Builds Homer's 2003 GX470 Build 8.2 4.56 2.5 (3 Viewers)

[HomersCanyonero]

A 678 should be fine in your climate. It's what I'm running. However it can really over-cool in the winter. Driving my rig on below-freezing days, sometimes the temp maxes out at like 120F, which is just too low for fuel economy and probably not good on the transmission either. I fixed that by cutting up a sheet of 1/8" rubber that blocks about 2/3 of the cooler during the winter. Since I'm pulling the rig apart in a few weeks to replace the radiator, I'm going to switch to a 698 with the built-in thermal bypass. I doubt you get many below-freezing days, so you may not have the problem that I did.

My question is doesn’t the GX470 transmission already have a built-in thermal control valve?

It seems to me the built in thermal control valve does what the 698 does just a little differently. So, it’s seems a 698 would introduce a second bypass to the cooler.

That’s what my research says, but its theory at his point.

 

[Rednexus]

My question is doesn’t the GX470 transmission already have a built-in thermal control valve?

It seems to me the built in thermal control valve does what the 698 does just a little differently. So, it’s seems a 698 would introduce a second bypass to the cooler.

That’s what my research says, but its theory at his point.

The GX470 does not have built-in thermal control. The GX460, however, does have a thermostat on the transmission that opens at a set temp. This is evidenced by my trans running very cold in the winter.

 

[yeos]

A 678 should be fine in your climate. It's what I'm running. However it can really over-cool in the winter. Driving my rig on below-freezing days, sometimes the temp maxes out at like 120F, which is just too low for fuel economy and probably not good on the transmission either. I fixed that by cutting up a sheet of 1/8" rubber that blocks about 2/3 of the cooler during the winter. Since I'm pulling the rig apart in a few weeks to replace the radiator, I'm going to switch to a 698 with the built-in thermal bypass. I doubt you get many below-freezing days, so you may not have the problem that I did.

I have lived in Eastern WA for 5 years and experienced the low trans temps while running the Hayden 678. My commute to work is 10 miles, but the trans fluid had troubles getting above 100. I switched over to the Hayden 698 this past December. Though we had a very mild winter I did notice a slight improvement in the trans temps. I had no troubles getting it at or above 120 degrees.

 

[HomersCanyonero]

The GX470 does not have built-in thermal control. The GX460, however, does have a thermostat on the transmission that opens at a set temp. This is evidenced by my trans running very cold in the winter.

I checked again with copilot and now it says the GX470 doesn’t have a thermal control valve! What a crock copilot is.

 

[HomersCanyonero]

I have lived in Eastern WA for 5 years and experienced the low trans temps while running the Hayden 678. My commute to work is 10 miles, but the trans fluid had troubles getting above 100. I switched over to the Hayden 698 this past December. Though we had a very mild winter I did notice a slight improvement in the trans temps. I had no troubles getting it at or above 120 degrees.

I’m gonna return the Hayden 678 and get the Hayden 698.

Good thing it’s still in the box!

 

[Rednexus]

I checked again with copilot and now it says the GX470 doesn’t have a thermal control valve! What a crock copilot is.

AI likes to give wrong answers . I've asked it questions for fun sometimes related to what I do for a living and it's given responses that might look OK to a non-expert, but were totally incorrect.

 

[HomersCanyonero]

@Rednexus thanks for the tip on the lack of a built in thermal control valve on the GX470.

I’m now trying to figure out how the Hayden 698 works and found this comment in the attached photos

So, the 698 has the same dimensions (11” by 9.5” by 0.75”) as the 678 and it should fit on my Goliath bracket.

The bypass on the Hayden 698 appears to work on pressure not temperature based on the comment I saw in the summit racing website.

Anyways, I’m waiting for both the Goliath bracket and the Hayden 698 (Rock Auto) to arrive.

 

[Rednexus]

I'll have my 698 installed in a few weeks and will update my build thread on if it has the same mounting hole positions as the 678 does.

 

[HomersCanyonero]

Got the master brake cylinder assembly replaced with a brand new one from Toyota

The old one was in good working order. I can hear the new one prime too when I press the key fob to unlock car!

Also replaced the gas pump and sending unit. However, this was a new aftermarket one not a new Toyota oem.

 

[HomersCanyonero]

Hayden 698 installed….this one is the same exact dimensions as the 678, but the difference is the 698 has an internal bypass valve

The most difficult part of the install is the bottom 3 bolts…what a pain in the ass when you have a winch installed on a hybrid bumper!

 

[HomersCanyonero]

Here’s a photo of the bottom 3 bolts. I skipped one and only installed the other two…big pain in the arse to get your hand in there and start those fricken little bolts when you have a winch and hybrid bumper on the way.

 

[Hardazclay]

Hayden 698 installed….this one is the same exact dimensions as the 678, but the difference is the 698 has an internal bypass valve

The most difficult part of the install is the bottom 3 bolts…what a pain in the ass when you have a winch installed on a hybrid bumper!

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Did you use the stock hoses or did you need more length to fit the 698? Other than the 698 did you need to purchase anything else?

 

[HomersCanyonero]

Did you use the stock hoses or did you need more length to fit the 698? Other than the 698 did you need to purchase anything else?

The Hayden transmission cooler comes with a brand new hose that you can cut to size.

However, I re-used my factory hoses and factory clamps since they reached perfectly.

The only extra part was the Goliath Offroad bracket with optional spacers to fit the factory horns without hitting the cooler.

I saved the new hose as a trail spare.

I did have to remove some factory brackets and bend one back to provide support for the ac hardline. I could have skipped this step but I wanted to restore some level of support since I had removed that bracket that holds the ac line.

See the photo of my MacGyver support bracket. I use a zip tie plus a pad from the Hayden kit.

That’s a factory oem bracket bent and reattached in a different spot to hold the hard ac line.

I didn’t add any extra ATF, but at the next transmission service…I’m gonna replace those hoses and clamps. I should have ordered oem tension clamps for the new hose, but I didn’t.