I have a 95' F150 with the 4R70W 4X4. I was thinking of changing the tranny fluid since I bought it used and do not know when it was changed last. It has 101K miles on it. I've had 2 dealerships tell me that they do not recommend it over 80k miles because sometimes older transmissions have problems repriming itself. This sounds nuts to me. All oils and fliuds are meant to be replaced, but I wanted more info. on it before I do it. Anyone else ever heard of this??

 

I heard the same thing and I tend to agree with you, yes all fluids needs to be changed.

 

It's not that - the problem is that if the fluid was NEVER changed, then all the worn material has built up inside the transmission. The detergent in it can only suspend so much, so old fluid will allow small pockets of deposits to develop all over inside the transmission. If the fluid is replaced, the fresh detergent will break up the deposits, flooding the transmission with debris that can cause it to fail almost instantly. That's why many people advise against changing REALLY old fluid; if the transmission has been neglected, they figure you should just drive it until it dies and get what life you can out of it.

But I've had success on 3 vehicles so far by changing the fluid & filter (adding the HELP! drain plug kit PN65128 while the pan is down), driving 500-1,000 miles, and then changing fluid & filter again. This seems to flush all the deposits out without further damage.

 

without a doubt, change the fluid. imo

 

You will know right away if the fluid had never been changed because when the transmission is installed at the factory there is a off-white plug they use in the dipstick hole to ship the trans so it will not leak. So anyway, when they install the dipstick they just push the plug into the pan, so if the fluid has never been changed that plug will still be in the pan when you remove it!
I suggest changing the fluid, filter and draining the converter and while your at it drain and refill the tranfer case also but use regular atf mercon for the that.

clearity- mercon V for the transmission and mercon for the transfer case and never the twain shall meet unless the input seal to the transfer case is leaking.

Just my two disturbed sense(cents),

 

I have my F150 at Mr Transmission as we speak. Called them on the phone yesterday and told him I wanted the fluid and filter changed. Took it this morning and told him I was having shifting problems. He said exactly what Steve said. If you put fresh fluid with deterent in it all the junk and metal filings will break loose and go through the transmission - end of transmission.

After telling me he shouldn't change the fluid he dropped the pan to see what he could find. Now isn't that a lot like what you do when you change the fluid??

He showed me all the gunk and some sticky gooy stuff he said was transmission additive.

Anyway the truck is still there. He's going to pull the tranny and take it apart to see what's wrong. He's charging $259.00 for this. That goes toward the price of fixing it.

He says the longer I drive it like that, the more expensive the repairs will be. Guess that makes sense.

Boy I hate it when I have to turn my truck over to someone, but I sure can't fix the thing. I've got got reports from people who have had work done by this guy that he's honest and does good work so I just will have to hope for the best.

 

If I pull the pan and see the off-white plug then it was never changed, but by then I have no choice but to change it. Now I don't know if I should or not after hearing all this. I just don't like the idea of 8 year old oil protecting it. If there is mineral build up, why wouldn't the filter chatch it before the build up occurs?

 

Don't know the answer to that, but if that crud was on the filter, seems like it would clogg the filter big time. Since you already got it off I suggest you do what Steve said. Put fluid in it, drive it a few miles and then drain it again. I don't think I'd drive it very far. It's sort of a gamble. If you don't drive it far enough the gook won't get disolved and if you drive it too far it will damage the transmission. I wonder if Steve drove all three of those cars 1000 mi before changing the fluid. He knows way more about this stuff than I do so maybe he'll chime in with some words of wisdom.

 

I'm obviously no expert here, but the filter is not much of one, a couple layers of felt-like mat. Probably lets a lot of the "fines" get through. Dropping the pan and re-filling it will only add about a third of the total fluid in the tranny, so I wouldn't be too worried about the detergent being that active, as it is diluted by the remaining older fluid. Just BE careful that you don't over-fill it like my son did!

 

To do a total flush I have to seperate it from the engine right? How else can you drain the converter?

 

To clarify, you will not be flushing it. you are going to drain and refill the trans and torque converter.

to drain the converter, look at the bottom of the bellhousing and there will be a black rubber plug, remove the plug, use a flashlight and rotate the converter till you see a bolt. That is the drain plug for the converter. remove the pan and note any material there. clean it and reinstall it and the converter plug.

your transmission should take about 11 quarts, a filter and a trans pan gasket. Make sure you have a long narrow funnel for the refill. put in about 6-8 of the quarts slowly and start it up but no reving. check the fluid at 1/2 qt intervals from 9-11 qts each time running it through the gears for 3-4 seconds each then back to park. when the fluid level is right at the top of the cross hatch marks it is full. your done except the clean up.

the pan bolts are toqued at 107-132 lb/inch
the converter drain plug at 21-23 lb/feet

 

I didn't personally drive them - I did the first change and gave the owners instructions about the second one. 2/3 of them had no problem, and #3 had over 100,000mi on the original fluid & filter, so I don't think its failure is evidence of a flaw with my theory.

 

Steve, sounds like pretty good odds. Wish I had saw your a day earlier before I took it to Mr. Transmission.

 

I wonder if one of them auxiliary trans filters that uses a spin on oil type filter would help with removing the goo

I would think it would help unless it restricts the flow of fluid