Hello, So I bought my car (2008 IS250 75K miles) from CarMax last May and unfortunately it has been a terrible experience so far. The motor had considerable amounts of carbon buildup that showed their signs a couple months after I purchased the car. They replaced my bottom end with another used bottom end with less miles (58k) on it. Now my transmission seems to lag when going into the next gear. By that I mean the car will shift, the rpms will dip pretty low, and then after a small period of time the rpms will jump back up to where they should be and the car jerks a little. Also the shifts are not as smooth as they were before. Does anyone know if this seems like a normal occurance and am I overthinking or should I be concerned?

 

Let me guess, you are long overdue for transmission fluid change.

https://www.clublexus.com/forums/is-...ne-report.html

 

from what I've been told, the transmission is a sealed unit and you can only change about 1/4 of the fluid. Is that correct?

 

Sealed, yes; but still able to (via the dealership and special pumps) to remove and replace MOST of the OE fluid. If desired, you can also do a DIY "trickle flush" and refill.

 

Ok thank you for that information. I will try having the dealership do a fluids change and see if that helps.

 

Hey, super curious if that helped you’re Transmission, I’m not experiencing any of you’re problems, but would definitely like to have my tranny serviced.

 

So I had the transmission serviced a month ago and had my oil changed at the same time. The transmission definitely feels smoother. Im glad I did it and at the dealership it only cost about $375 for the trans service.

 

Thanks for you’re fast response, I didn’t expect you to reply for at least a week. Appreciate it..I was quoted the same, at the dealer, and I have like 100,000 miles more than you, so I hope everything goes smooth. Later.

 

The low rpm high gear selection is pretty normal for the 2ISX50. I'm not sure how steep of hill is steep, but they supposedly have a hill hold option built into ABS/Trac but I've never seen it work like I thought it should. Meaning if steep enough, it will roll at idle. Adding any throttle and my 350 holds it..

Look in the manual about hill hold... Maybe it's double tap brake pedal or something vs press and release on incline?

As for the actual low RPM shifts, it's sure fire way to carbon up a 250. In town I'd limit it to 3rd/4th so RPM's stay in the 1900 to 3200 RPM range. Whatever you save in gas over a year you'll pay 5X for to remove the carbon from the intake and valves.