What transmission fluid to use for '98 3.8L?

The Haynes manual said something like Ford compatible fluids but I don't want to go to the dealer.

Will the "Mobile 1 Synthetic Transmission Oil Mercon V" work for my '98 3.8L?

Yes. Anything rated Mercon V should work.

The Haynes manual said something like Ford compatible fluids but I don't want to go to the dealer.

Will the "Mobile 1 Synthetic Transmission Oil Mercon V" work for my '98 3.8L?

I believe that 98 was the change year (form Mercon to Mercon V) but I don't know if the change was part way through the year or not. You dipstick should say what type to use.

If you need Mercon V then I would recommend sticking to fluid that meets Mercon V only and not a multispec type. This is my opinion only. I ahve not seen Mercon V only fluid anywhare but at Ford and the Mobil synthetic that I have seen meets the specificationis for Mercon/Dexron III but not Mercon V.
This doesn't mean that it is not available but I haven't seen it yet.

If you need Mercon V and you find one that meets this specification only then you should be okay.

I recently checked the fine print on the back of Mobil 1 synthetic ATF - and was surprised to note that it now claims to meet the Mercon V spec.

I don't know when the change took place; read the back of whatever you buy carefully.

I have seen warnings published about multi-spec fluids. But, based on the fluids I see stocked today, it appears that those concerns have been overcome by newer technology.

In my area, I have seen single-spec Mercon V fluid supplied by Castrol.

I recently checked the fine print on the back of Mobil 1 synthetic ATF - and was surprised to note that it now claims to meet the Mercon V spec.

I don't know when the change took place; read the back of whatever you buy carefully.

I have seen warnings published about multispec fluids. But, based on the fluids I see stocked today, it appears that those concerns have been overcome by newer technology.

I have a Mobile 1 Synthetic bottle left over from 2 years ago when I changed the clutch on my other car and it says "Mercon V" on the front label, not fine print. (The manual transmission on my other car uses Synthetic ATF.) I don't know what they look like these days but I'm going to Walmart these couple of days to check it out.

I need 7 1/3 quarts right?

Thanks Phil for pointing out the single-spec/multi-spec fluids. I will keep an eye on it and try to get only the single-spec fluids.

BTW, here is the mobil 1 ATF specs. They are multi-spec

http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobil_1_Synthetic_ATF.aspx

From what I herd, Ford will no longer sell Mercon tranny fluid and evey vehicle will have to eventually use Mercon V. Also, Mercon V is a semi-synthetic fluid (synthetic blend) which is better than regular Mercon. Mobil 1 is a full synthetic made of premium stock, so you will be fine.

Mobil 1 ATF changed from Mercon to Mercon V AND Mercon last year.
I think that you will see this dual labeling quite a bit as FORD is discontinuing the Mercon as of July of this year.
They issued a TSB stating that vehicles that specify Mercon may use Mercon V, and this is what is to be used in place of the Mercon.
This TSB supercedes the previous TSB's that they had issued saying not to do this.

Anyhow.... As FORD is now saying that Mercon V is the replacement for Mercon......you will see TRUE Mercon V labeled as being for Mercon V and Mercon applications.

Mobile 1 ATF is a quality fluid.....and will serve you well.
Remember to change it every 30K miles (normal service) or 21K miles (severe service).

Mobil 1 ATF changed from Mercon to Mercon V AND Mercon last year.
I think that you will see this dual labeling quite a bit as FORD is discontinuing the Mercon as of July of this year.
They issued a TSB stating that vehicles that specify Mercon may use Mercon V, and this is what is to be used in place of the Mercon.
This TSB supercedes the previous TSB's that they had issued saying not to do this.

Anyhow.... As FORD is now saying that Mercon V is the replacement for Mercon......you will see TRUE Mercon V labeled as being for Mercon V and Mercon applications.

Mobile 1 ATF is a quality fluid.....and will serve you well.
Remember to change it every 30K miles (normal service) or 21K miles (severe service).

My '98 with 83K miles probably still has the original fluid. How do you check whether it's the original or not, BTW?

I think Wiswind stated this but I want to paraphrase it to be sure:

Mercon V is the replacment for Mercon but
Mercon IS NOT a replacement for Mercon V.

I suppose this means that the power steering fluid should be switched to Mercon V (my 99 uses Mercon). I wonder if they can be mixed in Mercon Applications.

lidation -

Oops - You're right. I checked last night: "Mercon V" is printed on the front of the bottle (I seem to recall it didn't used to be this way...).

I think Wiswind stated this but I want to paraphrase it to be sure:

Mercon V is the replacment for Mercon but
Mercon IS NOT a replacement for Mercon V.

I suppose this means that the power steering fluid should be switched to Mercon V (my 99 uses Mercon). I wonder if they can be mixed in Mercon Applications.

:uhoh: Anybody can point out whether the Mercon and Mercon V can be mixed up?

Last month, I siphoned some of the old power steering fluid out and replaced it with Mercon V. I was planning to do this every month so that in half a year most of the fluid are new. But if they can't be mixed, that'll be bad. :disappoin

I just siphoned another 1/3 quart of PS fluid out (looks black) and put Mobile 1 Synthetic ATF in there. For safety's sake as not to have mixed up fluids, I will do this everyday for one week so that most of the fluid is composed of the new Mobile 1 Synthetic ATF. The siphone and the add fluid process only takes 10 minutes.

And for the transmission, from what I have read from here and from other forums (Wiswind and DRW1000 you two guys seem to be everywhere, lol), I will stick with the Ford Motorcraft Mercon V fluids. I'll probably buy 9 qt of those for the tranny.

There should be no problem with mixing the 2 fluids in a Mercon specified application.
Mercon V specified applications should have ONLY Mercon V or a fluid labeled as being for BOTH Mercon and Mercon V applications.

As to wondering if the fluid is original or not......."if in doubt, change it out"

The transmission capacity is 12.25 quarts......I would recommend a complete change.....as has been mentioned a few times here.
I would not do just a pan drop & filter change.....
I would drop the pan and change the filter....but I would follow the process to change out all the old fluid....replacing with new.
I have some step by step pictures and instructions in my pictures.

I just bought 9 qt of Motorcraft Mercon V Transmission Fluid from the Ford Dealer. It costs $5/each. Way cheaper compared to the beloved Mobile 1 Mercon V at $8/each.

I'll see whether I have time this weekend to do the tranny fluid change using the drop pan method. I bought a new filter and gaskets from AdvanceAutoParts.

If you do a thorough pump-thru change-out, you are gonna go thru something like 14 qts.

Note that the OEM pan gasket is reusable - and, to listen to others on this board, much higher quality than aftermarket gaskets.

If you do a thorough pump-thru change-out, you are gonna go thru something like 14 qts.

My current fluid is not burnt and looks bright pink so I guess a drop pan method should be fine.

Note that the OEM pan gasket is reusable - and, to listen to others on this board, much higher quality than aftermarket gaskets.

Thanks for the reminder! Yeah, Wiswind and others all say the original gasket is much higher quality than aftermarket ones. I'll keep an eye on that. If I accidentally damage my old gaskets I'll use new ones Else I'll just reuse the original one.