How to replace rusted transmission cooler lines

I just replaced the transmission cooler lines on my 2006 Tacoma with towing package. Even though my truck is coated with fluid film or Woolwax before winter every year, battling rust in NE Ohio is a never ending battle. I replaced the front lines a few months ago and knew the rear lines would need to be replaced soon. I have been keeping an eye on them, but they went from a tiny trip to a large leak pretty quickly. If you live where they salt the roads, you might want to check yours.

I searched, but all the links to the FSM detailing this here are dead and I couldn't find anything detailing step by step so I thought I'd take a few pics along the way and detail how I did it:

1. Remove the engine under cover

2. Remove the rubber lines at the front of the vehicle


3. There are 2 clamps that hold the hard lines to the engine. If your lines are rusted, chances are the clamps are rusted and cannot be opened. Remove the entire clamp (12mm).




4. Disconnect the lines from the transmission. Most likely an open ended wrench will just destroy the fitting, so just cut the line off at the fitting and use a 6 point socket or closed ended wrench (17mm). I put a 19mm on the union to try to prevent it from turning and then used a very long wrench and was able to use my foot to push it. Laying under my truck, and lacking much upper body strength, I was able to apply steady pressure with my foot to break the lines loose. I read a few posts where a few people said they were unable to remove these, people recommended flare nut wrenches, but I saw no reason why I couldn't just cut the line so I would have less risk of rounding the fitting. As rusted as mine was, I have no doubt this wouldn't work for anyone else.


5. Remove the rusted bolts from the clamps. I used heat, PB blaster, and cleaned the threads with a wire brush, but they still broke off. I drilled and tapped them, but new ones are available if you prefer that route. Reinstall the clamps leaving them hanging open.


6. Install the upper (out) line on the top of the transmission first. If you do what I did and take the tags off both lines and have no clue which is which, the outlet line has a small white stripe of paint on it. I loosely attached it to the transmission, then made sure it lined up with both clamps. Then do the same with the lower line.


7. Attach the lines into the clamp. Make sure the rubber pads line up in the clamp. One of my lines did not have the pad in the correct spot on the line, so I pulled the rubber off of the old line and put it on the new one. Secure the lines in the clamps.

8. Finish tightening the lines at the transmission.

9. Put the rubber lines back on the front transmission lines.

10. Refill the transmission and run to temp to check for correct level (lots of threads on how to do this here in the forum)

I reminded myself why I use a piece of cardboard when I work under my truck instead of my dolly. No matter how well you think you have your long hair tied up, some will always manage to get rolled under a wheel, trapping you, lol. And I need to reapply Woolwax, but there was definitely still enough to cover my arms. I hope this helps anyone who needs to replace these, no reason to pay the dealer $900.

 

Great job.
This will surely helps some others out.

 

Thanks TnShooter. I've received so much great info here, just trying to give back a little! I hope this helps someone

 

Clear and concise information with excellent photos for this old guy in Vermont to replace these lines. Appreciate your efforts! Thanks.
(BTW I once owned a 1971 FJ40 in Tan)
Thanks Again Dianna

 

Hi Guys - I am planning to replace P/N 32907A ONLY tomorrow. Any ideas on the best ways to get the 32921J hoses off 32907A, without stressing out the rest of the plumbing.. some photos of the situation below..

 

Excellent post Dianna! It was very much appreciated especially since it had the best info I could find!

Last week I noted I had a trans cooler line leaking. So I picked both lines up at the nearest dealer right away.

Your tip about cutting the old line was brilliant! I cut mine so that I could carefully break them loose with a breaker bar. I just used a wire cutter and tried to do it as close to the fitting as possible. Worked like a charm. That fitting was the part I was the most worried about. I also didn't end up breaking either clamp so I was happy about that.

Everything went smoothly and when I was done I used my XTOOL D7 to check the trans temp before I drained the excess trans fluid.