Can I run straight mercon in the 4r70w?

MalcolmV8 · Post by **MalcolmV8** » Fri Aug 26, 2005 2:23 pm

I know ford calls for the 4r70w to use Mercon V which is a full synthetic. I was wondering for short term usage can I just put straight mercon in? The stuff is so cheap compare to mercon V and I plan on running 10 or 20 miles, draining & re-filling, drive another 10 or 20 miles, drain & fill etc. probably two or three times to get any dirt out. Then I'll pull the pan, put in a new filter and the good mercon V in.
Or is that a bad idea?

Thanks
Malcolm

cjcnomor4 · Post by **cjcnomor4** » Fri Aug 26, 2005 2:30 pm

i'd run the mercon v. i've heard(but not seen) that mercon will cause the clutch plates to dissolve. you can use mercon v in a trans that calls for mercon but not the other way. i dont think youll need to flush the trans. i ve put junkyard units in, and just changed the front pump seal and oring extension housing seal and put a new filter in it and theyve been ok. you should be able to reuse the pan gasket on that one if it isnt damaged

MalcolmV8 · Post by **MalcolmV8** » Fri Aug 26, 2005 2:38 pm

OK thanks. I've already pulled the pan and installed a drain plug. I put in a new filter and a new gasket. I think I may have already poured some mercon in the torque converter when I first got it. I'll try and drain as much of that as possible. I also picked up a replacement O ring looking gasket that goes between the transmission and t-case. I didn't get a new oil pump seal. I assume that's right where the torque converter slides into the tranny? Does it just pop out and a new one taps in? I'll see if I can pick one of those up on my way home this evening.

I'll use mercon V as you suggested although I still think I'll drain it at least once

and then a second time with a filter change. Probably over kill but my tranny is a 2000 with only 11K miles. Been sitting for a while.

plowboy34 · Post by **plowboy34** » Fri Aug 26, 2005 4:31 pm

AGAIN, I agree with cjcnomor4. I would not run straight mercon, and if your tranny only has 11,000 miles there is no way I would waist my money flushing it. Automatics are very well sealed and it is hard for anything to get in them. If you have already put in new filter I would put in good oil and ship it. I believe you will be throwing away good money for no gain what so ever.

plowboy · Post by **plowboy** » Fri Aug 26, 2005 5:56 pm

if you want to flush it a little bit just put the suction side of your trans cooler line in a jug of clean mercon v and let it purge out the return line that way you will only waste a quart or two and it will clean out your cooler lines in the process