ibidu1

iTrader: (1)

Yes poor electricity in the vehicle can cause transmission problems. Have a shop or even auto parts store test the alternator and make sure the vehicle is getting proper voltage

arthy

This sounds very close to me problem, does it stall out when you try and park after a long/fast driving? I to have a GS300 06 model P2757, intermittent

irishger

I have experienced that a few times, I'm not sure if there is a connection between the slight jolt the engine gives after highway driving every now and again and the dodgy alternator. Thinking about it now, the last battery I had didn't last me long (2 years.) I wonder if bad diodes in the alternator caused it to drain

I'll let you know when I get the car back.

I've asked my mechanic to check all of the electrics on the car, ground strap, "repaired wires", fuses etc.

Fingers crossed that it was the alternator all along. Unlikely I know, but I'm an optimistic kind of fella.

arthy

I originally thought mine was to do with the MAF sensor, even after I cleaned it, it had no effect.
Very interested to see your findings, good luck!

irishger

Ok. I got the car back on Tuesday with a new alternator fitted and the transmission is the same as it was before the alternator went. The mechanic couldn't see any reason for it, he checked the usual wiring suspects ground points etc, he checked the trans fluid and its full too. He also checked for DTC's to no avail.


I've been driving all week and its been consistently bad until tonight during heavy rain again the car was as smooth as the day I bought it?


Thats two days in two weeks were we've had really heavy rain and both days my transmission has more or less changed gears smoothly without any rough gear changes and every day it hasn't rained really heavily its shifted gears like a tractor.


Since this problem started I've had codes P0172 + p0174 together, cleared them and then I got a p0171 + p0175, cleared them and then had the injectors cleaned, changed the MAF, Throttle Body, Alternator, Starter, Battery and still I have this very annoying problem.


Why would a car run better in heavy rain? is it electrics? or is it a vacuum leak? No codes popping up since the p2757. I'm stumped.

Gotcha350

You definitely have an electrical issue....i would have changed that damaged harness before I did any of that other work...these harnesses use such small gauge wire that a small nick or tear is enough to give problems. I would bite the bullet and change it because all you are doing is risking more damage.

irishger

I can't justify paying 1600 for a bunch of wires and then finding out that its something else all along.

Would a salvaged harness do the trick?

Gotcha350

As long as it's in good condition...you've already paid them to do some work that was not the problem...you think you have a problem but you haven't seen the carnage a shorted wiring harness can do...that is why I was saying to take it either to reputable shop or the dealer and tell them about the harness. From your own story none of these issues occurred before that person who worked on your car damaged the harness...now you are having intermittent issues....thats my .02 cents...that would have been the first thing I did...

I also mentioned that I would have changed the fluid since it's needed around this time anyway.

irishger

Yeah, I'm gonna get the fluid changed this week and try and get my paws on a salvaged harness too. I've been ringing around all week and nobody has one or at least an intact one.

Thanks for the input, Gotcha.

irishger

A quick update on my transmission problem. I left the car in for a fluid change today and the mechanic told me the starter guy had damaged more wires than he'd realised. He also told me my transmission is leaking from a seal at the back of the transmission leaving my trans with just one litre of fluid before he'd changed it, an expensive fix alone @600.

His recommendation was to recondition the transmission to restore it to its former glory at a cost of 1800.

That's to repair the transmission and the damaged wiring. Once repaired he doesn't see any reason with the right maintenance regime why I wouldn't get another 5/6 years from the transmission which I think is a good deal.

Thanks for your help guys, much appreciated.

Gotcha350

Glad you got to the bottom of it...I had a feeling that there was more damage hidden...

ibidu1

iTrader: (1)

Was this from the dealer? Because if your car only had 1 liter of fluid it wouldnt go anywhere. Plus I wouldnt trust a non lexus transmission shop to rebuild a lexus transmission. Many of these shops run non oem parts. Many rebuilt transmissions come back. A better solution if your transmission is truly toast I would slap in a used low mileage transmission.

I would have the wire repaired fully and wire loomed, then you can take the car to toyota and have them fill the transmission, and fix the leak. I would be weary about these transmission shops as they try to make a quick buck off of you with a transmission build.

irishger

No, it was from an independent shop who mainly specialises in Mercs and Bimmers but has worked on Lexus' with success or so he says. I left the car in to his place on Friday for a fluid change and by this stage the car was juddering on every gear really badly on and off. He called me later that day to tell me that he had bad news. He informed me that he'd drained about a litre of oil from the transmission and thats all that was left in there and then he told me that there was a slight leak in the transmission seal at the back of the box and that the car had been leaking ATF, slowly, for months probably.

He reckons the p2757 code was thrown because the torque converter was being starved of fluid and this had caused a lot of damage to the transmission. He refilled the transmission with ATF which initially helped it drive ok for a day or two although that could have been due to the ecu being reset as he was inspecting the wiring with the battery disconnected. Now it judders just as much as before the fluid change and the code popped up again on Saturday night.

Where I live, Toyota/Lexus generally don't repair transmissions, they only fit new parts. They usually sub the repair work out to reputable repair shops that may have technicians who will be certified by Toyota to work on their vehicles. When this happens you pay accordingly i.e. referred by Lexus to one of these shops you pay Lexus prices, referred by Toyota, Toyota prices etc. etc. This independent is not affiliated to Toyota/Lexus in any way but he is known as a very knowledgeable and competent guy (49 yrs working on transmissions) and has trained in Germany to work on German Transmissions.

Before I start investing in recon/second hand transmissions I'm gonna change that harness first.

MicahJr

I'm having the P2757 code come up. Can you tell me if yours has been solved?

irishger

Reconditioned the Torque Converter in mid December '14, Transmission worked ok-ish after the recon the transmission seems to be failing again. The transmission is starting to judder around the 40-50mph mark again.