Servicing tranny question

[webshot]

This is for a 88 GT AOD (119K miles). I want to change out the fluids, filter and all that good stuff. Is it necessary to flush the entire tranny? Torque converter and all? If so how is this done (torque converter)? Or is this something better served for a professional?

The car shifts and runs fine. I do have a rear seal leak. But I keep the fluids level. Also the new fluid going in full synthetic.

ANy advice appreciated.

 

[Mustang5L5]

With that many miles, if the trans has not been serviced regularly, then i wouldn't touch a thing. In fact a lot of garages will refuse to flush a trans with over 100K miles.

If anything you could do a drain and fill and change the filter so it leaves most of the old fluid in there. I would also stick with the same type of conventional atf.

What happens is a flush on a high mileage auto can flush out all the friction material and cause it to start slipping.

 

[RYC CUKR]

Mustang5L5 is on the money.

At the most I would drain the pan, change the filter and refill with new fluid. No flush and I would not drain the converter.

I did a full fluid change on a car once, Dodge Challenger with a 727. I had no real problems before I changed the fluid. About 100 miles later I was pulling the trans out because the fluid had leaked through one of the front seals because the trans had been overheated many times in the past and burnt the seals. The thicker burned fluid wouldn't leak but when I put the thinner new fluid in it didn't take long to end up with a huge cloud of white smoke under the car.

Pulled the trans and had to have it resealed, new pump, one new band, and a new converter put in it. That ended up being a $600 trans fluid change.