The Dougler

iTrader: (1)

just wait until he goes to the dealer and says his torque converter is messed.

loulinjai

No offense taken, just sharing an opinion. I give very little credibility to SA's and parts guys at stealerships. After years of vehicle ownership, I have only met one SA that actually knows what he's talking about.

I just read the bottle on the DW-1. It says "full synthetic" on the front cover. I understand these terms don't always reflect what's in the product. I remember years ago when M1 was a "true" synthetic coming from a group IV base stock, while other companies marketed "full synthetic" products using group III stocks, which made M1 switching to group III for cost reasons. (or I may be wrong). And recently, I noticed Pennzoil has a "Ultra Class synthetic" product....these terms are really confusing...

But for the majority of Honda/Acura AT owners that buy Honda fluids and/or get it serviced at the dealer: is DW-1 an improvement over Z1 in any measurable way?

I hate cars

I believe DW-1 is an improvement. It uses a better base oil for sure and there is some hint that it contains less FM than Z1. I'm interested in hearing your feedback once you try it.

loulinjai

Time for an update.

I changed the fluid yesterday morning. The old fluid came out a dark red-brown color as expected, and I put in 3L of DW1. I only did one drain and fill (I know, it's not what it says in the manual, but I change the fluid more frequently than the intervals recommended in the manual.) Therefore, I have 4L of old Z1 and 3L of DW1 in my 04 TSX with 171k km.

I drove today in a variety of speeds and revs, both in D and Sportshift modes. I have redlined only once on the new fluid. Overall, the difference in shift points, shift speeds and gear engagement between pure Z1 and today are quite unnoticeable, with the exception of a 2 to 1 shift in sportshift mode, where a dramatic improvement in shift smoothness was felt.

I also noticed a difference when driving the car cold. I began to head home with a totally cooled down engine and transmission today. It was only 2 degrees C outside. Usually when running on pure Z1 on cold days (below freezing), I would notice a small vibration in the brake pedal when stopped at a light when the fluid is cold. This vibration will disappear when the fluid warms up after a few km of driving. But tonight, I noticed the vibration I would usually experience on cold starts has improved on my first stoplight. It is still there...but a lot less noticeable.