Gearbox Shudders In Reverse

[muscleboy1957]

Seeking some assistance in identifying the cause of a shudder in our Lexus GS300 when we engage reverse gear. As we then move back the gearbox has an initial and quite noticable shudder but then goes away as the speed picks up a little going backwards.

The gearbox has also had the occasional 'moment' over the past few months when it has stuck in gear briefly etc but these other problems have been intermittent.

I read on another post on this forum about gearbox problems that were solved by replacing the Vehicle Speed Sensor (VSS) but there was NO mention of a shudder in reverse on these posts.

Any comments or suggestions would be appreciated.

I am worried that if I take it to a Lexus dealer they will say that I need a replacement gearbox which are $$$$$$$$ in Australia.

Thanks

MuscleBoy1957 - (Sydney, Australia)

[intakerGS]

Many issues may contribute to shudder or delayed (trans)action from AT. Besides 'shudder' in reverse, it seems to (intermittent) get stuck in other gear too, which may point to a common divider.

It would help to provide more details about things already checked and/or maintenance history, as it's impossible to provide any valid suggestion at this stage. For example: when was ATF refreshed/flushed, ATF level, ATF color, CEL warning, when did it start, milage of car, etc.

Any proper AT shop should be able to check this, or at least give you some hints.

[SRK]

First of all check fluid level. Probably you've done that - but be sure. Then consider that the shudder could be the driveshaft - a failed coupler or u-joint can vibrate when loaded in the opposite direction.

If that's ok then perhaps it is indeed the trans, and from the Lexus techs I know, very well a bad solenoid or accumulator. What's called a "bottom fix" in the auto trans industry, not a removal and rebuild.