In the USA they are using DW-1 in the older ones now. It's a better fluid and the Z1 is no longer sold here.

As for your choice. That's up to you. It's your money. Lots of people will tell you that the transmission as designed by Honda is different than all others. That is a true statement and as so you should use the Honda recommended fluid. Again, your money your call.

In my 17' RTL I am using Amsoil Synthetic in mine. Here's the link to what I'm using. Here's a link to my testing of that fluid long term via analysis. Again. Your call.

 

You say "One would think that Z1 oil is better for the engine than DW-1, so the one from Ravenol should be better for the transmission than anything else." I'm not sure what you are basing this on but as stevem already mentioned Honda replaced their Z1 with DW-1 fluid and it is now the recommended fluid for the Honda AT5 transmission in the GenI Ridgeline. The typical recommendation on this forum is to stick with Honda's own fluids rather the aftermarket fluids that are designed for MULTIPLE applications. The uniqueness of the Honda transmission design (automated manual transmission is one way to describe it) is main reason. It the case of the Ravenol products, they do appear to offer a specialized formula that is designed to specifically replace Honda's DW1 fluid. I have no idea how good their fluid is but the fact that it is, in theory, a specific design for Honda's transmission is a good thing in my mind and would make it worth considering if its readily available to you at a price considerably lower than Honda's DW1. If you think that the Ravenol DW1 is actually better than Honda's then I would be interested in knowing why you think that. In the case of the GenI Ridgeline there has been little if any indication that the transmission is problematic and many members here have well running high mileage vehicles using Honda's fluid in the transmission. Basically I'm not sure what you are trying to fix unless its a cost or availability thing.

 

When you change the timing bet also change the water pump and tensioner. Look at the serpentine belt and pulley as you will already be there with those parts.

 

Also, consider replacing the radiator as well. These can be a trouble area on early G1 Ridgelines. There are transmission cooling lines that ate plumbed through the radiator. Some of the fittings can fail, allowing the radiator fluid to contaminate the transmission fluid. If this happens, the transmission can suffer terminal damage.

 

Thank you, stevem5215, for your response. As you and the rest of the forum rightly indicate, I should use products designed by and for Honda. The reason I ask the question is because Ravenol has Z1 and DW-1 fluids, meaning they are specific and not for general use.

eurban, the reason I mentioned that one might think Z1 is better than DW-1 for the engine is because Z1 was originally designed to work in these engines, whereas DW-1 is its replacement. I thought perhaps DW-1 was intended for newer engines and that Z1 might be better, but as you correctly pointed out, DW-1 is recommended. So, thank you for your input; I will no longer consider Z1.

The reason I am so interested in Ravenol is because it is much easier to acquire here in Norway than the Honda fluid. It is also somewhat cheaper, but not by much. Another reason is that I have often read that Honda DW-1 is not fully synthetic, whereas Ravenol DW-1 is, and theoretically, it has all the necessary additives to replace DW-1.

Mark1, I forgot to mention, but yes, I ordered a complete kit that includes the timing belt, idler roller/pulley, tensioner roller/pulley, water pump and gasket, hydraulic tensioner, front camshaft seals, and serpentine drive belt.

ISO Truck, I had read about that, and I plan to change the radiator later. Between buying the car, a new screen, reverse camera, fluids, and parts, it is starting to become quite costly this month, haha. Do you think the radiator can last a few more months, or should I absolutely change it as soon as possible?

 

No telling how long the radiator can last. Some last forever without issues, others (like my privious 2008 ) wern't so lucky

At the very least inspect the fittings...

 

I hear you, @Sebaskurik . It’s no fun dumping money into a vehicle immediately after the expense of purchasing it.

You could probably wait a bit on the radiator. But there is a gamble.

If budget permits, I would recommend doing the radiator along with the other work.

The good news is a G1 Ridgeline is a very capable and versatile vehicle. Once you complete all this preventative maintenance, you will have a great truck!