1988 Ford E-150 Motorhome, lubrication

[Andonso]

I haven't worked on Fords for quite some time.

I have a 1988 Okanagan Class-B motorhome on a 88 Ford E-150 chassis, 5.0L V8 gas engine and I believe a C6 transmission.

I normally use a full synthetic motor oil with my vehicles such as Mobile One, either standard, extended or high mileage.

The C6 transmission I'm uncertain. I've read ATF types used are Type F, Dex/Merc III and Mercon V

Is there a better type of ATF to use with the C6 (4 speed with OD)?

A full synthetic ATF?

[ggardne2]

You have an AOD which is a 4 speed version of the Ford FX/MX/FMX based off of the original Borg Warner Cruise-Omatic. It uses a single Ravigneaux gear set and is not related at all to the C4 or C6 family which are Simpson gear set 3 speeds. The AOD was manufactured until 1992 at the Ford Livonia Transmission plant. It was replaced by the AOD-E which evolved into the 4R70W/4R75W transmission.

Any Mercon-V fluid will work well in this transmission.

[Andonso]

Assuming a re-builder didn't remove or install an incorrect tag.

If an AOD transmission, the first three-letter code on the top of the tag will say PKA (later AOD-E units with electric overdrives are designated as PKC). The AOD used two tail-shaft lengths; a shorter one for passenger cars had an E0AP casting, and the shorter truck castings read F2TP. The longer tail shafts had an E0LP casting on the passenger cars and an E0TP on pickups.

Below is a link to information about Ford transmissions.

http://www.fordification.com/tech/transID-auto.htm

[Andonso]

ScottG wrote:
Beware that if the trans has been rebuilt, it will likely use something different than type F if it were a C6. You can get a full synthetic in any ATF including Type F.

I don't think it can be a C6 because one of the difference between a C6 and AOD transmission is the AOD is 4 speed transmission using an OD gear.

From online search.

The C6 was included in the following engines: 300, 302, 351w, 400, 351c, 351m, 460, 6.9L, 7.3L, 352, 360 and 390. The AOD was only offered in the 300 and 302. The gear ratios for the C6 are: first -- 2.46:1, second -- 1.46:1 and third -- 1.00:1. For the AOD, the gear ratios are: first -- 2.40:1, second -- 1.47:1, third -- 1.00:1 and fourth -- 0.67:1.

AOD has a 4th gear which the C6 does not.

Trans Codes and Mileage

The trans code on Fords helps owners understand exactly what is under the hood of their car. Ford Motors has produced at least a dozen different types of transmissions, and the trans code helps owners decode which type of transmission their car has. The trans code for the C6 is "K" and for the AOD is "T." Because the C6 is capable of handling more power, it requires more power so the fuel mileage tends to suffer in trucks running the C6. The AOD typically offers better mileage.

My Trans code from VIN and door decal = T

There is also a tag on each transmission where one should be able to confirm the VIN code.



Appearance in the Instrument Panel

Ford trucks that came with the C6 transmission have the following shifting appearance: P R N D 2 1. The AOD models are: P R N (D) D 1.

Apparently if the transmission only has three gears it can't be an AOD.

I'm thinking of performing a passive flush, flushing out the old transmission fluid. One problem with ATF is if it sits a long time, even if stored in bottles, etc. it potentially oxidizes and looses lubrication properties and effects the performance of additives.

If you have a motor-home that's been sitting a while it's a good idea to flush out old ATF and other fluids because of oxidation.

Motor oil is the same way, for shorter periods of time. Most motor oils come with a yearly replacement change recommendation.

Many motorhomes often sit most of their lives. So things like fluids, tires, etc. may require changing before use.

[ScottG]

Beware that if the trans has been rebuilt, it will likely use something different than type F if it were a C6. You can get a full synthetic in any ATF including Type F.

[Andonso]

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.

[ggardne2]

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.

[theoldwizard1]

Motorcraft Synthetic Blend oil is plenty good and cheaper than any full synthetic. Just use the proper viscosity.

Type F ATF is long gone. Use Motorcraft Mercon V. Don't waste you money on a synthetic.

If that chassis is really 30 years old, I would replace ALL of the brake lines and hoses, the pads and shoes, calipers and wheel cylinders, springs and hardware. If you are going to DIY the brakes, use nickel-copper (NiCopp) brake lines. Easy to bend and flare.