MY 87, 700R4 works with no problems. Yet the Dextron II is very dirty and dark. The FSM states for a Pan Off, refill is 10 pints. Yet for a overhaul its 23 pints. That tells me that by just flushing the pan, you still have roughly 13 pints of old Dextron II still in there.

Doing a search on this forum, I read some suggest removing the top oil cooler line and running the engine to pump out all the Dextron II. The problem I fear is that Hydraulic Pumps really object to running with low or no oil. The FSM does not state how to really purge all the old Dextron II for a clean refill. Is my fear of pumping out all the old Dextron II thru the oil cooler line justified. If so, how then to purge it all out.

In 57 years of owing vehicles, this is the first auto tranny, dont want to screw up a good working unit.

Thanks
8Valve

 

I wouldn't sweat it. Here is my experience.

My 2004 Chevy truck: Did the oil cooler line off/new fluid in at 100k. Oil pump was so fast that I had no hope of pouring in enough new oil to replace that which was coming out to keep up. Started and stopped ~3 times, waiting until the pump spat air each time.

My 92 vette: The pump on the vette is a whole lot slower. You may be able to pour in new fluid to replace the fluid coming out as it comes, just pump into a clear bucket and go until you have taken out the correct amount of fluid (~13 pints).

Either way, I wouldn't sweat letting the pump pull air for a second. You know how getting tranny fluid off of your hands is. Just because the pump has started to suck air doesn't mean it is 'running dry.' It would take a little more time for that to happen.

Just set a clear bucket on top of a stack of boxes, stick some vinyl tubing (3/8" ID, cheap at any hardware store) on the upper oil cooler line, and let it pump until it starts pushing air. You'll know when it does - the tubing will jump around a lot. You'll know what I mean when you see it.

 

Ok, thank you. When you say the upper oil cooler line, is that in reference to the upper line on the radiator or the upper line on the tranny ? I have not yet traced out the lines to see where each goes.

Thanks
8Valve

 

I believe all you can get is Dexron III. You can take it to a shop which I believe they hook a machine up to the tranny lines to suck out the old fluid while new fluid gets pumped in. Though, its still good to drop the pan and replace the filter. I've read to stick with AC Delco transmission filters. And I used a Felpro rubber gasket so no mess next time the pan gets dropped.

 

I wouldn't worry about a "flush" or pumping the fluid out - I'd just do what was generally accepted to do before these quick-lube places figured out the flush could sound better and make them money... If you ever really stop to think about it - how can they get all the "bad" fluid out when they simply pump fluid out and then return clean fluid into the trans to mix with the old fluid that is still in the converter and the pan and the 'mixed' fluid then gets pumped up and out... Yes it will get a lot cleaner, but 100% exchange like some are claiming - I've got to say no way...

Anyhow - Drop the pan (yes it's probably going to be messy if it's your first time and you don't have a drain plug in there), change the filter, then if it were me I'd either install a deep cast aluminum pan with a drain plug or get one of the drain plug kits and install it in the stock pan to make future changes easier and a lot less messy... Fill with the appropriate amount of fluid making sure not to over-fill (checking often when topping up)

 

Ok, thank you. I understand and it makes sense. But, I wish I had 3 pedals on the floor LOL !!!

 

Might think about doing a shift kit in there while the pan is off - would make the automatic a lot more fun to drive and actually help it hold up to more abuse than the stock valve body calibration... TransGo HP line or Fairbanks would be my recommendation for an off the shelf kit.

 

I have been using a product made by International Chemical Corp. called Lube Guard and I swear it helps the transmission last and keeps the varnish and wear to a minimum. It is not a solvent which makes the seals swell like some of the Trans. RX treatments. I recently installed a Raptor Trans. in my '90 convertible with a 2400 stall converter and the operating temps are not high at all. I also use it in my '95 Astro AWD which has 170,XXX miles on the original trans. pulling a boat. The fluid after 100,XXX miles is still cherry red. A small bottle is all you need - 9-12 oz ( I cant remember how much is in a bottle)
Do what you want.

 

Thanks for your post. What is a shift kit, what does it do for me.
In 57 years, this is the first Auto. How difficult is install. In looking at the FSM, Group 7 which is the Tranny, it looks like a Back Box LOL !
Thanks
8Valve

 

Here's what you do. Drop the pan, change the filter and clean the pan. Button the pan up and fill with 4 quarts of tranny fluid. Disconnect the upper coolant line on the tranny, this is the return line. You can do this either on the tranny, or somewhere between the cooler and the tranny, whatever is easier. Put a hose on the end of the return line and put it in a pan. Start the motor. When 3 quarts of fluid has come out into the new pan, stop the motor, fill in another 3 quarts and repeat until 8 quarts or fresh fluid starts coming out of the line. Refill the tranny to the proper level and start racing.

 

Here's what I did.

1) Remove upper radiator transmission line, attach a clear vinyl hose and put the end in a bucket.

2) Start the engine and watch the transmission fluid pump out. After about 45 seconds or so, stop the engine. Mark the amount of transmission fluid that came out on the side of the bucket with a Black Sharpie.

3) Now, you can remove the Transmission pan and it should be nearly empty. Replace the transmission filter and reinstall the new gasket and transmission pan.

4) Empty the old fluid into your oil container. Thoroughly clean the bucket and fill with the same amount of new transmission fluid to the level which you marked on the side of the bucket.

5) Reattach the upper transmission line to the radiator and pour the New transmission fluid from the bucket into the transmission dip stick tube. Start the engine and recheck the fluid level once the engine gets to operating temps.

I replaced about 7 quarts with Mobil 1 Fully Synthetic transmission fluid which is more than half the capacity (total fluid capacity is around 10.5-11 quarts).

 

Thanks Guys, I understand and will do.
8Valve

 

In a simple explanation - All the shifting is controlled by basic mechanics, hydraulics and fluid pressure - thus if you want to shift quicker, firmer, or at a higher RPM something in the mechanical circuit has to change - shift kits can "re-program" the transmission to quicken and firm up the shift (some people call it 'crisp') to where there isn't the sluggish stock "comfortable" shift - the quicker shift actually reduces lag between gears and the slow apply which wears out the clutch friction material too - this usually translates into a longer service life for the transmission. In extreme cases you can get kits that convert the transmission into a fully manual shift that hits so hard it's like speed-shifting a manual faster than any human can and usually bangs the gears and chirps the tires - which takes away all automatic control of the gear selection (but they're reserved for the track as loosing the automatic features makes for a poor driving car...)

If you're fairly handy then the kit can be installed easily - they come with good instructions and you really don't have to understand why putting the part where they tell you to makes the changes you want - just know that they've done the research and created the instructions for transmission challenged home mechanics to install.

 

Great explanation, thank you. I understand.

8Valve

 

383Vette got it part right. "Here's what you do. Drop the pan, change the filter and clean the pan. Button the pan up and fill with 4 quarts of tranny fluid. Disconnect the upper coolant line on the tranny, this is the return line. Put a hose on the end of the return line and put it in a pan." (I am assuming it is a stock torque converter). Fill the pan with 5 quarts and have at least 2 quarts over the total capacity on hand. Have someone start the motor and leave it at an idle in park. Add fluid as fast as it comes out, and when the fluid changes to the new color, stop the motor and reconnect the transmission lines and check the fluid level and add what is required to bring it to the full mark. You now have done a 98-99% fluid change. The extra 2 quarts are for when the last of the old fluid mixes with the new in the torque converter on its way out. You can call me with any questions on this if you want. 909 795-1876. Dana

 

Dana,Thanks. I will be doing the flush tomorrow. I understand your instructions and will do as you instruct. I expect no issues, but thanks for your phone call offer of help.

8Valve

 

changing the filter is a waste of time/money...the filter does reduce junk recirc but if there is anything more than the few normal junk chunks in the pan your trans is near death anyway and a new filter won't heal it... 'might' delay complete failure for a short if complete obstruction is imminent, but again that much 'loose crud' in the pan only comes from all the wrong places.

unhook one trans cooling line at the radiator...unless you are certain that you chose the 'pressure' line vs the 'return', run drain hoses from both the radiator trans fitting and (now open) trans cooling line to a bucket...start engine, observe ends of drain hoses and shut engine off immediately when outflow stops...add 4 quarts new fluid to trans...restart engine and stop again when drain flow stops...repeat add/run/stop 3 more times...done.

no need to jack the car up/ crawl under.