I've heard three different opinions...

The first is that it should be done at whatever the owners manual recommends. Very regular schedule, like oil changes.

The second is that it should be changed about once a year, before the weather changes (like before summertime..basically before it gets hot outside)

The third thing - I've seen some trannys go 100k miles without touching them. Now the school of thought behind this is that the clutches wear down, and the debris is still circulating with the fluid. This allows the tranny to still function properly. But then you go and change the fluid, the clutch debris is gone, and the tranny dies shortly thereafter because the clutches are toast. The tranny would have normally still functioned if you hadn't changed the fluid. Any truth to this?

What's the best route?

 

I thought it was every 20k miles.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER, NO CAT
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat
2:73 GEARS
Rebuilt 700R4, with manual valve body
B&M Megashifter, 5" Autometer Tach w/shift lite
Soon to be installed
3:73 Richmond Gears and 3" Hooker Aero Chamber
Corvette Servo & .500 boost valve
15.61@ 95.2mph G-Teched, 1-2 shift slippage, and just replaced a burnt plug wire
"There is nothing more addicting than speed"

 

I do mine around 30000 miles.


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro

 

I change mine yearly, as part of my yearly "college is out" major tuneup. It should be changed yearly; the 700r4's run hotter than other trannies, and that heat breaks the fluid down.

But yeah, I've seen long-lasting 700r4's myself... and have heard the same thing. Supposedly if you've never changed the fluid, you shouldn't start, otherwise the trans might die. Of course by this time the trans is probably shot anyway... it probably just buys the tranny some time.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

It depends allot on how hard (and not) it is used. For hard use you couldn't go wrong with 12K-20K. For normal use 30K-50K is alright. Just make sure that quality oil is used and that it is properly filled. Don't use ANY sealers on the pan. Proper torque of a cork and rubber gasket is 12 Ft/Lbs. The fiber is 16.