[mrnickleye]

If the oil has never been changed, or you don't know for sure (red looking oil), I don't recommend the full flush service that a shop would perform.

If the oil is very very dark, and smells bad, it likely has over 80k miles on it, or has some clutches going bad (slipping)which killed it.

Cleaning out the trans with a machine may very well cause it to need an overhaul real quick.


I suggest the following method, which is less of a tranny killer for the high mileage, burnt oil ones.
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Just buy a trans filter kit from any parts store ($20-30).
Get a can of brake spray cleaner, a roll of teflon tape, a wire wheel (for drill motor), wire toothbrush, and a tube of silicone gasket sealer/maker, and 3-4 qts of Dextron III.

Drain the oil from the trans pan (remove the plug, save the gasket), then remove the pan, gasket, and then the filter.

NOTE: If there is a bunch of metal particles on the magnet (on bottom of pan), and/or LOTS of debri/muddy stuff on the bottom of the pan....plan/start saving $$$ up for a rebuild coming soon. A finger 'smearing' amount is OK/normal.
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Install new filter, clean off old gasket from pan with drill motor and wire wheel (or bench grinder with wire wheel on it), and then trans casing (with wire toothbrush if needed, and rag).

Brake spray cleaner works good for the 'final' cleaning of oil and stuff off all the parts, and bolts.

From experience, I strongly suggest applying a "very thin" (but complete) layer of silicone adhesive to both sides of the new gasket, or to pan, then gasket.

Lay gasket on pan, matching up the holes, then install pan onto the trans case. Install all the bolts finger tight. Then use the ratchet and lightly tighten them in a pattern that skips every-other-bolt. This will 'draw' the pan evenly to the case.

I always place the socket extension between my pointer and middle fingers, so as to not over tighten the bolts.

Make 3-4 passes (like torqueing a headgasket) to draw them down firmly, but not real tight.

**Remember, you have a soft gasket between the metal parts, and you don't want to over-tighten it, and squeeze it out much.

Now wrap teflon tape (stops it from tiny leak) around the threads of the drain plug, 2-3 x. Install plug and tighten very firmly.

Add 2 qts of trans fluid, then start the engine and let idle in 'park'.

Check the level, then shift into reverse, then drive, then back to park. Top up the fluid level. Done.

I recommend that, in a month or 2, drain the fluid (from the plug), and top back up. This will eventually change out all the fluid over a years time.

This method will be the least amount of harm you could do to the trans, and yet give you new oil.

After that, its up to you. Now I change out 2.5 qts every 6 months. It always stays red, and I don't have any shifting troubles.