transmission slipping 2007 SR5 Desiel Automoatic Transmission failure... Again!

[Trentsa]

So it all stated about 12 months ago after moving house. The Car did a fair amount of work during the move and did give out on the last day. The trans would not grab any gear, and needed to be trucked to the local menchanic. They gave me the bad news that the trans was dead and needed to be removed, sent off and rebuilt. $4000.00 later i got her back. less than  a week into it i had a engine fault light appear, turned out to be a Tourqe clutch valve assembly fault. spoke to the person (i call him Tony) who rebuilt the trans. Tony said that he had seen this fault before but hasn't been able to correctly identify the cause, he has tried a few things in the past some with success but not always, at a cost of $500 I was not prepared at this point to throw that sorta coin at a guess. Tony had said to bring the car in and he will clear the code. Due to my work location i was unable to get to the shop quickly. Then the light turned off. I assumed it was a stuck valve and was now working fine. Fast forward about 10 months and then the code showed it self again. I took it to the mechaninc that had originally removed the Trans as i no longer had contact with Tony. This mechanic gave me the details of Tony again and suggested that returning there would be the best thing, they did check the oil in the trans only to find it was due for replacement. It was decided to wait until Tony could look at it as it might be a waste of oil. I was able to take the car to Tony and he checked the codes and other things then suggested that the best thing was to replace the oil for now which he would retain when he worked out what was going on and a possible repair. " ill have to check with my contacts and then get back to you" I left my business card and awaited his call. Atleast two weeks later upon returning home from work i had a new light pop up, this time it was a "A/T oil Temp". As i was traveling through country South Australia i didnt really want to get stuck. I also tow a tradie trailer which weighs in around 1.6 Tonne. So i reluctantly pressed on but gingerly driving. Then the gears started to slip so i pulled over and waited for about 45min. Restarted the the car and no lights, I assumed that the trans had cooled enough to press on. This happened one more time before i made it home. While i was waiting for it to cool again i remembered that i was going to change the oil. So when made it home i did that, better late then never right? I only put about 4lts in but my plan was to use this as a flushing oil while i went to work the next day then drain the oil and change the filter and put a good oil in. Test drove, all seemed fine. So the next day i headed to work, 40km later temp light turns on then trans slips at which point i pull over. The car was then flat bed trucked to Tony. The prelim assement (sight unseen) is he thinks i've burnt out the the front seal and possilbly the clutches. Not sure yet on the actual problem or cost. I am concerned that i will end up haveing to pay for a fix that i dont think is my fault. I suppose i am asking for any advice and experiences that you have had? or any input really?

[campbeam]

The life of the automatic transmission fluid can be very much affected by higher temeratures. 

Do you have a decent sized ATF oil cooler fitted? Also consider using a quality full synthetic ATF

If not, in my crystal ball, I can see more transmission work and servicing being required unless of course you give up towing 1.6 tonnes.

ATF Life and Temperature Relationship.docx

AMSOIL Signature Series Synthetic Oil Results.pdf

Synthetic Transmission Fluid.doc

Edited August 15, 2017 by campbeam
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[Trentsa]

campbeam -  you raise a point, and yes i will be adding an extra cooler as the stock one isnt cutting it. Thing is i was not informed of the need to add one and figured that the data sheet of the vehicle states a 2.5 T towing rating.