Don't like the adverts?  Click here to remove them

A750 (auto) won’t select 5th gear

Slarps

New Member
Joined
Oct 31, 2015
Messages
3
Hey there. I have been searching everywhere and can’t find any information on the problem I’m having.
I have a 100 fte that I have owned for years that is always serviced and recently it has decided to select 5th gear irregularly and shifting hard sometimes. Once I thought I drove over something huge on the highway. It progressively got worse and I got a suggestion that the gas filter on the egr was blocked which I checked and it was so ordered a new one and before the replacement was fitted the trans stopped using 5th at all. I replaced the filter and since then every time it would normally go into 5th the engine light comes on instead.
I got the codes checked at it came back with 37 SLU solenoid sensor 68 centre diff system 2 and 74 speed/rotation sensor

all is stock apart from a 2” lift
 
Hey there. I have been searching everywhere and can’t find any information on the problem I’m having.
I have a 100 fte that I have owned for years that is always serviced and recently it has decided to select 5th gear irregularly and shifting hard sometimes. Once I thought I drove over something huge on the highway. It progressively got worse and I got a suggestion that the gas filter on the egr was blocked which I checked and it was so ordered a new one and before the replacement was fitted the trans stopped using 5th at all. I replaced the filter and since then every time it would normally go into 5th the engine light comes on instead.
I got the codes checked at it came back with 37 SLU solenoid sensor 68 centre diff system 2 and 74 speed/rotation sensor

all is stock apart from a 2” lift
Hi,

I'm not an auto box wizard, but there are some on LCC that are, so hopefully one of them will come to your aid.

Some more info would be great I.E year and mileage.

I have deducede Watson, that if you have the A750F box then it must be after 08-2003 and that if you have a 2" lift you've done away with the AHC.

Have you had any work done on the box? like fluid topped up or changed?

Good Luck.
 
Hi,

I'm not an auto box wizard, but there are some on LCC that are, so hopefully one of them will come to your aid.

Some more info would be great I.E year and mileage.

I have deducede Watson, that if you have the A750F box then it must be after 08-2003 and that if you have a 2" lift you've done away with the AHC.

Have you had any work done on the box? like fluid topped up or changed?

Good Luck.

it is 10/03 build with 360000km and it didn’t have ahc. It is a Sahara. I have had the fluid and filter changed because of the hard shifting and that made no change.
 
it is 10/03 build with 360000km and it didn’t have ahc. It is a Sahara. I have had the fluid and filter changed because of the hard shifting and that made no change.
Thanks for the info it will help if any other member looks at this, I know the problem existed before the fluid change, but was the new fluid 'WS' as the A750F box should only have WS fluid installed as opposed to the Dextron used in the previous 4 speed box.

There could also be probs with the solenoids or other inner workings due to wear over the years, Toyota said the new 5 speed WS fluid didn't need changing very often, only inspect under normal conditions, and replace at 80000K under severe conditions. here is part of the miantenance sechedule for you perusal. I personaly think 360000km is a lot for even WS auto fluid even though it's synthetic.
Hope this helps.

upload_2019-12-6_13-6-1.png

upload_2019-12-6_13-6-1.png
 
Last edited by a moderator:
This might be of some help aswell. :)

https://atracom.blob.core.windows.net/webinars/import/toyotaa750_a761_introduction.pdf

This bit's interesting.

The A750E/F uses two temperature sensors, each with a different function.•ATF Temp #1 –Used by the ECM to modify pressure control of the clutches and Brakes (if failed, 5thgear up-shift and Flex lock-up are prohibited)•ATF Temp #2 –Used by the ECM for shift timing control when the ATF temperature is high.
 
The trans guy I used know there stuff and I had it checked when I bought it at 270000km and he changed the filter and fluid at 360000km and said it didn’t need changing but couldn’t find any other issue with it.
I just drove 30km to town and it stayed in 4th the whole way. I drove back shortly after doing a the shopping and I had gone 28km it decided to go into 5th and 30 seconds later it did an almighty thump and changed back to 4th.
I am wondering if it has something to do with pressure regulator on the valve body
 
Don't like the adverts?  Click here to remove them
Back
Top