Delo 400 in euro 5 speed tranny
 

I have been using factory recommended ATF in my euro 5 speed ZF, now that summers have lengthned here thanks to global warming and its really sweltering hot this year, I found my tranny was heating up quite much compared to past and the shifting was no longer smooth specially after few hard runs in 40C weather, going against the norm, decided to put Delo 400 15W-40 in the tranny even though its comparatively thicker than standard ATF, the wonderful part is that even though I expected my shifting to become balkier due to heavier oil, it was a contradiction, the shifting has become noticeably smooth, reverse gear used to be an effort, quite recalcitrant needing double clutch or first and then reverse, now it falls at a flick of fingers, same goes for other gears as well, second used to be bit hard but now its smooth as butter, 3rd and 4th like churning butter, even upshifts are incredibly smoother with no notchiness at all. I am going to give it few more thousand miles to come to the final verdict but so far, so good. MY floorboard tells me that tranny is running far cooler than before where on hot days, I could feel the heat coming from there.

the synchros work from the viscosity of the oil. so if it is shifting too notchey i have also gone to thicker oil and had good success. i went to rotella in one of my high mileage 240s. smoothed that second gear crunch right out.

tom w

My tranny was only balky at high temps with ATF, at normal temps it would be OK but not great, now its positively great, the reverse gear engagement is heavenly, this is a much better way to get a smoother gearbox, also had the slave clutch cylinder cleaned out and a new kit put in, was on the original since 1999.

Just bought a new factory reman Ford ZF42CR 5 speed trans for a 97 Ford F250 diesel. The mfg told me not to use any trans lubricants other than Delo 15-40 or the 2 year warranty would be voided.

This is from a rebuilder that has been in business since 1926 and rebuilds only manual transmission.

Good enough for me!