transmission diagnosis How is it done?

[frangijon]

2 hours ago, Razor61 said:

Sé que existe o existía un escáner/lector de códigos portátil de Toyota. ¿Quizás el taller de Toyota/Lexus aún tenga uno que funcione y te permita usarlo?
Recuerdo haber visto uno de estos a la venta hace un tiempo. Buscaré más información sobre el escáner, el número de pieza, etc. y la publicaré aquí o te enviaré un mensaje.

Thanks

This is very good news for me, I hope for your help.

[frangijon]

56 minutes ago, Razor61 said:

Echa un vistazo al enlace que aparece a continuación, tal vez sea lo que necesitas. Parece más una herramienta de "monitoreo" que un lector de códigos, pero también puede leer códigos.
Por lo que puedo ver, es un módulo con Bluetooth, cables desnudos para conectar a un enchufe de diagnóstico, software TOYOBD1 en una tableta para leer los datos del automóvil.

OBD1READ con cables desnudos

Thanks

I will try to go today to the official Toyota workshop where the previous owner took the car, I will ask for the diagnosis if possible, I found this photograph, could it be the original Toyota machine, to scan the faults?

[frangijon]

45 minutes ago, BigBoomer said:

El dispositivo mencionado anteriormente puede funcionar (¡crucemos los dedos!).

El problema con los adaptadores que encontraste, Francisco, es que los lectores ODB2 modernos no saben cómo comunicarse con la versión específica de Toyota de ODB1, por lo que, si bien puede funcionar para algunos códigos, no funcionará para otros. Tampoco brindarán más información que las luces intermitentes en el tablero.

En cuanto a los problemas de transmisión, me parece que es un problema con el varillaje de la palanca de cambios o, lo más probable, que uno o más solenoides de la transmisión estén rotos.

Hello, the idea I have for the repair has several phases for me.

1-read fault codes

2-change transmission oil, because the one you have is not ATF due to color and smell, ATF is cherry red, this one is gold, I think the previous owner did Mercedes transmission oil

3-if it doesn't work, measure ohms and check solenoids,

4-If it doesn't work, then I will lower the gearbox and open it, inspect the clutches and rubber seals, which is where I think the fault is, it loses pressure due to the rubber packing and does not compress the clutches well, then they start to slip, burn out and the gearbox no longer moves, in the rear yes because the reverse clutch packs go in other packs, and if there is reverse gear the converter works and the oil pump too.

but I need to execute the correct steps

what do you think?

[Razor61]

30 minutes ago, frangijon said:

Thanks

I will try to go today to the official Toyota workshop where the previous owner took the car, I will ask for the diagnosis if possible, I found this photograph, could it be the original Toyota machine, to scan the faults?

I'm not sure it will connect and read the codes on OBD1.
I will be at the Lexus Dealer later to pickup my wife's IS250 after MOT and Service so will ask what is needed to read the transmission codes on a LS400 94-97.



Link to Lexus Intelligent Tester 2 information:

Toyota Intelligent Tester 2 Dealer level Diagnostics IT2 - Pro Auto Diagnostics

[Razor61]

26 minutes ago, frangijon said:

Hello, the idea I have for the repair has several phases for me.

1-read fault codes

2-change transmission oil, because the one you have is not ATF due to color and smell, ATF is cherry red, this one is gold, I think the previous owner did Mercedes transmission oil

3-if it doesn't work, measure ohms and check solenoids,

4-If it doesn't work, then I will lower the gearbox and open it, inspect the clutches and rubber seals, which is where I think the fault is, it loses pressure due to the rubber packing and does not compress the clutches well, then they start to slip, burn out and the gearbox no longer moves, in the rear yes because the reverse clutch packs go in other packs, and if there is reverse gear the converter works and the oil pump too.

but I need to execute the correct steps

what do you think?

2-change transmission oil, because the one you have is not ATF due to color and smell, ATF is cherry red, this one is gold, I think the previous owner did Mercedes transmission oil

I think you have figured out why the ATF is not cherry red as it should be for Toyota/Lexus, I watch the YouTube channel below, SPR Autos - Mercedes Specialist, when they drain the Transmission the fluid it is a golden colour so I think you are correct. I think Mercedes use mostly Gold coloured ATF but also use Red ATF, depending the model/transmission/year.
 

 

[Razor61]

Ok, so I discussed this situation with one of the mechanics at Lexus Bolton.
Good news maybe on the diagnostics side but bad news on the symptoms of the problem.

First, they still have the diagnostics equipment to connect to a 95 Lexus LS400 and read the engine/transmission codes so I would guess a Lexus dealership in Spain would maybe have the same.

I explained the symptoms, gearbox work/rebuild and the golden colour ATF (probably Mercedes ATF)
Solenoid issues are possible but not likely because there is no forward drive at all.
Opinion is the clutch pack/plates are the problem (maybe other parts as well, who knows) and using the wrong ATF has ‘destroyed’ the gearbox/clutch pack/plates. Transmission rebuild or replacement needed - this is the opinion of the Lexus mechanic.
Forward gears are driven through the clutches, reverse is driven by a gear assembly which fits with the symptoms of the clutch pack/plates being at fault.

[frangijon]

Thanks for your help, and sorry for all the trouble, the Lexus technician you spoke to is absolutely right, I think the problem is the clutches, I'm going to explain, as I said from the beginning, if there is reverse gear it is because there is pressure in the pump and the converter moves the oil, I think that the oil pressure began to leak through the seals that the clutch packs have, and where the solenoid valves are open so that the pressure passes and pushes those clutches and makes them firm, but if at that moment it begins to lose ATP pressure due to a seal, the clutches will not be tight, which makes them spin, slipping, the car moves forward, but the clutches slip. This burns out and in the end there is no movement, which is what I think is happening now.

This box has already been repaired by a specialist in the area, I was able to speak with him yesterday, and today he confirmed the repairs, the first one was in 2007, 186,000 km 115,575 milles

Again under warranty, the valve body was put in place in 20011 with 215,000 km 133,594 miles

This coming week, I will go to the garage to try to get him to come over with the diagnostic machine, where I have the car and do a diagnosis of the gearbox. I will also take the opportunity to ask him if the converter has been repaired, and also what the first repair of the gearbox included, so I will have a better idea of where this fault may be coming from and what decision I should make.

I was also thinking of opening a new post, with the title of Lexus 400 S project year 1995, so all the work, progress and problems I have can be seen by everyone, they will give their opinions, ask questions and together we will come up with something clearer and more fun. What do you think of this option?

Thanks

[Malc1]

I think that’s an excellent thought …….. others too ? 

NOW then, was your local gearbox specialist responsible for the possibly incorrect ATF oils ? 🤔

Malc 

[frangijon]

3 hours ago, Malc1 said:

Pienso que es una idea excelente… ¿otros también? 

AHORA entonces, ¿fue tu especialista local en cajas de cambios el responsable de los aceites ATF posiblemente incorrectos? 🤔

Malc 

Hello, I'll try to explain myself better, the car was bought in 1995 by César César, all the check-ups and maintenance were done at the official Toyota service in our city, when this car started to have gearbox failures, he took it to a specialist who repaired it, this specialist uses ATS F oil for these gearboxes that Lexus mounts, later on, he also changed the Mechatronics, and put new ATF in again, later the first owner César sold it and the second owner bought it, who shortly after, the gearbox started to slip, as his son explained to me, this second owner was a mechanic and his passion was Mercedes, so I deduce that the oil it uses now is Mercedes in gold color, a very fine transmission oil, as his son explained to me, who was the one who sold the car to me, every time I bought an automatic car with gearbox problems, I changed the oil and the filter and the Mercedes came back to life, with the Lexus it was not like that, I think he changed the oil. The gearbox kept slipping until it wore out or burned the clutches. This weekend I will take some oil out of the gearbox and upload some photos so you can see the color.

Thanks to everyone

[BigBoomer]

https://www.ebay.co.uk/itm/186738940740
Not sure how much the shipping to Spain would be but the gearbox is cheap enough.

[Spock66]

It's not the colour of the transmission oil that counts, its the specification, but if they are both conventional torque converter autos I would doubt there is a huge difference in the specification.

[ColinBarber]

1 minute ago, Spock66 said:

but if they are both conventional torque converter autos I would doubt there is a huge difference in the specification.

Many a Toyota/Lexus/Aisin transmission has been damaged by not using the correct T-IV or WS fluid. You can use non Toyota branded fluid if it conforms exactly to the Toyota spec but using anything else isn't advisable.