Builds "Rednexus" - 2007 GX470 Build and Fabrication Thread (5 Viewers)

[stupidchicken03]

how does the Hayden work with the CSF? Or are you not using the trans portion on the CSF?
Curious how the Hayden will help keep the trans from not heating up enough?

 

[Rednexus]

how does the Hayden work with the CSF? Or are you not using the trans portion on the CSF?
Curious how the Hayden will help keep the trans from not heating up enough?

The setup works in the same way the OEM cooler setup does, with the trans fluid going into the radiator and then into the aux cooler before going back to the transmission. The only difference is that the radiator and the trans cooler should each have more cooling capacity, and the Hayden 679 has a low-temp bypass where fluid only goes through the top row of the cooler during cold temperatures (my rig would over-cool in the winter with the 678 - trans temps of like 120F - which are too low).

With my old setup (OEM radiator and a Hayden 678), my trans got hot-ish (around 225F) on some extended 4Lo climbs out in CO, and my engine got to around 205F. It was only ~50-60F outside during these climbs. If I had been in the desert with the AC on, I think the engine and trans might have gotten quite hot. I'm hoping this setup will work a bit better for slow-speed crawling like that.

 

[stupidchicken03]

Ok that makes total sense. Had I thought about it for 2 seconds, im sure I could have gotten there lol - already been a loooong week at work.

Wild the temps got that warm when it was cool out!

 

[Rednexus]

Ok that makes total sense. Had I thought about it for 2 seconds, im sure I could have gotten there lol - already been a loooong week at work.

Wild the temps got that warm when it was cool out!

I drove it some this winter when it was around -5F and the trans shifted quite harshly! Probably not good on the transmission, and probably part of the reason the OEM coolers on these are under-sized (Toyota probably designed them to focused on cold-weather shifting and MPG as opposed to keeping things cool on mountain climbs).

If anyone wants my old 678 it's free for the cost of shipping and a few dollars to package it.

 

[zzyzx85]

If anyone wants my old 678 it's free for the cost of shipping and a few dollars to package it.

If only I hadn't already ordered one and don't want to deal with the hassle of returning it...

 

[Super]

If anyone wants my old 678 it's free for the cost of shipping and a few dollars to package it.

I’ll take that deal. Have a 698 already for the GX, but it can go on my Tundra.

 

[Rednexus]

So I've put 200 miles on the gears so far and have some more feedback:

- The rig rips. It revs quicker and puts you back in the seat harder. Overall the 2UZ feels much happier. It certainly had plenty of power before, but now it just feels even better .
- It's definitely more buzzy on the highway. 75 mph is about 2,550 rpm. I think it was maybe 2,200 rpm or so with 3.73s. As a result, it rarely downshifts pulling hills (and our highways around here have lots of steep hills). Fuel economy doesn't seem to have taken a huge hit, but I'll need more data to confirm. I'm confident it will tow drastically better.
- The ECGS break-in recommendations are very, very conservative. I think it's a CYA in case they set one up too tight and it runs hot. I'm checking my diffs with a heat gun - normally the rear is 165-175F and the front is 140-150F. Today the rear got up to 183F after about 20 miles going 70-75 mph on the highway. My understanding is that these are "normal" temps for a rear axle. It's speculative, but my gears probably would have been just fine with almost no break-in period. But, I'll honor their break-in recommendations so they honor their warranty.