Flushing auto tranny in BJ74

[Joe70]

On my last wheeling trip i underestimated the depth of a hole and ended up being stuck in water over the headlights for about 15 mins. After getting out of the hole I noticed that the tranny wasn't shifting when it was supposed to. I checked the fluid and it was slightly pink and not translucent any more. Long story short, it's in my garage now and I'd like to do as close to a 100% fluid swap in the tranny as possible. Is this something that I can do at home or does it require special equipment to do properly? I was thinking that maybe I could disconnect both lines at the rad and put one line into a pail of clean atf and the other line into a bucket for disposal. Does anyone see any flaws in this? Any input greatly appreciated as I'm trying to avoid a costly bill.

P.S part of the long story involved needing to replace the alternator (seized) and starter (also seized).Trail was Fisher east

 

[peterb]

Joe
I think the tranny holds 14 quarts so you better use a big pail. I do do not know if the tranny will draw the fluid out of a clean pail. Might also be a good time to add a auxiliary cooler if you don't already have one.
Good luck!
Peter

 

[roscoFJ73]

I was thinking that maybe I could disconnect both lines at the rad and put one line into a pail of clean atf and the other line into a bucket for disposal. Does anyone see any flaws in this? Any input greatly appreciated as I'm trying to avoid a costly bill.

I think you would be better off draining as much as you can.Then fill her up and see its stays clean

 

[hotgemini]

The problem with what you're proposing is that the new fluid your adding is mixed in with the contaminated fluid back in the transmission during the process.

As rosco said, you're better off changing what you can get to. If you're really worried, change it, drive it for 10 minutes then change it again. Might as well do a new filter in the auto while you're there.

 

[GTSSportCoupe]

On my last wheeling trip i underestimated the depth of a hole and ended up being stuck in water over the headlights for about 15 mins. After getting out of the hole I noticed that the tranny wasn't shifting when it was supposed to. I checked the fluid and it was slightly pink and not translucent any more. Long story short, it's in my garage now and I'd like to do as close to a 100% fluid swap in the tranny as possible. Is this something that I can do at home or does it require special equipment to do properly? I was thinking that maybe I could disconnect both lines at the rad and put one line into a pail of clean atf and the other line into a bucket for disposal. Does anyone see any flaws in this? Any input greatly appreciated as I'm trying to avoid a costly bill.

P.S part of the long story involved needing to replace the alternator (seized) and starter (also seized).Trail was Fisher east

I'm pretty sure all auto trans fluid is red? Strange that yours was translucent to start with.

Is it possible the mechanical kick down cable got water in it and is binding a bit? This has the potential to really mess with the shifting.

If you think you've got water in it, or want to do a flush regardless, it is possible to do a full flush at home without bringing it to a shop.

As you guessed, you can use the pump in the transmission to pump out the old fluid. However, it does not 'suck' in new fluid from a bucket. It only pumps the old fluid out.

I've done this job many times and it is pretty straight forward. Here is how I do it:

- Buy 20l of new ATF. (DEX III or whatever your transmission calls for) This is stuff I've had really good luck with: http://www.walmart.ca/en/ip/maxlife-high-mileage-dexmerc-atf-multi-vehicle/6000078877210

- Make sure the engine is warm, and it does help to have a second person around for this job.

- Disconnect the 'outlet' hose (from the transmission) at the trans cooler and put it into a large bucket.

- Drain the trans fluid from the transmission pan, put the plug back in, and fill it back up with as much ATF (new) as you took out. Take note of how much this is.

- Have someone stand by the bucket to watch the fluid come out of the hose and make sure the hose stays in the bucket. Start the motor (shifter in park) and let the old fluid pump into the bucket. Only let it run for a few seconds, as you don't want it to pump the pan dry. Old fluid will be getting pumped out of the passages in the transmission as well as out of the torque converter. Only let half the amount you drained from the pan get pumped out. Shut the motor off.

- Top up the ATF level in the pan again with fresh ATF (add the same amount you pumped out)

- Start the engine again, and let it pump old fluid out again.

- Keep doing this until clean fluid comes out, about 15 litres in total. While doing this job, have your foot on the brake, and shift the trans through a different gear each time you start the motor. This will pump the old fluid out of the various areas of the transmission.

I'm sure others have written better procedures, but this is the general idea. If you are not sure which hose is the 'outlet' from the trans, just put both hoses in a bucket and you'll see the first time you start it which is which.

Don't just change the ATF in the pan, as that is less than 1/3 of whats in there! No point mixing fresh ATF with the old stuff.

This is a great procedure that has worked for me with every Auto trans vehicle I've ever owned. Saves money paying a shop to do it. And I know it's done right too.

 

[Joe70]

I'm pretty sure all auto trans fluid is red? Strange that yours was translucent to start with.

Is it possible the mechanical kick down cable got water in it and is binding a bit? This has the potential to really mess with the shifting.

If you think you've got water in it, or want to do a flush regardless, it is possible to do a full flush at home without bringing it to a shop.

As you guessed, you can use the pump in the transmission to pump out the old fluid. However, it does not 'suck' in new fluid from a bucket. It only pumps the old fluid out.

I've done this job many times and it is pretty straight forward. Here is how I do it:

- Buy 20l of new ATF. (DEX III or whatever your transmission calls for) This is stuff I've had really good luck with: http://www.walmart.ca/en/ip/maxlife-high-mileage-dexmerc-atf-multi-vehicle/6000078877210

- Make sure the engine is warm, and it does help to have a second person around for this job.

- Disconnect the 'outlet' hose (from the transmission) at the trans cooler and put it into a large bucket.

- Drain the trans fluid from the transmission pan, put the plug back in, and fill it back up with as much ATF (new) as you took out. Take note of how much this is.

- Have someone stand by the bucket to watch the fluid come out of the hose and make sure the hose stays in the bucket. Start the motor (shifter in park) and let the old fluid pump into the bucket. Only let it run for a few seconds, as you don't want it to pump the pan dry. Old fluid will be getting pumped out of the passages in the transmission as well as out of the torque converter. Only let half the amount you drained from the pan get pumped out. Shut the motor off.

- Top up the ATF level in the pan again with fresh ATF (add the same amount you pumped out)

- Start the engine again, and let it pump old fluid out again.

- Keep doing this until clean fluid comes out, about 15 litres in total. While doing this job, have your foot on the brake, and shift the trans through a different gear each time you start the motor. This will pump the old fluid out of the various areas of the transmission.

I'm sure others have written better procedures, but this is the general idea. If you are not sure which hose is the 'outlet' from the trans, just put both hoses in a bucket and you'll see the first time you start it which is which.

Don't just change the ATF in the pan, as that is less than 1/3 of whats in there! No point mixing fresh ATF with the old stuff.

This is a great procedure that has worked for me with every Auto trans vehicle I've ever owned. Saves money paying a shop to do it. And I know it's done right too.

Thank you very much. That is exactly what I was looking for. I will do this flush this weekend hopefully and I'll post the results. Right now the transmission will not shift out of first gear so I'm hoping that this will fix it, otherwise I'm not sure what I'll do next.

Thanks to all who responded.

 

[Henry Sun]

New owner of a 1990 LJ78 Prado. Just did a transmission flush following the super helpful instructions posted above by GTSSportCoupe. The previous owner didn't know what fluid was in the transmission, so it was necessary to replace all of it with new fluid. The A343F transmission uses D-II from the factory or Dexron III. I replaced it with Dex VI since it's backward compatible with Dex III and so far so good.
Some extra info about the flushing procedure:
-The outlet hose is the short one.
-The drain plug is M10 with a M10 crush washer.
-Jack up the front of the truck 10 degrees to fully drain the pan.
-It did take almost a full 20L of new ATF to do this.

The improvement in performance after the flush was very noticeable in my case!