I have a 1999 f-150 4.2 5 speed. Before i change the tranny oil, i just want to confirm i need to use Mercon and not Mercon V for the manual transmission. Thanks. for a hot day!

 

Mercon is just fine.

Adrianspeeder

 

No, Mercon V is only for automatic transmission. Manual transmission uses heavier oil. Check your owners manual for the oil you need to use on a manual transmission.

 

My '88 F150 5 speed also called for Mercon fluid. I had the same reaction as Davisote untill I read the manual and asked yet another dealer. Mercon is correct and it works quite well. I had 198K miles on it when I traded it and never had any gearbox problems (just clutches, but that's a different topic).

 

Dad and I have had 6 M5ODs and all have been happy and healthy on Mercon. Transfer cases too.

If you check the owners manual, it says mercon

Adrianspeeder

 

I also have the same truck as you with the manual transmission. I am a synthenic oil person. So,I changed my tranny oil to Mercon 5 which is a dino and synthenic blend. I noticed smoother shifts right away. So I thought what would full synthenic ATF do. After 500 miles,I drain it again and changed to full syn. ATF. But I had no changes with the transmission,accept a warm fuzzy feeling that my truck was all synthenic oil and ATF.
Steve

 

I use Vavoline Max Life ATF. It actually helped to reduce the famous "3rd gear grind". And my tranny is still working fine @ 54,760 miles. It's about time to change it again.

 

gm's syncromesh (sp) is a great fluid.