Transmission flush ideas, fitting sizes, and pan removal questions

When doing the poor man's flush, instead of pouring new fluid in through the dipstick tube, what about connecting a new host/fitting into the return line opening and putting that hose into a bucket with new fluid. Let the old fluid come out disconnected return line into a different bucket. That way you don't have to constantly monitor and guess how much fluid to add, and it can't get away from you.

I think you'd need a 14mm x 1.5 fitting to plug into the transmission then whatever else you want on the other side, proabaly a -6 AN and some tubing to go to the fresh fluid bucket.

What do you guys think?


Also, removing the pan to swap out the filter seems like a pain in the ass, but seems like I've read that you can support the engine with a floor jack and a piece of wood to distribute the weight. This will allow you to remove the transmission cross member/mount and get easy access to the pan? Is this the way to go?

The problem with connecting the hose to the return line, is fluid gets pumped though the cooler, not sucked back from. so it would empty the trans w/o filling it back up.

not sure about jacking up the engine. you could put a jack holding up the t-case though. that would hold everything up....

JoshRountree said:

When doing the poor man's flush, instead of pouring new fluid in through the dipstick tube, what about connecting a new host/fitting into the return line opening and putting that hose into a bucket with new fluid. Let the old fluid come out disconnected return line into a different bucket. That way you don't have to constantly monitor and guess how much fluid to add, and it can't get away from you.

I think you'd need a 14mm x 1.5 fitting to plug into the transmission then whatever else you want on the other side, proabaly a -6 AN and some tubing to go to the fresh fluid bucket.

What do you guys think?


Also, removing the pan to swap out the filter seems like a pain in the ass, but seems like I've read that you can support the engine with a floor jack and a piece of wood to distribute the weight. This will allow you to remove the transmission cross member/mount and get easy access to the pan? Is this the way to go?

Click to expand...

codyj86 said:

The problem with connecting the hose to the return line, is fluid gets pumped though the cooler, not sucked back from. so it would empty the trans w/o filling it back up.

not sure about jacking up the engine. you could put a jack holding up the t-case though. that would hold everything up....

Click to expand...

There goes my great idea. Thanks for clearing that up. One other thought, since you're filling the thing up through the dipstick tube, and the return line is disconnected, does any fluid drip out the hole where the return line goes?


Also I didn't mention in my first post, but the technique I've read about is to use the block of wood underneath the oil pan. Sure seems easier than trying to wrestle the transmission pan off with the crossmember in place.

Anyone have any thoughts about the block of wood and oil pan idea?

And what's the most accepted place to disonnect the return line from the transmission? At the transmission, at the radiator, disconnect the nylon fitting, o-rings, and replace those?

I just changed the filter and fluid for the first time which makes me way less than an expert but the crossmember was not in the way of removing the pan. Mine is a 2wd, is the 4x4 different? In reinstalling the pan I discovered belatedly that you can put several (or possibly all) of the bolts in the holes and the rubber gasket will hold them, greatly simplifying the alignment process with the floppy gasket. 5-90 suggested installing some studs which might be easier, particularly with a non-rubber gasket.

I did have a problem separating the two sections of the filler tube. A member (engineer from NC, I believe -- thread now lost) told me how to
solve that using a hose clamp.

JoshRountree said:

Anyone have any thoughts about the block of wood and oil pan idea?

And what's the most accepted place to disonnect the return line from the transmission? At the transmission, at the radiator, disconnect the nylon fitting, o-rings, and replace those?

Click to expand...

Don't jack up the engine - you'll still have the transmission and transfer case unsupported. Put a bottle jack under the transfer case body, raise just slightly, and you're good.

Even with "screw-holder" gaskets, I'll still tend to install a few studs to simplify things (you line up the gasket and pan, and you can hold them up with one hand while reaching for fasteners with the other.) For the AW4 pan, use M6-1.0x20m/m or x25m/m studs, with a small to no shoulder.

Where's the best place to disonnect the return line, at the transmission, at the radiator, or at the nylon fitting close to the radiator?





And, my idea about supporting the engine by the oil pan with a block of wood was for replacing motor mounts, I got confused...:shhh:

I just changed my tranny filter... IT SUCKS the worst job i have done so far. I didnt know the crossmember supported the tranny when i did it... scared the shit out of me... either way one of the crossmember bolts would not come out with out breaking so i left it in. Wasnt really hard to do with it there would have been a lil easy with it off if you can get it off the 4 bolts are worth the extra trouble just jack up the t-case and inch prior lol


as for the damn dipstick this is by far the worst part of the job. I couldnt get it off even with the damn hose clamp trick. So i weazled it out of there and with some PB blaster and a channel locks and vise grips ( I was careful not to bend or puncture the tube). I was able to finally twist it out. I replaced the old o-ring that was disgusting. Then replace the oil pan. I didnt think about sticking the bolts through the gasket prior to installation so i fought with everyone to get started. Broke the head on one. VERY LOW TOURQUE SPECS... but the hardest part for me was getting that damn dipstick to seat back in. I still dont know if it is seated all the way i just know it is finally not leaking from the joint anymore. I may RTV that joint just for good measure though. Anyway that was it. It took a lot of coercing to get the dipstick back in. HAVE FUN!!!

Wat about draining all the old fluid out , then with the drain bolt off still , pour a couple quarts of new fluid in and let that drain through, then put the drain bolt back on , and then add the proper amount of fresh fluid ?

I couldnt get the drain bolt OUT lol it just spun in the pan someone stripped it on the last change i recon... So i removed the pan completly and cleaned it in solvent tank.