As I understand the conversation, no service was done between the time the warranty repair was done at 38,000 and the fluid change about 90,000 miles later at 135,000. Since there was no flush done between those times I would also recommend a pan drop, filter and fluid change, (no flush). It's my understanding, flushes are not recommended if the transmission has high mileage or has gone more than 50,000 between flushes because the flush can dislodge metal fragments not caught by the pan magnet or trapped in the nooks and crannies where parts don't move. Fragments are then circulated into the moving parts and friction surfaces and quickly wear them out. Unfortunately, the 4T65E transmission is the weakest link in our cars and are often done at 150,000. Hopefully not, but this could just be the beginning of the end of your transmission.

 

You can find all kinds of videos on youtube about changing and flushing transmissions. Look for some of them it will give you a lot of useful information.
I think that if you have a full flush done now either DIY or find a shop with a good reputation, it will definitely be good for your car. After that you could probably get by with just a fluid and filter change every 30,000 miles. Unless you are in hard conditions such as extreme hot environment, mountain driving, high speed driving or towing then the fluid and filter change will get you by.
One thought I have when people ask about flushing a tranny is would you change engine oil then dump 2 quarts of the old oil back into the engine?

 

Your buddy gave you a bum steer. Always change the filter, it costs next to nothing and perhaps and hour and a half of your time by the time you put it up on ramps etc. Careful not to over tighten the pan bolts when reinstalling them.
I used my granddaughters old plastic sand box to catch all of my trucks transmission fluid, (my Monte's has a drain plug). Also I would just upgrade to the DEX VI rated fluid, only costs you about $15 more for a far better fluid. I like ChiBi's advice, drain the fluid, change the filter, add some DEX III drive it for a 100 miles, Drop the pan, drain the fluid. Now add the DEX VI this time to the correct operating level.

I change my tranny fluid about every 5,000 miles, a pan drop / fluid replacement. Use Redline D6, about $12 qt x 9 qts= $108, NAPA filter $20... cheap insurance for me...

Here is how you can add a drain plug to your tranny pan and stop having a mess, see link below...

http://www.ebay.com/itm/B-M-80250-Un...VTD6I-&vxp=mtr

 

Good to know, thanks. Hoping it's not too late mile-wise to drop the pan and change the filter. I really want this transmission to last.


Is this an alternative method to draining out the old fluid from the transmission cooler lines?

Do you recommend that I replace 1 quart of the transmission fluid I put back in with Lucas' Stop Slip? The transmission is not slipping, but like I said above, I want this car to last.

Also, are you a frequent driver with your MC? 5,000 miles is quite the difference to every 30,000 miles or so for a transmission fluid change.

Did you drill the 1/2" hole in the center of the pan? Would I have to replace the gasket for this drain plug, similarly like the oil pan drain plug?

 

At 90,000 miles on the transmission you should be fine changing the filter now.
You can definitely do the dilution method and change the fluid then do it again in a hundred miles. That will flush most of the contaminates out, especially since it sounds like you changed some of the fluid recently. It wont be a substitute for a flush, but comparing the cost of a shop doing it to doing it yourself it might be a good option.
There are other methods to getting the lines and the cooler drained, the best is a shop with a pump designed for this. I have seen guys that will disconnect the lines and let it drain. I have seen guys that will use air pressure to flush the cooler and lines but I don't like that method. I do not think these newer cars have the drain plug in the torque converter. The older cars we would just pull the converter plug and let it drain.
I would not put any additives in just yet. See how it acts with the filter change, you might be surprised. I don't like any additives in a transmission. If I ever do suggest additives I stick with Lucas or a product called doctor tranny. The doctor tranny works great if your transmission shudders, but I would try it without first. Lucas is a good product though if your inclined to put something in. As far as the service intervals, whatever your comfortable with. Certainly changing every 5000 miles will make your transmission last a lot longer. Myself the 100 plus dollars I personally go longer.
I think there are kits available for adding a drain plug to the transmission. It will have instructions on how to install the kit.
After high school I went to college for automotive tech, then I had my own shop for about 5 years. I got out of it because I never had any free time. I was always busy with someone elses junk, and the mechanic thing was getting too hard on my body. My hands were tore up, my back was wearing down and it went from a fun hobby to a job so I got out. One time I did have a firebird brought to me for transmission work. It would not go into gear, and when it did get rolling it wouldn't shift right. I knew the kid didn't have any money so I started with a transmission flush. I don't remember how many miles it had, but it was over 100,000. After one flush it started working better, so I ran it 50 miles and flushed it again. That time it worked like new. A dirty filter will change the pressure in the valve body and in the rest of the transmission which effects the way it shifts. By changing the filter you will restore the pressure to where it should be.

 

I always like to drop the pan, replace filter, reinstall pan, fill with fluid, disconnect the return line and start it for a second to force the system itself to bring the old fluid out. Repeat and add new fluid until new fluid is coming out of the return line, then reinstall return line and check level again.

 

These two methods sound good. I think I know a guy who has a pump designed for this, so I will ask him. Although, disconnecting the lines seems like the easiest way for me to go as a DIY situation with no pump.

Very interesting. Good to know, thanks! I will definitely be replacing the filter, then.

This sounds like the best way for a DIY situation. How can I tell which line is the return line? Any chance there are pictures showing which one is which?

 

This should help you:


at 1:26, it's the "striaght" line. I think these montanas used 4t65e as well.

I'd grab a piece of hose and put a hose clamp to it and put the other end in a clear milk jug to see where you're at while you're doing this. Also put some cardboard down for any drips.

Yes this is also my favorite DIY method. Just keep in mind the fluid will cycle very fast so we are talking a very brief time to have the car on.


Edit: Actually where the video is currently you can see the return line.

 

You can also flush the cooler and lines with an aerosol product.

Here's how:
Here's the product I use:

 

Thanks for sharing that, I did not know there was such a product out there. As soon as the weather warms up a little I am going to do a flush on my daughters Mustang. I might give this stuff a try!