Tranny fluid change but..

[TBJ]

I bought my car is May, it has 177000km on it now and I want to switch from the regular transmission fluid to a synthetic (we have very cold winters, sometimes in the -50C). Most driving is done in a small city and it would take quite a while to make a gradual transition using the drain and fill method. I think the best option for my vehicle is a transmission flush but I would have to bring it to a service station, lube place, or mechanic to do. I assume they would have a machine to do this, my question is what do I need to know that:
- they know what they are talking about
- what is a good machine and how can I tell if its any good
- how long may it take
- are there any treatments I can add to the transmission before the flush that would aid it with deposits (similar to the engine oil flush concept)
- is it possible to do a flush on the rear differential

This is all I can think of to ask, any helpful comments are welcome

 

[Big Jim]

If you mechanically inclined you can do a trans flush by yourself. The "hose in a bucket" method. Disconnect a trans cooler line at the radiator. Tickle the ignition switch to determine the direction of flow. Attach a length (about 6') of cheap plastic hose from your local hardware store and drop the other end into a bucket. It may be useful to have an assistant. Remove the dipstick and insert a transmission funnel. Start the car and fill the transmission at about the same rate as as old fluid is squirting out. Stop the engine if needed so you don't get too far behind. It will not hurt to get three or four quarts behind. It may help to calibrate the bucket first by using a quart jar and filling the bucket with water, marking the bucket with each quart. Since you are in Canada you may prefer to use liters. When you are nearly finished the old fluid coming out should be as pristine the new fluid going in. Anticipate running two quarts more than the capacity listed in your owner's manual. More if the old fluid is particularly cruddy. No pre-flush chemicals are needed.

There are so many fluid exchange machines out there that it would be impossible to tell you the merits of them all. Any of them are no better than the person using them. Most shops use flush machines furnished by their "snake oil" providers. The snake oil companies make their money from the additives used. The pre-flush "emulsifiers" may provide a slight benefit and will do no harm if properly flushed. The other additives are not really needed.

If you really want the pre-flush chemical, try to buy it directly from a shop and then flush it yourself. The shop may not want to sell it without selling you the entire kit, including the after flush additives.

However you handle it, good luck.

 

[Gary Allan]

TBJ

Why do you need to take it to a shop? Are you in an apartment/condo situation that would prohibit you from working on it yourself?

Otherwise, BIG JIM has your solution. Takes very little time to exchange fluid via the cooling lines. You can even make a pan drop a whole lot less messy by just running the sump dry and then removing the pan and filter. Other than that, it's running about 120% of the normal dry capacity of the trans through it. Reconnect ..top up ...be happy.

I'd do Auto-Rx before doing the exchange with a pan drop (in the manner I described) ...I'd also, if you're so inclined, suggest some form of auxiliary filtration. A magnefine fits on any car.

 

[Donald]

The cleaners (like BG) might do some good, but they are only run in the AT for 20-30 minutes. The additives in fresh ATF will do a much better job in cleaning over the next week or three than any cleaner run for 20-30 minutes. The AT conditioner should not be needed with good ATF.

The conditioner (and maybe the cleaner) may mess up a UOA as one does not really know its VOA.

 

[Gary Allan]

Just to clarify "running the pump dry" should read "until it stops pushing fluid". Hopefully no one will stand there with no fluid being discharged with their finger up their nose ..chatting with the locals. When the pump starts to cavitate, you turn the engine off ..either drop your pan then or refill ..repeat.

ATF is mainly a COOLANT-lubricant. It's the same for high volume blowers/compressors.

 

[Rhymingmechanic]

If you're talking about the vehicle in your signature, it should have trans and differential drain plugs, and possibly an external, spin-on ATF filter. Maybe some Subaru owners can clarify the setup.

 

[TBJ]

Forgot about that filter, will have to look into it.