RX300 - Transmission issue

[sn0rg]

Hi everyone

 

I have just bought a 2002 RX300 with 103,000 miles.

 

I’ve had it a week and the car drives great but I occasionally get the following issue and am wondering if anyone can help diagnose it.

 

In crawling traffic, I can be going from around “creep” pace to maybe 7-10mph. Sometimes, as I’m gently accelerating, there’s a faint grinding sound which lasts no more than a second and during this moment it feels like the front wheels are pushing back against the rear wheel drive. The nose of the car will dip slightly before picking up again. Once above this low speed, the car is fine.

 

This doesn’t happen all the time, and it clearly needs sorting out. I’d like to know what it is likely to be, and if this is perhaps a common issue?

 

Many thanks in advance!

 

Thanks

Joe

 

 

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[PCM]

Who did you buy it from: dealer, private...?

Maybe ask them...?

[ColinBarber]

Not heard of this issue before, I wouldn't say it is common.

Maybe not related but I would recommend you drain/fill the transmission pan every couple of years to help keep the transmission fluid in good condition - the series I transmission, whilst not weak, can suffer issues. Only use Toyota T-IV fluid.

[BachelorDays]

I'd check fluid levels and condition (specially differentials). I'd also check front brake calipers.

You'd probably have a different set of symptoms if the transmission was slipping. The way you describe it is more like the front wheels needing an extra push to get going.

[Jaystar77]

Good call on the front brake calipers - well worth checking.  If the vehicle is making a grinding noise and it's holding back you could have a sticking one.

[welland]

On 2/9/2019 at 11:53 AM, sn0rg said:

It feels like the front wheels are pushing back against the rear wheel drive. 

That's interesting. Is the rx300 rear wheel drive, or all wheel drive?  

I had thought that the rx300 was like an rx400h, but without the electric motor motordrive to the rear wheels - ie only front wheel drive.  

[sn0rg]

Thanks for all the responses. My first thought was a sticky calliper too - but the push back/brake effect happens only after the car is moving. That might not rule it out though.
From what I read, the UK model is 50/50 split of 4WD, sending torque further back/front as required by traction.


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[m4rkw]

@sn0rg Next time you get the resistance, if safe to do so, try taking your foot off the pedal and pop it into neutral for a second to see if the resistance persists or goes away. If it goes away then it's in the driveline, if not then it's more likely something at the wheels, brakes etc.

[m4rkw]

Wheel bearings can make a grinding kind of sound when they're on the way out but I'm not sure that would explain the resistance.

[m4rkw]

@sn0rg actually, maybe don’t try that test. i think shifting while the car is moving might not be good for an autobox. maybe someone else knows for sure..

[m4rkw]

might be that shifting it to neutral is ok, but back into drive while it’s movinh might not be good. i don’t know for sure either way though.

[m4rkw]

@sn0rg according to this: https://www.popularmechanics.com/cars/how-to/a7890/if-you-shift-an-automatic-while-driving-will-you-damage-your-engine-11413677/

shifting into neutral while moving isn't dangerous to the transmission. it doesn't say anything about going back into drive however. depending on what speed you experience the problem at, you could perhaps find a road where you could reproduce the issue, select neutral to test whether it goes away and then brake to a stop before putting it back into drive.

obviously be careful and do this at your own risk, i'm not responsible for any problems caused :D

[m4rkw]

@sn0rg a trusted mechanic said this to me in relation to the idea of putting it into neutral and back into drive as a test:

"As a general driving procedure that could be a problem.  As an occasional test method there would be no problem."

 

Still - do at your own risk!

[sn0rg]

Thanks for the tips, but it happens so fast I wouldn’t be able to react fast enough to drop it out of gear. Leaning toward sticky calliper currently.


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[m4rkw]

The giveaway for a sticky calliper is usually lots of brake dust on one side only.