chiph9

The transmission programming will indeed downshift as you brake. It should not go into neutral & freewheel.
Grinding when going into P should also not happen. There is a shift control cable, and it may be out of adjustment.
I would find a better mechanic and pay the diagnosis fee.

Chip H.

jft

Thank you for the reply. Does the cable go into the transfer case? (which was replaced )

Lexus4321

GX's start to need lots of maintenance at about 10yrs old. The two main issues I have had were alternator (two died from what appears to be excessive heat from being too close to the exhaust header pipes, of which on my 3rd alternator I installed a cooling fan on the back of the alternator and it runs for approx 7min after vehicle is turned off), and the front rotors (Lexus sized them wrong, took me years to find the right combo of pads/rotors that work well w/o warping fast). And, all that crud under the intake is just a pita to deal with, very bad design in that area. There's boat load of space behind the engine filter box near firewall to place an emissions air pump! And starter under the intake just errgs me to no end.

chiph9

No, the transfer case is controlled two ways - mechanically via the H-N-L shift lever to choose a range, and electrically via the button on the console to lock the differential (there are additional wires to report to the ECU what range was selected, and whether the diff lock motor actually engaged)

The shift cable for the transmission goes to the transmission to select PRNDL

Chip H.

efaroh

I feel like I have this issue as well. Somewhere between 1500 to 1900 rpms with light throttle tip in, I can feel the slightest vibration on the steering wheel. I'm not sure where it's coming from. Could be engine or alignment. I just recently greased my driveshafts and it helps with transitions, but the slight vibration is still there on the steering wheel.

kiwiboy

Hi team
I've got an 03 gx470. Must be first model as the 03. the auto has a trans oil dipstick which I understand most dont.
Done a lot of work and put a lot of money into this car and now the trans has gone so I'm wonder if I should part with it.
The trans was slow to get moving in the morning in reverse and sometime would go into 4th gear but worked ok
I've just done the trans oil flush and test drive went great. It wasn't bad looking a little brown, I did the filter later year.
This morning it was horrible. No power and slow to rev up and would go over 3000rpm. I gave it 5mins to warm up.
Once I drove to 15mins to the trans shop and shut down it was fine again.
They said its slipping and needs rebuild at cost of $3500.
I doesn't feel like slipping to me i've had a trans go on me before and its not over revving actually the opposite under revving, it more like the oil isn't moving and lossing power.
I've check the fluid level hot and cold and its right.
The guy at the shop said the transmission has a computer that adapts to the fluid, maybe this need time to adjust when its cold.
He said I need the dealer special fluid blend, I showed him the castrol high mileage I put in that is listed as compatible for toyota.
Is this the wrong fluid? to tick when its cold maybe.
It has a small leak for a year now not sure where from. could the center diff cause this type off issues, should I check the oil level of this?

and have an offer of 6000 cash as is. Surely this would be the last issues for a while but you never know with older vehicles.
Looking the the price of 2012 tundas it crazy, cant see myself in gx460 to nice for my work.
Just spend $900 on new steering rack last week, all pumps and belts done last year.

On another note i've been meaning to post about the error code p0402 catalyst efficiency fault I've had for 2 year,
Tried everything, O2 sensors, gas cap, replaced evap lines. was about to replace the cats.
I solved it by remove o2 sensors and spray a can of brake cleaner into both catayltic converters. ( I have one each side is that normal or another 03 difference)
Make sure not to do this into hot exhaust and leave to air out dry for an hour or 2 after as its flammable
Fault code still come up if I tow my 5000Lb boat. Which it tows very comfortably with air suspension as it self levels and has the oil cooler, but the trans still gets warm on drivers leg at 70Mph. Wondered if the air bags may pop but so far so good (hauled across and down florida) they were replaced with the compressor by the last owner (would probably sell it now if that hadn't been done)

kiwiboy

Sorry I mean to say it does not have the over flow plug in the transmission drain pan.
And the drain plug is recessed up about and inch which looks different to all the videos I've seen on the trans oil filter change.
When I told the guy at the transmission shop it was and 03 AWD the price when from 3000 to 3500 not sure what the difference is as all GX are AWD.

Wronglane

How many miles are on this GX? Sure sounds like the transmission from what you have said.I would get the opinion of another trans shop.You do not need special transmission fluid although I would stick with Toyota WS,or,better yet,Amsoil.

You said you did a transmission flush.Was it a flush or a drain and fill?

kiwiboy

160k miles.
did the full flush 4 gallons, pumped out the cooler and pour in 2qt at a time.
It hard to show a shop as its normally ok by the time i drive 15miles and the transmission is heated up.
Is there some soleniods or bypass type thermostat that could be sticking.
could the fluid be too thick when its cold, it feel like that effecting it.

chiph9

You're in Florida. It's not too cold.

Try putting the Toyota WS fluid in and see what happens, as a cheap first fix.
If not, price out a parts yard transmission, a rebuilt transmission, and getting it rebuilt by a shop that knows what they're doing with an Aisin-Warner A750F transmission.

https://en.wikipedia.org/wiki/Toyota...smission#A750F

It's normal for the transmission hump to get warm on the interstate. I have had it soften some M&Ms I had in the cupholder.

If your mechanic has an infrared thermometer "gun", go for a long drive and have them compare the temps of the transmission and the transfer case.

Chip H.

LexusOnly7

I have a 2007 GX470 with no reverse. Any idea what it could be ? Also any idea if 4runner transmissions are interchangeable with these?

LeX2K

If you need the main unit
https://www.lexuspartsdirect.ca/p/Le...1060A6084.html

This is a direct fit 2003-2009 GX470 no other models show compatibility. As for what it could be not a transmission expert, generally no reverse means the transmission is worn out often from lack of maintenance. How many kilometers?

LexusOnly7

It only has 107k miles. You are right about the part #, it shows specific to the GX470 but I wonder if they used these in other Toyotas.

LeX2K

Searching that number on various Toyota (not Lexus) parts sites shows no results. Surprising actually. This listing says 2005-2009 GX
https://www.ebay.com/itm/255012608391

Did reverse fail all at once or was it more gradual?

IanB2

I would expect a V8 4x4 4th gen 4Runner to use the same transmission. I can't think of anything else that used the 4.7 V8 and had full time AWD.