flush the transmission or not to flush?

[boonie]

i have 66,000 on my 94 C4 auto it,s time to service the transmission so what should i do?
1. take the transmission to the dealer and have him flush it?
2. remove the transmission oil pan, replace the filter + lost fluids myself?

 

[gregc11514]

Being a used car dealer, I have elected to "flush" anytime I do a service. I have done this to cars with 40k miles as well as cars with problems at 100k. I have never had a problem after flushing out a tranny. I would say more often then not I have noted an improvement in the operation of the trans.

I have to wonder how many Ford transmissions have been replaced because of that common shudder in overdrive when all it needed was a flush!

 

[vader86]

Get it flushed.

 

[ErnieN85]

Flushed is good..........however the filter change is extra, and should be changed also

 

[handstjg]

Flush it.
After watching my 86, with only 20k miles, go through the process it takes a lot of the worrying out of the equation. They just interrupt the hose going to the radiator and you get to watch the dark red fluid being replaced by the nice new red fluid.

The problem with changing the filter, gasket, and transmission fluids is the remaining old fluid in the torque converter. It has to be pumped out.

 

[RedRagTop]

boonie; Yes to the fluid/filter change. I had mine done for a very reasonable $70 Canadian including filter, gasket and dipstick grommet. If your C4 is a vert there is a bit of extra work due to the x-frame underneath but a very important overall preventative maintenance item.

 

[Blade]

Remember to always Flush!


If you do it yourself, watchout for the EPA Police!

 

[tobijohn]

Flush it.
After watching my 86, with only 20k miles, go through the process it takes a lot of the worrying out of the equation. They just interrupt the hose going to the radiator and you get to watch the dark red fluid being replaced by the nice new red fluid.

The problem with changing the filter, gasket, and transmission fluids is the remaining old fluid in the torque converter. It has to be pumped out.

How do you pump it out? Is this something best handled by a mechanic because it involves special skills and/or tools or is it something a person who has experience replacing the AT filter could do?

 

[Doug78]

The trans will pump it out for you. Unhook the return cooler line from the trans and put a piece of hose on it to direct it into a drain pan. Start the engine and let it idle in park. When the air starts bubbling out shut off the engine and put in about 4 quarts of trans fluid. Repeat this until the fluid coming out of the line is clean. Reconnect the line and fill up trans as you normally would when checking the fluid.

This is the procedure we use at the US Postal Service on ALL makes and models.

 

[tobijohn]

Thanks! Can I assume that if you immediately turn off the engine when the air bubbles appear, the risk of damaging the AT by running dry is negated? Also, can I assume any filter change should be done AFTER the torque convertor is purged?

 

[Doug78]

As long as the trans is in park you won't hurt anything as nothing is moving. The pump will suck the pan dry and thus will no longer pump fluid out, you don't need to shut it off the INSTANT that it starts to spurt, some off the guys I work with leave the engine running and add fluid until it goes clean, but we have a bulk delivery whereas you would be using quart bottles.

The "filter" is really just a screen to keep large pieces from getting sucked into the pump, the magnet in the bottom of the pan is the real "filter". If the gasket is leaking replace the screen, clean the pan and magnet, and replace with a new gasket, if not you can leave it alone.

 

[tobijohn]

Thanks!