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
after having done the external filter mod and monitoring the UOA results, I can whole heartedly recommend not bothering to do it. Unless someone can come up with a 5 micron filter, I can say a 15 isn't worth the time or effort. Just change the oil on a regular basis and be done with it. Bin there done that.
im just wondering, is there fluid pressure in the hybrid transaxle? ( enough to pump it through a filter or something ) btw b4wilsonweb, i actually ran my 01 prius without type t-iv ( it was dry ) i guess it just had surface lubricants, but i drove the car in 90+ degree weather in NJ and no problems, would u think that being that i had no type t-iv that there would be more contaminants in the present type t-iv i filled?
<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(bwilson4web @ Aug 5 2007, 02:21 PM) [snapback]490924[/snapback]</div> Had it changed at 60k, today mileage is at 80k. Will see outcome of your testing to decide what and when.
<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(catgic @ Aug 6 2007, 06:40 AM) [snapback]491151[/snapback]</div> Shame on you. I try to make certain that the next person buying any car I have replaced is not stuck with avoidable problems. This requires that I maintain my car as if I were going to keep it forever, independent of my future purchase plans. Bob's research into proper Prii maintenance has helped many of us take better car of our Prii. Someday he will actually buy a Gen2 (if his classic ever wears out) and be able to help the majority of owners even more. JeffD
well the current operational state of the car is normal, when i drained out the residual fluid it uh smelled like wax or something. Other than that it runs real good ( 20k miles since i ran it without fluid for 50 miles )
<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
<div class='quotetop'>QUOTE(bwilson4web @ Aug 6 2007, 04:49 AM) [snapback]491142[/snapback]</div> No clue other than the simple statement of replacing transaxle fluid T-IV. But this is exactly why I'm here at PriusChat, to find out the right way to do it myself.....to make sure it is done right. Like including dropping the pan and looking at what might be in the bottom.
on that prius i didnt drop the pan, but when the residual oil drained it smelled horrible, that prius is now my sisters and ran a good 20k miles with no problems, next time ill drop the pan.... my other 01 is in desperate need of a fluid change and i will drop the pan and check for stuff.
