ggardne2 wrote:
A 1988 5.0L is most likely not a C6 ... the C6 (which is a 3 speed automatic) was not commonly used on the 5.0L as it is a larger, higher torque capacity transmission that was more commonly used on the 5.8L, 7.5L, 6.9L and 7.3L diesels, and on the 4.9L I6. I suspect your van has an AOD which is a 4 speed automatic overdrive transmission. Regardless of a C6 or an AOD I would usee Mercon V fluid in your transmission.
The AOD never used type F and the C6 did not use type F after 1977 so do not use Type F in your van.
The Door Decal and VIN shows a AOT transmission.
TRANS T = AOT (Automatic Overdrive Transmission).
Mercon V is recommended from an online auto parts store for a 1988 E-150 with 5.0L V8. GM introduced the "Type A" ATF MERCON V. in 1997.
I've read of people using Dex/Merc II and Mercon V in Fords AOD transmission. Which apparently is a predecessor of the C4? I'm not really up on transmissions. My Jeep has a Asian/Warner AW4 which was designed to use Dex\Merc III. However when Chysler took over Jeep they eventually started to recommend to use their ATF+4 which most of the Jeep owners don't use as it causes the Jeep to shift hard. Jeepers who have owned Jeeps with the AW4 trans. for many years specifically recommend Dex/Merc III and never use ATF+4.
Google shows about AOD transmission.
The AOD (automatic overdrive) is a four-speed automatic transmission with overdrive. Introduced in 1980, it was Ford's first four-speed automatic overdrive transmission. The gearset design is based on the Ford "X" automatic transmissions used during the 1950s, 60s, and 70s.
https://en.wikipedia.org/wiki/Ford_AOD_transmission
Apparently prior to 88 or perhaps other years Dex/Merc. III ATF was used in Ford's AOD Transmission, then in 88 Mercon V started to be u sed?
I'm still trying to figure out what type of ATF Ford recommends, Mercon V? Mercon V is a synthetic blend.
Perhaps I'll flush out and replace all the old ATF with Mobile One ATF?
Specifications and approvals
Mobil 1 Synthetic ATF meets or exceeds the requirements of:
JASO 1-A
Ford MERCON® V
According to ExxonMobil, Mobil 1 Synthetic ATF is of the following quality level:
Allison C-4
General Motors DEXRON® IIIH
General Motors DEXRON® IIIG
General Motors DEXRON® IIE
General Motors DEXRON® IID
General Motors DEXRON® II
General Motors DEXRON®
Ford MERCON®
MAN 339 V1
Volvo 97340
Volvo 97341
Another alternative which I've used in my Jeep is Amsoil ATF which is rated for 100,000 miles and includes ATF specifications for all of the above plus other ATF types. Is also a multi-vehicle formula.
Amsoil is more expensive however it designed to last much longer. Though Amsoil recommends to change your ATF according to the manu. specs. It's designed to be used for up to 100,000 miles between oil changes.
I think if using Amsoil you potentially could double the length of time between oil changes if the manufactures recommendation is 50k or less.