Transaxle replacement thread: Orange4boy's 2003 Prius

Just about to start the replacement of the toast transaxle on my 2003. I bought it like this for a song and now I have to do the dance. It was run dry from a slow leak and I have found a low mileage replacement in Edmonton which should arrive Monday or Tuesday.

Car has about 104k miles / 168000 km and is in very good shape otherwise.

The search for the transaxle is documented in: http://priuschat.com/forums/generation-1-prius-discussion/71157-how-choose-good-used-transaxle-ideas.html

Pics to come...

 

Picked up the replacement transaxle from my friend's studio and it seems as advertised. The oil is bright red and clean and thick. There isn't a spot of a leak anywhere. The cables are quite clean with just a bit of dust on them. All the bolts have the original paint marks on them and have never been removed. There is some dirt on the top and it's a bit corroded, but it presumably has been sitting on a shelf at the wreckers for a few years. The input shaft spins smoothly.

The only damage I could find was a cracked plastic connector and a few scratches on the inner surface of the output shaft bearing. Not a critical area. I can hopefully swap the cracked connector with one from the original unit.

I have to get it into the shop now to clean it up, drain the rest of the oil, clean the pan, fill it with new oil, replace the shaft seals? (they seem almost new), and inspect it as best I can.

Overall pic with a blot of the oil:



output shaft bearing inner surface scratches:



Another shot of the oil and the good condition of the shaft seal:

 

Major progress today. After working on it all day, the transaxle is ready to drop. Too beat to post pics. Will have to wait till tomorrow.

The trickiest bits so far were the harness connectors to the power steering motor. (They are buried behind and below the brake distribution box) and the motor leads to MG1 which I had to unbolt from the transaxle because the last dimwit mechanic to work on it tightened the torx bolts on the inverter so tight, I bent/twisted the torx bit trying to remove it. Will have to try heat tomorrow.

 

Tomfreed,

Glad to see you are watching. You are the Gen1 master now. You pictures helped a lot, thanks.

I have a question. How do you remove the axles from the transaxle? There is nothing in my manual for that.

Yes these buggers are heavy. 300lbs at least. It's all that copper. I have an ATV lift which should work to lift the transaxle out and in. The lift height is not quite enough but I should be able to rig up something to make it work.

Today I drop it.

 

Pics. In no particular order.

 

Do you have to remove the c-clip? Or does it slide through that spiral slot in the bearing race?

 

Got the beast out. That is a tight fit.

Tomfreed, do you gave any tips on getting it out more easily? The ICE motor had to be pried out of the way to make room. How I will get the new one in is a mystery. I may hoist it in from below with a chain hoist mounted above. The ability to swing and rock would be a big help in getting it in.

Now that it's out I'm not getting the cogging. I can spin the CV joints which spins the input shaft. I think it means that the mg2 is ceased because the cogging was the ICE being rotated by the wheels. I imagine if it was not ceased it would rotate freely so the Ice would be unmoved by wheel rotation in neutral. . Just a guess. Would also explain the lurch when I tried to start the car. It would immediately stop and flash all the warning lights.

 

That sounds like a "fun" project. A bit beyond me at this point. It is a powerful motor for an EV all on it's own. Has anyone figured the efficiency of MG1 and 2? I know that Agni Motors is getting up to 93% on their PMDC but that's apples to oranges. The MGs are 3phase AC right?

 

Got the replacement transaxle out of the van and hoisted up to take off and clean the sump. The newer sump is just dusted lightly with filings and the magnet is a little bump compared with the huge pile on the old one.

Compare and contrast:













Hopeful puppy is hopeful... Walkies? Walkies? Walkies? How about now? Now? ... Now?... Now?... Walkies now?.. Now? Walkies?

 

I have a question about the inverter coolant. What is the correct mix for the inverter? I have read that water is a better heat sink than glycol which is why you want a higher water to glycol ratio.

Bottle gives the following info: 65% -56C 134C boiling point / 50% -37C 109C boiling point. I doubt boiling point is an issue and It very rarely gets blow -15C here.

 

Mounted my chain hoist to the joists of the carport yesterday and made a bracket for the tranny. Works great. Did all the work at chest level.

Done:

1) Drilled out one MG1 cable attachment cover bolt as it was seized by the overzealous use of an impact drill. I had to remove the wires from the transaxle still in the car during teardown because of this.

2) Installed MG1 cables in Transaxle and sealed cover with RTV.

3) Cleaned and replaced oil pan. The sediment was very fine and black. It seemed to be coarser towards the magnet suggesting a good wear in pattern. There was just a sprinkling of bronze glitter.

4) Cleaned out CV joints. Will re-pack tomorrow with synthetic grease. Stock grease is thin and flows fairly easily.

5) Swapped brackets and other pits and pieces to new trans.

To do:

1) Install new axle seals. They are waiting at the dealer for me to pick up. Probably will have to wait till Tuesday to do it. I might install the Tranny now and the seals later.

2) Check and grease cat. valve linkage.

3) Fill tranny with WS.