Type WS, 1.5k mi report

Hi folks,

I have started testing Type WS transaxle oil in my NHW11 03 Prius transaxle. The OEM oil is Type T-IV and I recently completed an Amsoil ATF test (NOT recommended due to excessive copper in the oil test.) I've installed a new transaxle pan with a JC Whitney heater and a drain plug with a small hole for drawing intermediate samples:


The first Type WS, 1.5k mi report, 278712, arrived. I had expected some cross contamination from the inaccessible areas but I was surprised by the amounts. Based upon viscosity, there was at least an 18% dilution. The wear and contamination material (aka., inaccessible sludge and additives,) suggest it is at least 25%:



This first test data suggests a transaxle flush is needed for our Prius. Since the NHW20 does not have a pan to drop, I will work on a system that uses the three major plugs: drain, side-fill, and top plug. It will recirculate the flush fluid to minimize wash fluid loss. Furthermore, it will use an NHW11 oil pickup screen and pipe with an in-pan, oil filter, to let us know when the flush has taken out all that can be easily removed.

I do think the external, transaxle oil filter modification makes sense and this is the only alternative for the NHW20s. However, I think an in-pan filter that fits around the oil pickup screen may be a simpler and quite adequate solution for our NHW11s.

Bob Wilson

 

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Aug 5 2007, 09:03 AM) [snapback]490845[/snapback]</div>

If your 2001 Prius has not had the transaxle oil changed and more than 30k miles, I would not recommend waiting. If you have it changed, make sure the following is done:

• drop and clean the pan - this is critical to reducing the contaminate loads
• sample for analysis - optional, this will give an idea of the status (~$20 for analysis)
• Type T-IV - unless you decide to join the Type WS experiment

If this is your first, expect to treat this as a flush. After we get more data, another change in 5-10,000 miles may make sense and be in your best long term interest.

Assuming you go forward with a preventative flush change, you have a choice between Type T-IV and Type WS. The Type T-IV is the OEM oil but the Type WS may turn out to be a good choice. Do not use Amsoil ATF since testing found high copper levels.

Bob Wilson

 

<div class='quotetop'>QUOTE(statultra @ Aug 5 2007, 06:26 PM) [snapback]491006[/snapback]</div>

Yes.

<div class='quotetop'>QUOTE(statultra @ Aug 5 2007, 06:26 PM) [snapback]491006[/snapback]</div>

Are you still driving that way?

Can you provide more details about what happened and the current operational state?

Thanks,
Bob Wilson

 

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Aug 5 2007, 10:00 PM) [snapback]491069[/snapback]</div>

Good deal. Do you know if they dropped the pan and cleaned it? There should have been a small charge for a gasket. No big deal if they didn't but it gives a clue.

I'm probably about six months away from another change. Based upon this first test, I want to work up a flush system first.

Bob Wilson

 

<div class='quotetop'>QUOTE(statultra @ Aug 6 2007, 10:48 AM) [snapback]491256[/snapback]</div>

Did you drop the pan and wipe out the gunk? I'm finding this is pretty important.

Bob Wilson