Thread: Trans over temp light

Early one morning last week I towed a trailer mounted 2.5 tonne silenced generator over a local 555 metre hill called the Rimutaka Hill (a favourite amongst motorcyclists) with my 300TDi auto. And the bloody transmission over temperature light kept coming on. I have already replaced the cooler with the biggest one I could find due to the original being blocked so was a bit miffed to have this happen. On the drive up I was hoping maybe the temp sensor is faulty or that the breathers are blocked and this caused the temperature to increase.
I left the generator over the hill for the week and commuted back and forth. During my drives I was pondering the answer to the problem.
Day three it came to me and I was a complete numbty. When towing over the Disco was in 1st gear and working hard. So why not just put into low ratio.
So on the way back with the generator I put it into low ratio at the bottom of the hill and the whole combination soared up running comfortably at 50km/h in top with the occassional foray into 3rd for tight corners. What a difference it made no light on the dash or the smell of hot transmission.

Adrian

Hi Adrian,
If the temp light has come on you might want to check the fluid as it may have overheated and burned. Mine did this a couple of time when towing a trailer and now its in the transmission shop getting rebuilt. I'm getting larger clutches etc put in from a 4HP24 box to strengthen the box and fully synthetic fluid. I'm still thinking i'll have to upgrade the cooler as well but will see how it goes. Did you put a second cooler or just put a bigger one in?
My 97 TDI only had 118,000k on the clock but the towing killed the transmission, the guy who is rebuilding it specialises in ZF and says they are only really built to cope with the car and not suited to towing.
Mine got so hot the kickdown cable melted and the plastic cowling around the cooler pipe also melted. I'm only towing a 1000kg trailer and also used to drop into low range on big hills so that TC lockup occurred earlier than the usual 80KMH+. This helped but the damage was already done once the light had come on a few times.
Cheers
Mark