Question..will be getting the truck here in ct this weekend after having lost a week to fedex delays trying to get the title...but he sent me some service records with the title. It looks like the plugs and boots were done around 50 k and its at almost 104 k so i know i need to change those out. But i asked about the tranny and he said it has never been touched/serviced..he said his mechanic said it's working smooth with no leaks and not to touch it...but at at 104 k , my instinct is to do a fluid exchange on it right away...any thoughts on this ?...thanks !

I would if it was mine.

I don't understand the thinking on the spark plugs. I changed them on my '03 E350 at 140k because I was there doing another job. It ran perfect and got the same MPG before and after. From personal experience with the 5.4 2V, it's no problem going at least 140k on plugs. The 5.4 3V is a different story. I will change those at 100k from now on. As for the trans, I'd definitely change the oil and filter. I believe the owners manual for the '03 said to do it at 60K?

You truck, do as you "think" is best. I don't let my spark plugs go much past 50K for a lot of reasons one being its a good chance to check for proper torque, inspect the boots and wiring harness connectors.

50-60K on the full ATF fluid exchange.

Yes...from what i have read on this and other ford forums, it seemed changing the plugs every 50 k was the way to go..and torque them to 20-22 ...i just ordered motorcraft plugs and mercon v from rock auto and should have those items done by next weekend.

Another question...i know that mercon v replaced mercon years ago. Is it necessary for me to drain out all the original mercon, as much as possible that is, before adding in the mercon v? I was planning on just doing the fluid exchange with the machine - mercon out - mercon v in - but some people i'm talking to are telling me it's not good to mix them..while others are telling me i may ruin the tranny with the new fluid..WTF !...i got 20 quarts of mercon v ready to go....how can this be bad?...thanks for any insight.

Nah, you will be alright specially with a full fluid exchange.

Dropping the pan will only get about 1/2 the trans oil volume, the other half lives in the torque converter. I know on some earlier models there was a drain plug on the TC.. don't know if that is the case here. If there is no drain plug then some other method of changing fluid might be a better option.

The TC drain plugs disappeared in the 2000 model year I believe. Regardless whether the drain plug is present the full fluid exchange is the best procedure for renewing ATF.

ALL E series Duallys are 4:10 open Carrier Dana 60's or 70's..If you live in a City like me definetely.... Add another Trans cooler in line with the stock one ... for when you are idling in Traffic .....And add a Guage..like JWA said....How much are you going to carry ? AND remember it is a Brick on wheels ..so forget about Fuel economy...I you get 6-8 it will be a Miracle...an Aftermarket Tranny Pan with a drain plug and a Reusable gasket would be a plus......When the Tranny Blows up ( and it will) just rebuild it with a Transgo valvebody and an upgraded convertor and you will be fine ...Good Luck

Well i know the tranny will go at some point but being that the truck box never had more than 500 lbs of cargo ever in it's life( the original owner who i bought it from said it never had more than a few couches/fabric chairs in it at one time), i'm hoping this 4r100 will last a good while more. But i will get a tranny temp gauge put in and depending on how the temp looks, may add another cooler...but i need to do the fluid exchange first and see where i'm at.
And i knew going in it would probably get 8-10 mpg..i can live with that as long as she's reliable and can help us make some money...but boy she is super clean..i got under it to change the oil ( 5w30 pennzoil ultra platinum / wix xp) and it literally looks like a new truck under there..and the interior is mint as well... will try to add some pics in the next couple days.

https://cimg2.ibsrv.net/gimg/www.for...5e1c463d52.jpg
Right after she arrived from florida

This is the only pic i have right now..this was right after my buddy arrived at my house in Ct with the truck from Florida.

Question that probably gets asked a lot...i just changed the rear differential fluid today. I bought Lucas synthetic 75/140 a while back from rock auto and finally got around to doing it.
It took 4 quarts but i did not any additional friction modifier to it since it is supposedly already in it...should i buy some and add it ?
Not really a Lucas fan but got it pretty cheap although i'll probably use Amsoil 75/140 going forward since we pull heavy loads almost daily with it.
This truck has been awesome for the year we've had it...thanks for any imput !

Would an ‘03 have a built-in ATF temp sensor that an OBD device can read?

Sixto
07 E350 5.4 178K miles