whitecrystal1

If you don't know how it was treated it might be best to just drop the pan and change the filter and pan fluid. If the torque converter has a plug drain it too.

KAH

I would like to talk a bit more about draining the torque converter.

We all obviously have our personal preferences. My opinion is to
not drain it, leaving some of the used fluid in the converter rather
than changing it.

Others say to open a plug and drain the torque converter.

Not being a professional mechanic and only working on family
vehicles sort of limits my exposure to the problem. I always
change the filter and sometimes the gasket. But have never
drained the torque converter. I have a few times, merely cleaned
the filter very carefully if it was in good condition but usually
change it.

But suppose you do drain the toque converter. When you then
start the vehicle, with the torque converter empty, will this
momentary empty torque converter cause any problems ?

Ken H.

Kattumaram

[quote=KAH;121801]I would like to talk a bit more about draining the torque converter.

We all obviously have our personal preferences. My opinion is to
not drain it, leaving some of the used fluid in the converter rather
than changing it.



I always have the torque converter drained (AODE/4R70W), but resist flushing the transmission to purge the torque converter when a converter drain plug is not present (A4LD and similar transmissions) unless the tran is nearly new and completely devoid of any contaminants in the system. Forced purging can loosen debris in an older gear box and severely screw up the valve body.

FYI: I took my '97/4R70W to my local shop for routine transmission service. The technician dropped the pan, turned the flywheel to get access to the TC drain plug, removed the plug, drained the TC, replaced the plug, replaced the filter, reinstalled the pan with a new gasket and filled the transmission with Chrysler ATF+4.

Standard procedure at this tran shop is to use ATF+4 in all Ford transmissions.

Improvement in shift quality, smooth and firm, due to the ATF+4 was immediately noticeable when I drove the truck home.

ATF+4 will outlast Mercon V by a factor of two, so the next tran service will be in about 60K miles under normal service conditions.

wakonako

Where is the torque converter access plug?

Kattumaram

The AODE/4R70W TC drain plug access is through a hole about two inches in diameter at the bottom of the transmission converter housing.
Remove the rubber plug; locate the drain-plug by turning the flex-plate (flywheel) with a large screwdriver engaging the ring gear teeth; reinstall the plug with a proper thread sealant.

KAH

The AODE/4R70W TC drain plug access is through a hole about two inches in diameter at the bottom of the transmission converter housing.
Remove the rubber plug; locate the drain-plug by turning the flex-plate (flywheel) with a large screwdriver engaging the ring gear teeth; reinstall the plug with a proper thread sealant.

But let us go back to my original question, please.


IS IT REALLY NECESSARY TO DRAIN THE TORQUE CONVERTER ?

In my opinion, draining the torque converter
can cause more problems than it is worth.

For my purposes: drain the fluid, clean the pan, maybe change the gasket, always change the filter and never drain the torque converter
and live happily ever after, once you refill the transmission with new fluid.

Your comments, please.

Ken H.

exitwound

Before I re-joined the ARMY to come to flight school I worked for a transmission manufacturer in the R&D department for years. My question is why would you not change the fluid in the TC when you were already down there changing the filter. The more old fluid you get out of the system to replace with new fluid the better off you are. As long as the truck isn't started with zero fluid in the trans. then you will have no problems hurting anything. Just make sure when everything is drained and new filter is back on and pan is back on when you fill the trans with approximately the same amount of fluid before you start the engine.

KAH

The more old fluid you get out of the system
to replace with new fluid the better off you are.


I guess it is a question that will never be agreed upon.

My idea is based on assuming the fluid in the TC is in resonable
shape. Since there are no products of combustion such as in oil, nor should there be any moisture hopefully the fluid will not degrade over
any reasonalble period of time then why bother.

Now if the pan was filled with nasty, badly contaminated, burnt fluid
then I would agree with you.

I think it is also a function of what you find in the bottom of the pan.
If I found a bunch of shavings and foreign material, then I might just do
the TC.

Ken H.

exitwound

The oil in the TC is the same oil that circulates through the rest of the trans. And heat/cold cycles are what break down the oil over time. Provided the oil never gets too hot or too cold then the oil should last a long time. Since it is really easy to extract 90% of the oil in the trans using common tools in your driveway why would you want to mix 6 quarts of new oil with old oil when you could take a few extra minutes and replace almost all of the oil with new oil. Too me it's a no brainer.

Kattumaram

If the torque converter can be drained, drain it. If you will not or cannot drain the converter, then decrease the time/mileage interval of transmission service to maintain a decent level of fresh oil in the unit.