Most owners manuals recommend changing the auto trans fluid and filter at 100,000 miles. In my opinion, this is foolish. Every 2 years, or 25k makes more sense to me. Once a year, if the car is pounded hard.
There are 2 ways to go about this. Shops have a machine that taps the cooler line, allowing for a comple swap of the 10 or 11 qts in the trans and converter. Pan does not need to be dropped for this type of fluid swap. However, the filter should be changed. Be sure the shop does this after the fluid swap.
The old fashioned way is often done by the backyard mechanic. Pan is dropped, filter changed, pan and magnet cleaned, and approx 5 qts of fluid to fill it. Only 1/2 of the fluid is changed because the converter has no drain plug. The old fashioned way suits me fine, as I do my maintenance on a regular basis(every 2 years).
A couple of things to know:
Use the recommended fluid. The latest Dexron verion is correct. Avoid "universal" fluids.
No additives should be added tech tip on this subject in the future.
I like to pump the cold fluid out thru the dipstick tube with a pump. It is available from Harbor Freight for $5. Handy item.
After removing the filter, the fat o-ring gets stuck in the pump bore. Remove this carefully, without scratching the bore.
New o-ring is installed on the new filter, smear vaseline on it for lube, and firmly push filter in till it bottoms.
Spitshine the inside of the pan, clean the magnet and reinstall magnet in the pan in it;s square recess(round on the pre87 units)
Reinstall the pan gasket dry, or a slight, thin coat of vaseline only.NO GREASE OR SILICONES((rtv) ARE TO BE USED!
The pan rail has a servo dump hole near the gasket edge. Do not plug this hole with grease or silicone and the trans will burn up.
Finally torque pan bolts to 100 inch pounds. Do this twice before filling trans with fluid. A week or so later, crawl under and torque it again.

 

Nice work on all the tranny tips and info.

 

Thanks! I whipped them up during breakfast

 

Great tip!
The shop where I work has a tranny flushing machine and after watching some flush jobs, it's absolutely unbelievable how dark some fluid is that comes out during the flushing procedure Customers come in with 100K miles on their car and the old ATF looks like used motor oil.

Our machine can be filled by bottle with any type of fluid so it can service any type of tranny that may need a specific fluid. It has connector lines that simply attach to the cooler lines so nothing is cut to get the work done.

25 to 30K mile changes are very reasonable and the cost of the service is well woth it compared to a tranny replacement/rebuild.

 

Pete,

I like the method of removing the Trans outlet line at the radiator.

Run the car and watch the fluild come out into a bucket.

Fill more fluild into the dipstick.

Any comment on this method ?

Vic

 

Vic,
I have always been nervous doing that. The actual friction lining on a friction disk is approx .015. I have always been scared to run them without fluid. Especially the oem frictions. I can blow the lining off them with air pressure. They are so fragile when not in fluid. If you use that method, I would only do 1 qt at a time rather than 3 or 4 at a time.