bluejay9i6

Hey Guys,

I've been an owner of my 2005 GX460 for 7 years with approximately 106K. Lately, I have been noticing an issue when I perform a quick stop or an emergency stop, the car would pause for a while when I tried to accelerate. It feels like its takes 5 to 10 seconds to catch the gear. And when it does catch the gear, it jerks (kinda feels like dropping the clutch into a gear on a stick shift). This issue only comes up when the brakes are applied late to make an immediate stop. I'm not quite sure how to tackle the problem. The car's not throwing any CEL code. I had the drive shaft replace 7 years ago under the TSB. There were a couple times where the transmission went into limp mode which felt like it could only accelerate up to 2nd gear. I had to turn the car off and on to reset the transmission back to normal. I thinking I should replace the transmission fluid. Since it's a sealed system, does lexus even offer that service? Any advice would be greatly appreicated.

chiph9

Your dealer will change the fluid if you ask. A drain + fill using the drain plug will get about 1/3 of it out. Removing the pan to change the internal filter will get nearly all of it out (but is about $600). You can also ask if they will do a fluid exchange using the pipe to the external cooler up by the radiator.

If they use the word "flush", ask them exactly what their process is. You want to avoid any process that would involve running the fluid backwards or under pressure.

Also ask them to describe what their refill procedure is like. The transmission used in the GX470 is very sensitive to fill levels, as the fluid expands quite a bit when it gets hot. There's like a 6-page process on how to do it correctly.

Chip H.

DiabloX22

I had what was called a "Trans Vac" this would hook up to the cooler lines and replace all the fluid, it had a pause feature to drop the pan and change the filter. A trans vac is kind of rolling the dice, it may work or may not solve your problem. Call around to some trans shops and research them. It is possible to get a little fluid out and tell if it is burnt or not but still can have internal issues. I would not drive it or as little as possible, the more damage you do the more money usually. Did you have it checked when it went into limp mode? Your issue could have been happening since then.

bluejay9i6

Thanks for the advice guys. Under normal driving conditions, the car drives smooth as butter. As I've been reading more into transmission issues, I've noticed that the fluid level is very important. Last year, my car was involved in a front end accident. I recall the body shop replacing a rubber line that went into the transmission cooler. I'm wondering if replacing that hose, affected the fluid level which subsequently started this problem. If I take it a place to perform a full drain and refill, will the shop be able to replace the fluid back to factory standards or will they replace the same of fluid that will drain out?

LoneHiker

Everything you describe is characteristic of low fluid level. 99% certain that's the problem.

Since you've been running with low fluid for some time, you should do a fluid change. It's your choice whether you want to do a partial change or a full change, but if I were you I would do a full change in your situation.

Partial fluid change info:
https://www.clublexus.com/forums/gx-...oil-on-gx.html

Complete fluid change info:
https://www.clublexus.com/forums/gx-...er-change.html