I finally got around to doing a transmission service on my truck. I did a complete fluid ecxhange, bucket method. I dropped the pan and changed the filter, and exchanged about 16 quarts.






Ready to start....





I tapped into the return line on the side of the transmission...





With a graduated-marked bucket, I can see just how much fluid has drained...






Not to bad considering the last service was over 70K ago...





Pan and magnet all cleaned up, new filter...ready to reinstall...







Oh yeah, just for good measure...




Quick video of the bucket set-up in action...

http://www.youtube.com/watch?v=_Xm3z...ature=youtu.be

 

Now I think I'll go "Have a cigar"

 

Very cool! I need to do this to my 4R75E soon. Do you have a pic of the line you tapped into? I'm not sure which is the return. Also, what was the total amount of fluid drained before you began refilling?

Yup, love the soundtrack to your vid.

Thanks!

 

On the 4R7 series transmissions, the return line is the one on top. In other words, on the side of the transmission, the two cooler lines are above and below each other, rather than side-by-side. The top one is the return from the cooler.

I would run it till just about 4 quarts were in the bucket, then stop and refill. Letting out 4 quarts before dropping the pan, there was less than half a quart in the pan when it came down...started off with fluid about right in the middle of the grid on the dipstick with a warm transmission.

 

Little hint:

Getting the cooler line off is relatively easy. Getting it started back once you're done can be a little tougher. I loosened the other end of it, where it goes into the thermal by-pass block, when I went to re-attach it to the side of the trans. This gives it a little play and wiggle room.

Once you get it re-attached and tightend down on the trans, then re-tighten it at the thermal block.

 

Yup, I know exactly what you mean. Thanks.

I think the thermal bypass on my truck may be sticking or not operating reliably and have been wondering about replacing it anyway. This may be a good time to do it.

 

Don't want to de-rail the subject here, but I have a question, what makes you think the bypass is getting flaky ?? Temp variations ?? Why I ask is that mine has started to act weird lately, it used to run around 150-155, now occasionally it runs 170 - 175 then will bounce back down. Could be mine is going bad also.

 

Yup, that's exactly what mine does, same temp ranges and all. It can happen sitting at idle, no relation to load, air flow, or ambient temp. Looking at the flow of fluid through the system, the thermal block seems like the most likely cause.

I'm not a trans guy though, and would appreciate hearing from anyone who's had this problem or knows of any other probable cause. Thanks!

 

I would say yeah, the by-pass valve is flaking out...or possibly the temp sensor itself is starting to read erratically?

It would be bad news if the thermal by-pass got stuck in by-pass mode...might cook your transmission. I wonder if there is some kind of fail-safe designed into these things?

 

Thanks very much for the responses, this may be the next thing on my 'to do' list.

 

Wurker: Have you figured how many miles you are going to put on the Magnefine before you change it out?

 

Hadn't thought about it. I think I am going to do another fluid exchange in 50K miles, but leave the pan filter alone on that one.

Maybe 25K on the magnafine? Do you know if there is an established consensus on the mileage for these filters?

 

With my sons truck in which the transmission will never be worked hard...Mostly highway miles...I will change the first filter after 20k miles and cut it open too see what the inside looks like...

If still clean and not a lot of residue? I will extend the next filter to 35k to 40K miles... Mind You-->This transimssion had 170K miles on it, with never one service before we brought the truck home... When I dropped the transmission pan for the first time, I was shocked to see the inside of the pan really spotless and just a little residue on the magnet... So I figure the first filter change will still be very clean... But I just want to make sure...

Now...If the transmission is worked hard most of the time?---->{Towing-Hot Rodding-Heavy Stop and Go driving}-I would replace and cut open every 15 to 20k miles... Then after seeing the results? You could make a decision on the mileage for the next filter change and future filter changes...

Above----->This is just what I would do.... Not Advice!

I figure I will not mess with the pan filter for another 100K miles... Though next summer I might do another flush before he leaves for his freshman year of college... I will change the Magnefine and add one of these---> To help some what with cooling and make future flushes even easier... Seeing how clean the bottom of the pan was after 170K miles, I really see no need to drop the pan for the next few flushes... {Just add a pan with a drain plug} and the transmission flushes are made very fast and almost mess free, with the addition of the Magnefine to the return line...

http://www.americanmuscle.com/mustan...81-BaseFitment

I will not change the pan filter though...

Just one more note: Your pan looked exactly what my sons pan looked like... I was amazed!

 

Cool, thanks for the info. I've been doing some more research on this and on my trans problem. Did you do the exchange with the trans warm/hot? Wouldn't the thermal bypass be closed if the trans temp was below the temp at which it sends trans fluid to the cooler?

 

You know, I wondered about that before I started, but it flowed fluid throughout the process. The trans was warm, but not hot. Maybe 150º.

EDIT: It's quite possible that I never exchanged any of the fluid that was in the cooler and lines beyond the by-pass valve. If it was in by-pass, it would just route the fluid right back out to the trans return. (In my case right to the bucket)