trans fluid question

Reply Subscribe

Thread Tools

Search this Thread

Aug 4, 2008 | 06:07 PM

kmfdm

Thread Starter

New User

Joined: May 2008

Posts: 24

Likes: 0

trans fluid question

ok so i have a 98 4.0. it is doing alot of the valve body problems that i have read about on this and a few other sites...ie shift flare, minimal 1st gear braking, and some slippage feeling when power is applyed hard. now any other time i would jump to rebuild the VB and take care of the updates....but i found a quart of the trans fluid in the rear door cubby pocket that the previous owner put in it when he said he had just did a flush when i got it off him...it was some mercon 3. i have put about 2000 miles on it since i got it from him plus who knows how much he put on it. the fluid looks very clean and new, so i take it he didnt drive it much. plus the problems were slowly starting one on top of another...is it the fluid breaking down or what? thanks

Aug 4, 2008 | 06:35 PM

mfp4073

Fleet Mechanic

Joined: Sep 2007

Posts: 1,726

Likes: 10

From: down south

I am not an expert, but I keep seeing that fluid is very important to the merc V trannys. Only problem is that at $4 a qt it gets expensive to do a full replacement. How many miles on your truck? I did a full rebuild on my tranny and found a great price on a fully rebuilt and upgraded valve bodies from central valve bodies, that could be a last resort for about $350. You could always try the fluid replacement. At about $50 its a lot cheaper than most other fixes though.

and just to ask.....are you a drug against war?

Aug 5, 2008 | 09:01 AM

pawpaw

Moderator

Joined: Jan 2004

Posts: 13,851

Likes: 111

From: SW Va

There is no such thing as Mercon-3.
Did you mean Mercon/Dexron-3???? If so he likely used the wrong fluid in the tranny.

Check your owners manual for the proper fluid type, my 99 5R55E specifies Mercon-V & if thats what yours calls for, then try a full fluid pump out, to flush all the Mercon & see how it goes.

Aug 5, 2008 | 11:34 AM

B A dawg

Senior User

Joined: Jan 2004

Posts: 130

Likes: 0

From: People's Republic of CA

Ya, my 98 4.0 with the 55 takes Mercon V. (Mercon 5)
Check the dipstick, it says on the dipstick what kind of fluid to use.
I'll bet money it's the V tho.
Do what pawpaw says, a COMPLETE flush, put in the V, see if that helps. If it don't, your trans is possibly toast, sorry to say.
If it improves, I would run it for a little bit, then do another flush.
You wanna get ALL that Dex3/ Mercon outta there. Unfortunately, your TC doesn't have a drain plug, so flushing is your only option.
Maybe someone else can post on this topic who has had personal experience with the wrong fluid in the trans. If I recall, the V allows for smoother shifts, among other things, but I can't remember specifically what the performance differences are between the two. Fluid misapplication can cause slippage, harsh shifting, damage, etc. tho.

Last edited by B A dawg; Aug 5, 2008 at 11:44 AM. Reason: clarify

Aug 5, 2008 | 12:16 PM

kmfdm

Thread Starter

New User

Joined: May 2008

Posts: 24

Likes: 0

yea i was thinking of trying just the fluid first, and go from there. and it is all escalating slowly...so im not sure if its just the lower quality fluid breaking down or what? but yea i will flush it all out and try that first..thanks!

Aug 5, 2008 | 01:30 PM

pawpaw

Moderator

Joined: Jan 2004

Posts: 13,851

Likes: 111

From: SW Va

Here is how I do a complete tranny fluid pump out on my 5R55E tranny.

With the vehicle level & the tranny return line disconnected & plugged & a section of hose connected to the return side of the cooler, the oher end in a catch container, you can then start the engine, let it idle & the tranny pump will nearly empty the pan at a rate of one qt/15 seonds. Makes dropping the pan WAY less messy.

Here are more details on how I do it.
https://www.ford-trucks.com/forums/6...-pump-out.html

Maybe it'll prove helpful.
Let us know how it goes.