranny shop.

 

[sunnyc123abc]

couldn't you just unplug the tranny lines that go to the oil cooler, and do the same thing

 

[GEORGIA GABE]

OK, the way a trans flush machine works is by hooking up to the trans cooler line. that is where you would want to do it. Once everything is nice and warmed up you take the line loose and hook up to the feed line and to the return line. this will keep you from having to drill holes in a pan. I dont know how well it will work though. In a BG flush machine ( the one I have ) there is a cylinder with two bladders inside it. You fill up one side of it with 16 quarts of new fluid and it expands to fill the inside of the cylinder. then as the old fluid is pumped in it fills up the other bladder putting pressure on the new fluid and forcing in into the return. If that doesnt make sense tell me and I will take some pictures.
gabe

 

[guido666]

OK, the way a trans flush machine works is by hooking up to the trans cooler line. that is where you would want to do it. Once everything is nice and warmed up you take the line loose and hook up to the feed line and to the return line. this will keep you from having to drill holes in a pan. I dont know how well it will work though. In a BG flush machine ( the one I have ) there is a cylinder with two bladders inside it. You fill up one side of it with 16 quarts of new fluid and it expands to fill the inside of the cylinder. then as the old fluid is pumped in it fills up the other bladder putting pressure on the new fluid and forcing in into the return. If that doesnt make sense tell me and I will take some pictures.
gabe

That means there is probably no suction on the return, it is just a drain back to the pan. So you would have to be clever.

 

[Ned Kelly]

I got this tranny flush method off of one of the RV forums.

1. Drain you pan, install new filter, put pan back on, top off with ATF.
2. Disconnect tranny out line at the radiator connection point. Run a long piece of clear hose to a jug or pail.
3. Start engine, put it in 'drive' (foot on brake so vehicle doesn't move).
4. After a few moments old tranny fluid should come through the clear tubing and into your pail. Watch the tube. New bright red tranny fluid should follow after 1 minute or so. When you see the new fluid, shut down. Measure how much fluid you have in the pail to give you an idea of how much fluid to put back into the trans. You have done your backyard tranny flush.

I"ve done this several times and it seems to work well. I just buy a 20litre pail of ATF from Walmart.

 

[rpellicer]

This is the motivation behind the idea. The return lines from the cooler doesn't "suck" the fluid. The flush machines work by matching the fluid flow out the tranny to the flow back into the tranny. The machines I have seen so far work by either watching fluid flows and matching them, or using a cylinder/piston assembly so the outgoing fluid pushes an equivalent amount of fluid back in. Re-creating one of these systems for hobby use would be a hassle. Also, pumping out fluid then refilling as suggested, may cause the tranny to momentarilly run dry. My idea will 1) Minimize the engineering and fabrication 2) Minimize the risk of running the tranny dry (pump is drawing fluid straight from a bucket) and 3) Not require frequent stopping and re-filling. I'll be dropping the pan of my th700 this weekend, and will check if it can be done.

 

[dyeager535]

The pump intake is an orifice that the filter plugs into...the filter neck uses a seal to keep tight in the orifice.

You could probably make do by just cutting off the filter and attaching the hose to the leftover fill neck, but then you might end up cracking the plastic by trying to seal the hose as tight as it would need to be.

Once you had the fluid changed as you wanted, you then would end up dumping out the contents of the pan (clean fluid now) as well, right?

 

[rpellicer]

The idea was to have a second hole in the pan to drain the fluid as it flushed (into a bucket or something), then replace the filter and original pan. The modified pan would basically be there to control the fluid being flushed so there isn't a big wet mess. I like the idea of clamping a hose to the filter tube. Since it's not under pressure, it probably not going to need to be clamped too tight, it could also be rtv'd.