Trans flush or fluid exchange on 1995 Explorer 4x4

I am getting ready to do a transmission service on the 95 Explorer 4.0L 4wd. It currently has 199K on it and I have a feeling that it hasn't ever had a fluid change. It has a 4 second delay from reverse to drive unless you put it in 1st or 2nd from reverse, in that case it goes right into gear. I am afraid of a tranny flush with that many miles and was thinking about doing a fluid exchange. I did this same thing on my car which is a 1990 Infiniti Q45. I followed along to the steps over at www.nicoclub.com that I'm a member of and it involved draining the fluid from the pan, put the plug back in, fill it with the same amount that drained out, start the car and let it run for 2 minutes, shut down and drain, repeat above about 4 more times. On the final drain, you drop the pan and change the filter. What happens is that your allowing the transmission sump to pick up the fresh fluid and return the dirty fluid back to the pan which takes about 2 minutes if the pump is good. In the end you should have 85% or more fresh fluid. I would do this on the Explorer but I don't know how long it takes for the transmission to pick up the fresh and return the old back to the pan. Has anybody tried this? I am also going to add an inline filter to the transmission.

Matt

Has anybody done a fluid exchange vs. a flush? How many quarts drain from the pan?

That was another concern of mine. So I guess I should start looking for another transmission instead?

drain the fluid and put in a new filter, dump in new fluid and your done.

SuRrEaLNJ said:

if its never had a fliud change with 200K on it then dont. its best at this time to leave it alone, as new fluid wouldbe a shock to the trans

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I've heard this philosophy before, but I don't subscribe to it, and i haven't had any problems yet doing fluid changes on high mileage vehicles... also there is no science behind it, it just sounds cool..

i say change the fluid.

it is possible that you're transmissions slow shift issue is a clogged up valve body/clogged filter (clogged filter reducing hydraulic pressure/volume to actuate clutches and bands) and in that case a new filter would fix the problem.

I would consider replacing the low/reverse servo O ring. These are notorious leakers when they get old and flatten out and it is easy to get at. That might get rid of some delay. Changing the fluid has never saved anything.

What is required to get to the o-ring. This will be the first time that I have dug this far into the transmission. As far as transmissions go, the most I have done on one is replace a filter screen and change fluid. Are there any special tools that I will need? I want to change out all 10 quarts if possible. I read that you can do the fluid exchange in your driveway but I'm afraid that it could damage the pump doing it that way. I know that if you were to do that on my car for instance, it would damage the transmission.

I was just reading another thread about adding a drain plug to the pan. I'm thinking of just draining the pan and topping off with during every other engine oil change and adding an inline magnafine oil filter. What type of drain plug do you recommend? Do I just drill a hole in the pan and use one of those self tapping plugs and just screw it in and out a couple of times to rid the shavings before putting the pan back on?

I just found out that it doesn't have a factory external transmission cooler so it is going to be a bit more difficult to install an inline filter. I'm going to have to cut the steel line and add the filter in between. I want to put it on the line that is returning to the transmission but I'm not sure which line is the return. Is it the line coming out from the bottom of the radiator or is it the top line. If it flows through the radiator in the same direction as the engine coolant then I would think that the bottom line is the return. Am I right?

I thought that I'd go ahead and send over what I posted. I didn't hear anything back about how to replace the reverse/forward o-ring so I didn't do it. I went ahead and changed the filter and put a drain plug in the pan. I then removed a section of the line coming from the transmission and added a Magnafine in-line filter. I took some pictures of the finished work. I found that 6 quarts came out of the pan, and that is after it sat for almost two days before I dropped the pan. I also found that the transmission holds 9.8Qts I believe that includes the torque converter. I am going to change the fluid again in 6,000 miles.

There are plenty of picture how to threads with low/reverse servo.

I don't think that is the problem anyway because I mentioned earlier that when you go from reverse to 1st or 2nd, it is instant. It is only delayed when going from R to D. If it was that o-ring, wouldn't it also be delayed no matter what gear you selected when going from R or is that o-ring specific to D?

I know this is an old thread but I just wanted to mention what I did that took care of the check engine light with the transmission. I ended up swapping the ECU out for the updated 95 model and it took care of it. Now I am just wondering if after all this time have I had the oil filter on backwards. I read somewhere that the return line to the transmission comes off the bottom of the radiator and I have the filter on the bottom line with the arrow pointing towards the radiator. It has been this way for around 15k miles.

Anybody have any ideas?

Disconnect one hose. Drain what leaks in a pan.
Put two bags around the openings (with elastic bands).
Bump the starter and see which bag collected the spewing fluid.
Reconnect and add new fluid to fill.

I have installed an external filter (I have auxiliary cooler) and that's what I did.
I did use a bigger FL1 filter (with remote screw base adapter), to minimize the pressure drop in the transmission circuit.