I changed the trans fluid in my wife's 98 Expedition and by mistake used Mercon and should have used Mercon V. Does anyone know what problems this might cause, if any?

Thanks,
Chuck

 

What trans is in the truck?
If a 4r70w then Mercon V is the fluid, not straight Mercon.

 

I believe the correct fluid will be on the dip stick.

If Mercon V is correct, I think I'd have it flushed & refilled with Mercon V.

Tranny repairs are too expensive to take a chance.

 

Just drain and refill it with the proper stuff. The old Mercon isn't as slippery as the new stuff and can cause problems in the long run. You want the fluid providing the needed slippage, not the clutch plates. That would be bad.
Make sure you drain the torque converter too.

Darrin

 

If you have the 4R70w (trans code U on the door jam sticker), use Mercon V

If you have the 4R100 (trans code E) use Mercon.

Don't look at the dipstick as ford changed the 4R70w's fluid requirement in 98.

The difference is Mercon V has a friction modifier that the 4R70w needs and will kill a 4R100. The 4R100/E4OD are the two ford trannys designed NOT to have any friction modifier.

Look on your door jam sticker and see which tranny you have.

Adrianspeeder

 

My wife's Expedition is at the local Ford dealer this morning for a flush and fill of the transmission fluid ($120). Hopefully it wasn't damaged from using the incorrect fluid. I'll let you know if I can tell a difference in the performance of the transmission after the the flush and fill with Mercon V. Thanks for the reccomendations and replys.

Chuck

 

The transmission is a 4R70W, forgot to mention that before.

Chuck

 

From 94-97 Mercon was used in the 4R70w. Guess in 98 Ford finally figured out why some 4R70w's were burnin up and switched the recommended fluid to Mercon V which has the friction modifier. You should be fine though.

Adrianspeeder

 

Picked up Expedition from local Ford dealer, $138.63 for the flush and I had to clean up fluid spilled on fan shroud and around cooler fittings. I will let the dealer know that I had to clean the spilled fluid. No significant differences in performance that I can detect. I guess the effect would be long term. Thanks again.

Chuck