liquidz

This is the not about the plagued 2007/2008 ES350 with the tranmission issue. This is more of a generic issue. My car is a 2009 Lexus ES350 Premium line and was bought as a CPO from a Lexus dealership in Feb 2013. Currently mileage is ~98k KM

Issue: From a cold start and driving the car coming to a complete stop, I've noticed that the shifting from higher gear (2 or 3) down to the first gear at around 15-20 km/h is very abrupt. This is a little bit noticeable during the warm summer months and more pronounced during the winter cold months.

Changes: 1) Flushed transmission fluid last summer at Lexus dealership when the car was at ~78k KM, the issue is still present in the summer but a little less obvious.

What I know about the car is that:

1. Cold start of car, the engine's RPM runs higher until car switches from open to closed loop operation (or was it from close to open loop?) When engine runs at higher RPM, car would want to lunge forward a bit. This is normal and expected. Anyway to assist the engine warm-up faster? (Coolant change? Thermostat change?)
2. Once the car starts to warms-up (i.e. thermostat shows at about 1/4 of the entire gauge range). This is no longer an issue. When car is fully warmed-up the gauge is at about 1/2 marking as a reference point. So when car is starting to warm-up, is the transmission fluid warming up faster than the engine due to the shifting? Or is the fluid warming up due to the warmth from the engine bay?

Desired Final Results: We all know that Lexus are well known for a smooth and comfortable ride. And from a cold start, the shift characteristics isn't smooth. What can be done to solve this issue?

Lexi66

How many miles on your 09 ES350?

jcat_350

This is normal of just about any car. Especially being in Canada, your car is exposed to low temps that 'thicken' the fluids and until the car warms up, it'll shift odd like that. Every car I've ever owned outside of the stick shifts and one CVT has done it. It's a function of the operation of the transmission's valve body rods when the fluid is thick.

Lexus usually, though I don't know if the ES is the same way, has the transmission fluid run up through lines to underneath the radiator as a means of cooling the fluid. As you drive, your engine is trying to heat the coolant (engines are just big water heaters) but the air flow is cooling it off. This is why once you see the car warm up, it's no longer an issue.

liquidz

My car is currently at 98,000 KM and transmission flush was performed shortly after at I got the car at about 78k.

Thanks jcat_350, your answer just confirmed my thoughts that there's not much you can do. The transmission fluid used by Toyota/Lexus is already synthetic (right?) being the Toyota WS ATF?

jcat_350

I'll also caution to never have the machine powered flush done on a transmission. They cause more trouble than they fix.

Better to do a couple drain and fills than mess with that nonsense. Lexus says the system is sealed and thus the fluid should never need to be changed, but of course we know that that's BS. I would imagine that, yes, it is a synthetic fluid. I haven't dealt with it yet but will likely have the fluid changed this spring. My 07 is due for a big refresh (just hit 85k miles) in a couple months.