Orange4boy's Rescue and Revival of a 2003 Prius

[bwilson4web]

Have you given any more thought about swap vs rebuild of transaxle?

SWAP WITH SALVAGE

• Potentially gets car 'on the road' soonest
• Risk of swapping in a trannie on last legs
• Leaves broken trannie for rebuild (known failed parts)

BLUEPRINT SALVAGE

• Puts replacement trannie at "0 miles" condition
• Leaves car immobile during rebuild (may lead to domestic issues)
• One trannie replacement

GET TWO AND REBUILD ONE

• Could be pricy, offset by reselling the first swap trannie
• Allows unpressured blueprint of final trannie
• Inspection of failed and the blueprint trannie gives insights to enhancements
• Need a winter project that can be done in a warm place

One of the differences between the NHW11 and NHW20 transaxle is the use of a bushing on one of the gears, NHW11, versus a bearing in the NHW20. Now there may not be enough casing metal to support a bearing replacement in the NHW11 but for sure, bushings wear. At a minimum, I would recommend measurement of the bushing but I would probably order the replacement and have a machine shop replace it anyway along with all of the seals.

Oil analysis has shown no molybdenum suggesting there may be a materials issue with moly greases that are often used in engine and transmission rebuilds. I would recommend using a non-moly based assembly grease, which may mean use of a petroleum-only grease. However, there is boron suggesting a hex-version of boron nitride impregnated grease might be an excellent option. For sure, I would work hard to make sure no moly is used without doing a through investigation ... especially around the magnets!

I have seen enough transaxle oil samples to suspect the area around the differential may accumulate 'debris.' I would recommend that before final assembly, adopt the cleanest standards possible and throughly clean every nook and cranny that might harbor any debris.

There is good data from the Dept. of Energy studies and my own that warming the transaxle to operating temperature improves performance. I have tried two, JC Whitney oil pan heaters and both have failed due to vibration between the power cord and the flat, resistance heater. Worse, half of the flat resistance heater is on the outside of the pan. My next version will be an immersion heater element built into the pan with a very secure, insulated, oil-tight, connector. This will reduce the electrical load and solve the vibration problem.

I am also intrigued by the use of a by-pass, micro-filter to get particles smaller than 10 micron out of the oil. But this is a very advanced technique and not cheap. Still, my early, hill roll down tests suggest this will significantly reduce rolling drag on cold startup.

BTW, would you elaborate on the 'pulsing drag' (I think you called it cogging) felt when pushing the car about?

Thanks,
Bob Wilson

[orange4boy]

From Wikipedia:

Cogging torque of electrical motors is the torque due to the interaction between the permanent magnets of the rotor and the stator slots of a Permanent Magnet (PM) machine. It is also known as detent or 'no-current' torque. Cogging torque is an undesirable component for the operation of such a motor. It is especially prominent at lower speeds, with the symptom of jerkiness.

Normally cogging is uniform in intensity but the cogging from the Prius transaxle was variable. It was very stiff then looser, then loose then stiff in a sort of random way. I would think this points to shorted coils interacting with the magnets. Why it would be "random" like that is confusing because presumably the magnets are uniform and would interact with the coils similarly. On second thought, if the number of coils vs magnets is different then a pattern might emerge where sometimes multiple shorted coils are interacting and sometimes just one. Make sense?

I'm not sure I'm up for a rebuild. Perhaps once I get a good replacement in there I could try it on the existing one.

I read on another forum of someone getting a tranny replaced for free by a dealer at 110K miles. I should give this a shot. It cant hurt.

I like the idea of a tranny block heater. I use one in my Previa engine year round and have been thinking of installing one in my tranny and diff. Good to know those pad heaters are unreliable. I won't get one of those. I know that you can get bolt on ones but have not looked into it. I think MetroMPG tested one of those here. Do you know of bolt through designs that would stand up to oil?

What is the simplest way to get a oil sample?

Darn TIS won't take canadian credit cards so I'm SOL for now on the shop manuals.

[wyatt]

Originally Posted by orange4boy

This is going to be honey's car so coroplast is strictly VERBOTEN! She tells me that Stainless steel is ok. She wants the salt flat disks and wheel skirts. My honey, she has a taste for the finer things...*sigh*

I will have to make the grill block a stealth unit because she like the Prius's "mouth". Working within these design constraints will be a challenge but I think I'm up to it.



I would never have chosen a white car before but I do love it now. Needs a good buffing and it will gleam!

If you don't plan on using the stainless moonies you can always try aluminum pizza pans. I don't know how the rims are on the earlier Prius, but I am sure that you can figure out how to attach them.

As far as coroplast goes, I understand the hesitation on using it on the exterior of the vehicle... it looks good until it gets warm in the sun and bends in places you didn't want it to... but you should be safe using it on the undertray like I did, or if you wanted to do a grill block from the inside of the grill, that should be safe also... Otherwise, I have seen you do some really good work with stainless, so maybe sticking to that would be cheaper and/or easier. You can check out my handiwork here, and see what I mean about the bending in the sun with my wiper block... you can see where the blocks of wood are. Underneath the car is pretty clean, and has been for almost 15,000 miles. The only reason I would update the design is to make it easier to remove for oil changes and other service.

[bwilson4web]

Originally Posted by orange4boy

. . .
What is the simplest way to get a oil sample?

Darn TIS won't take canadian credit cards so I'm SOL for now on the shop manuals.

For transaxle oil samples, I take a clean, DRY, water bottle, 0.5 L is perfect. After wiping down the area around the drain bolt, I loosen the drain bolt and let the first stream 'wash' the exterior. Then I put the bottle under and capture a sample (like giving a urine sample only from a transaxle.)

There are several labs and I suspect with all the mining activities in Canada, there are many choices. I've used R&D labs of Tampa FL and get a standard oil test along with a 40C and 100C oil viscosity test (also called out in getting an 'oil index'.) My tests run $20 (US) and I've been saving the results over in the Yahoo Group, "toyota-prius-sat2", an overflow group established to hold files when the other "Prius_Technical_Stuff" group folders exceeded the Yahoo quota.

On the maintenance manuals, send me a PM and 'we can do a deal.' Alternatively, you may be able to find used manuals on Ebay. Let me know which way you want to go.

I have a 'paypal' private company, 625k.inc@gmail.com, and I can buy the manuals and for my costs, ship them to you. In October 2005, I paid over $300 for my set and I don't know what they go for now. I bought my manuals from TIS and they came with a stack of inserts, update pages. So my first pass through the manuals was to put in the inserts. <grins>

I would recommend at a minimum, Vol. 2 and the electrical diagram. Volume 1 is your road map for understanding the codes. If you've ordered a scanner, you'll need volume 1 to understand what is going on and the fault tree.

Bob Wilson

[bwilson4web]

Since you are looking far afield in the rebuild, I would like to suggest a couple of other things to 'get out of the way:'

• spark plugs - they don't last forever
• air filter - toss the old, put in a new
• cabin air filter behind the glove compartment - they can pick up all sorts of funky stuff
• lubricate the hydrocarbon converter linkages - use a high temperature grease
• check belt - they almost last forever
• change radiator coolant - you'll get the inverter coolant anyway but radiator now is a good start
• consider 88C thermostat - I got some from Japan in January, at cost $20+shipping
• buff out haze over headlights - easy to do now
• measure all tread depth for all four tires - looking for abnormal wear pattern, can help on 4-wheel alignment
• 12V DC battery - they don't last forever and there are alternatives
• throttle plate cleaning - no so convienced about mass air flow cleaning but inspection is good
• PVC valve - what the heck, easy enough

[orange4boy]

Luckily, I have the service records.

New spark plugs 8,000km ago.
New 12V battery 8,000km ago.
brakes F 25% worn R 40% worn.
New inverter coolant pump @ 15,000km ago.
Headlights. look new.
New LF axle @ 107,000km
Throttle plate is a bit oily/gummy but not bad.
New computer @ 96,745km part# 89661-47054 was throwing codes: P3101, P3191, DP3199. They changed the engine oil at this service but not the transaxle fluid???

The others I will do later.

Added: I just looked up the recommended Transaxle fluid change interval:

Hybrid Transaxle
• Replace fluid every 72 months/96,000 km

Dealers! You have to watch them like a hawk. I wonder if This would get me some traction on a replacement from Toyota? Couldn't hurt to try.

[orange4boy]

Transaxle failure diagnosis:



Impact with hard object tore a slit in the transaxle pan. Slow leak...you know the rest.

I'm actually happy about this since I already knew the tranny was shot but I thought it was a reliability/manufacturing defect. This was just an accident. One less negative reliability statistic.

[bwilson4web]

I was hoping to see some interesting transaxle guts ... they are still interesting in a cadaver sort of way.

Bob Wilson

[orange4boy]

Found a few at Gundies Auto Recycling which have a 6 month warranty if installed by a certified tech. I have a friend who could sign off on it.

2002
Transmission
Toyota Prius 45,000--km--72,464 A B90519 $850.91
2002
Transmission
Toyota Prius AUTO (CVT) 77,000--km--123,994 A B90433 $752.91
2002
Transmission
Toyota Prius 1.5,AT 93,298--km--150,238 A PS69 $700

Will probably go for the lowest mileage one. Have to pick it up in Bellingham.

Found one locally for $900 but with unknown mileage. This one comes with a 4 month warranty. With exchange it's about the same as 850 US. I can look at this one on Wednesday and if it looks good I'll probably get it and save the border hassles.

[orange4boy]

Wreckers! I should know better. I got there today to find a 2007 engine and transaxle. He didn't know about the different generations. So I have to take the ferry back into town tomorrow because he is bringing one in. For sure a 2003 and this one apparently has 75000 K on it. He gave me a deal on the 03 for my trouble though. We'll see how it looks tomorrow.