I have a 2014 GX460 with just under 300,000 miles. The vehicle has been extremely reliable and has never had any major mechanical issues.

About six months ago, I started noticing a transmission-related rattle/shudder. I never had it formally diagnosed, but my best guess at the time was torque converter shudder. I followed some advice to shift into S mode whenever it happens, and that has allowed me to keep driving it without major issues.

I recently drove it from Arkansas to Washington State, about 33 hours total, and only experienced a few minor mishaps. No burnt smell, no major slipping, and the vehicle still drives well overall.

Before leaving Arkansas, I tried to get a transmission flush at two different places in Texarkana, TX — Valvoline and Jiffy Lube — but both refused to do it, most likely because of the mileage and risk involved.

I’m now in Everett, WA and found what seems to be a good mechanic, but I’m trying to figure out how critical this issue really is and what the most reasonable course of action would be.

Should I pursue a full diagnosis right away, consider a drain-and-fill instead of a flush, look into the torque converter, or just monitor it since it has been manageable for a while?

Any advice from GX460 owners or mechanics would be appreciated.

 

... my take ... 300,000 miles ... if the transmission is very close to or at the point of needing a rebuild, doing several dump-refills first would maybe buy some time or possibly push the borderline situation over the edge ... to what may be a foregone conclusion anyway ... at least then you would know. I would not drop the $$ on a complete flush since the money may be "flushed" anyway, and considering the hassle of actually finding a shop that can properly perform ... and at a reasonable cost. If doing anything with the fluid, do not introduce another variable by using a non-Toyota brand. From what you described, I would stress over being stranded in the middle of nowhere ... towing cost ... and limited repair service options.

 

I think either drain and fill.... or "flush" is good option. But "flush" with the Volvo Gibbons method of disconnecting ATF line at transmission thermostat or radiator and cycling fluid through 2 quarts at a time with transmission's own pump by starting vehicle for 45 + seconds. 15+- quarts and you have bright red fluid coming out. There is an argument that you want some old fluid in there because the particles in the old fluid are helping the clutches grab. I was dubious of that argument. So I went with full fluid exchange.

I had a fairly intermittent, but unmistakable shudder around 130,000 (usually on long inclines at 65-75 mph) and did Gibbons full fluid exchange as above and have had 30,000 of smooth operation

One note: I did not check fluid level before draining. I would definitely do that. I have one theory that transmission was under or overfilled when I bought the vehicle used, causing the shudder only under certain conditions, e.g frothing from overfill under heavy load, or starved for fluid on incline. Unfortunately I'll never know.

Good luck! I want to get to 300,000 miles too!

 

If you have to go down road of OEM refurb replacement

https://parts.belllexusnorthscottsda...-35B70-84.html

 

Thanks for the great feedback. Money is not an issue right now but I am very frugal and I am hoping to get more miles out of this truck.

I am just driving now keeping in mind that the transmission may fail at any time and I have a plan in case that happens.

Appreciate the suggestion of buying a refurb transmission though. At the same time, I could take that 5K and put down on a 2020 or 2021, I will try to figure out what would be the best financial decision.

 

^ ... that would be my plan ... your GX is at the bottom of the depreciation curve but has some value ... as long as it's still rolling. Off-Roaders love the GX ... a 4-Runner on steroids that they would mod anyway so are less concerned by the mileage or any repair issues.

 

Have you picked up a new GX, or still tooling around on the older one? I salute you...it was incredibly balsy to take an 1800 mile trip.

Do you have a newer GX? If so, fill us in, please.