mandingo32

Sorry in advance for starting this war. I've been reading through threads on this and the opinions are all over the place. The problem is most of those threads were dated nearly 10 years ago. So I'll start a fresh war...

My truck is coming up on 165,000 miles. I have no way of knowing in the tranny fluid and filter has been changed unless I pull the pan. I'm reading that some have just dropped the pan, cleaned the pan and magnet and then added the 4-5 quarts of fresh fluid. I've read others state to flush the entire system, but people argue that could potentially tear up the tranny if it hasn't been flushed before. I'm racking my brain here. Do I drop the pan and replace the filter and fluid lost. Or do I do a full flush. And if I do a flush should I have shop do it. It looks easy enough to do, but if something does happen to the tranny and a shop did the flush it's on them.

Help me out here...

blupupher

iTrader: (2)

Say no to power or chemical flushes, those are the ones that cause issues.
A flush that uses the trucks built in pump to change the fluid is fine. Many shops have a machine for that, but it can be done at home also (let me find a link).

I prefer to do a pan drop and filter change with a high mileage transmission that has never been changed. I added a drain plug to mine and have done a few more drains using that.

Another thing is your truck should have a drain plug on the torque converter, so you can drop the pan and change the filter, then drain the torque converter to get about 90% of the fluid out.

As for changing the fluid itself causing the transmission to fail, that is just a myth, if the transmission is going to fail, it will fail.
What usually happens is people have some issue with their transmission decide to change their fluid, then the transmission fails, which they blame on the fluid change.

edit:
Here is the cooler line flush method you can do at home.

Here is a thread on adding a drain plug (although if I were to do it again, I would probably just buy a Dorman pan with a built in drain plug).

Here is a little article with a few pics of how to do it also.

Tackle

Drop the pan and change the filter. If it's remotely red and not an ungodly amount of shavings, I wouldn't bother with the TC either but it's up to you.

If you have the yellow/white plug in the pan when you drop it you'll know it's never had the filter changed.

You can't tell the condition of the trans or change the filter by doing a flush.

mbb

At very least , drop pan and change partial fluid, and replace filter. Get that metal silt out of pan. Shavings will indicate tranny health too. You should not have but a tiny amount.

A dealer flush will do nothing but potentially mess up tranny.

Theres no problem with doing a "flush" that replaces more fluid imo. If the fluid in there isnt burnt , dont worry about it. You can add fluid and pump it out return line until you have a lot more than 25% fluid replaced. You cant get it all. So many just drop pan every 20k-30k or so.

Transmission fluid is good at cleaning. Some people add a qt to engines that are burning oil to try to free stuck oil rings.

If the previous fluid was burnt and decomposed, there can be residues built up in worn spots that may be allowing things to seal and work. etc. New fluid or chemicals can clean crud out and tranny ceases to work. Note that tranny on last leg anyway if this happens. Damage was already there.

Same kind of thing can happen with high mileage engines. crud in valvetrain seals worn valve seals. Someone puts snakeoil motor flush in at oil change to remove sludge, engine starts smoking immediately because they dissolved the crud keeping oil out of the valves. Even a switch to synthetic could do this

mandingo32

That first link is what I was looking at as well as a video on YouTube that went through the process really well. There is no slipping and the shifting is fine. It was just making me nervous with all that I was reading. I'll at least drop the pan for now to see just how bad it is and go from there.

10thGenScab

I did mine in November... just a pan drop and filter replacement. I bought enough fluid to drain the TC too, but when I saw the good condition of the stuff that came out of the pan I decided not to. 194k miles and no problems, fortunately.

mh64

My vote goes towards just dropping the pan and replacing filter. I have 95k now, did a pan fluid and filter swap at 80k, its had a filter replaced before ( no yellow plug). But since that was the first time I had done it, im the second owner, I wasnt to worried about the rest of the fluid because it was still red and no burning smell. check the current condition of your fluid now and make sure you dont need all new fluid. I plan on doing another fluid and filter swap at a 100k. But you should be just fine with a filter and pan fluid change.

RbnFl

I change the fluid in the pan and torque converter. Why change only half the fluid? That doesn't make sense. When you change your engine oil do you only replace 2 or 3 quarts of oil.

Jbrew

Because you can't with a lot of these trucks...most of this generation in fact. Besides why change the pan and converter fluid without pumping the rest out real quick ? That's what doesn't make sense IMO. I wouldn't pimp a tranny fluid change...personally.

mandingo32

Been waiting on you to show up Brew.

I heard there is some money in pimping Trannys...