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C6 Service

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mp470

C6 Service

The fluid is pretty low and completely black. Pan leaks slowly, gasket is definitely shot. I've heard these are robust transmissions but I have no idea about the history of maintenance, probably little to none. I've got everything for the service, just thought I'd throw it out there to see how it might react to new fluid (slippage, hard shifts etc.). This will just be a pan drop, not a flush. It still shifts quite well unless it gets down to freezing, then it won't go out of 1st until after a few circles around the block.

Slightly related note, the transmission mount is so worn it's basically just metal on metal. Best practices for replacement...undo the nuts, jack up on the pan with a block? Or is it much more complicated?

1985 F-150 XLT Lariat, 5.0 EFI, RWD, 8.8 Axle

Gary Lewis

Re: C6 Service

Administrator

Changing the fluid, filter, and gasket isn't too bad - with the exception of the draining part. From the factory there's no drain plug so you have to guess which corner is low, loosen the pan bolts, and pry that corner down to get as much out as you can. And then drop the pan. Be prepared for a big mess.

Don't forget that the torque converter holds as much fluid as the tranny itself. So you really need to drain it as well. There's a little pipe plug that drains it, and you need to pull the inspection cover and rotate the engine until that is at the bottom. Pull that to drain it, then put it back and it'll be filled when you fill the tranny.

The pans are somewhat flimsy and over-torquing the bolts dents them, so check the pan to see if it is dented and, if so, use a small ball pein hammer to work the dents out. And when you put the pan back don't over torque it. I like to use a good layer of RTV on the gasket, put the pan on, snug up the bolts by hand, and let it sit over night for the RTV to cure. Then torque it to specs, fill it, drive it, and check the level as it'll be a bit low. But if you put RTV on and try to torque it down then the gasket will squirt out the sides due to the slipperyness of the RTV and you'll have a leak.

On the mount, I'd put the jack under the tail housing or transfer case rather than the pan. As said, those pans aren't the most robust so I don't like to jack on them. But, if you put a piece of wood about the size of the pan between it and the jack that will spread the load and it'll be fine.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Bruno2

Re: C6 Service

If you are changing fluid it probably wouldn't be a bad idea to add a filter on the return line. New fluid with fresh strong detergent breaks loose stuff in the radiator and cooler.

Whitey: 1996 F 250 XL CCLB 4X4 7.3 DI ZF5 (The Work Horse) Lots of power mods
Whitey Jr: AKA Jr 1982 F 150 CCLB 4X4 351W C6 (Jr Work Horse) respectable power, but not over the top
The Bronco: 1987 Bronco XLT 351W C6 (needs work) Lots of off road mods and plenty of power mods
The Dodge: 2006 Ram 2500 CCSB 4X4 5.9 HO Cummins (The reliable ride that cant keep an AC in itself) (5th AC go around almost complete)

JMUBullnose

Re: C6 Service

In reply to this post by mp470

Interesting! I was just contemplating rebuilding the AOD this winter on my Ford. Good winter project as I don't use the truck much during that time.

1984 F-150, 302 CID (5.0 L) Windsor V8, 2 BBL carb, power windows added, remote entry added. AC. Automatic Transmission.

mp470

Re: C6 Service

In reply to this post by mp470

Well the service is done, somewhat. Being a weeknight, didn't have enough time, so didn't drain the TC. The fill was messier than the drain, that tube holds the funnel too horizontally and it fell a couple of times, sending fluid everywhere. Drained about 4.5L out of it so it was definitely low. The black stuff I saw on the dipstick was just the fine metal particles at the bottom of the pan. The fluid itself wasn't too terrible, although dark.

Thanks all.

1985 F-150 XLT Lariat, 5.0 EFI, RWD, 8.8 Axle

Gary Lewis

Re: C6 Service

Administrator

Did it change the shifting?

Gary, AKA "Gary fellow": Profile

mp470

Re: C6 Service

I haven't driven it yet, it still needs more fluid. It got a bit too dark out to finish last night.

1985 F-150 XLT Lariat, 5.0 EFI, RWD, 8.8 Axle

Ken Blythen

Re: C6 Service

Given the condition of the fluid , I would REALLY recommend draining the converter; it can still be done if the engine hasn't been started.
You can also disconnect the cooler lines & gently push the fluid out of the pipes & cooler with compressed air (just light pressure).

The whole refill is about 12 quarts, so there is still a lot of contaminated oil in there, mainly in the converter.

Gary Lewis

Re: C6 Service

Administrator

Excellent point, Ken. Just turn the engine slowly with a 15/16" socket on the crankshaft bolt until the drain plug is at the bottom, pull it to drain the converter, and then refill things when the plug is back in.

Gary, AKA "Gary fellow": Profile

mp470

Re: C6 Service

In reply to this post by Ken Blythen

I had already started the engine at that point for the hot check, will do it next time.

Took it out for a highway cruise, runs like a clock as usual, shifts perfectly. It's incredible that this 33-year old vehicle has perfectly working cruise control.

Only complaint is the low oil pressure at hot idle but not much to be done about that, will throw some Rislone in it and hope for the best. Crankcase pressure is high, blow-by to the airbox and out the PCV valve hose etc. I wish I had the time, money and place to really dedicate to rebuilding the engine, body etc. For now, it's just a camping truck for 1-2 seasons of the year.

1985 F-150 XLT Lariat, 5.0 EFI, RWD, 8.8 Axle

Gary Lewis

Re: C6 Service

Administrator

Be careful with the Rislone. In my experience it thins oil and cleans things. So, I'm not sure I'd use it for low oil pressure. Nor on an engine that might be really dirty inside - assuming the transmission's lack of maintenance is any indication.

David/1986F150Six had an instance last fall where his clean oil over the years stripped the sludge out of the engine and partially plugged the oil pump's pickup screen. So you want to go slowly on the cleanup.

Gary, AKA "Gary fellow": Profile

1986F150Six

Re: C6 Service

Administrator

Apparently, the displaced sludge was lurking somewhere and when the fuel pump started leaking internally, the gasoline caused the sludge to break loose and as I drove, the sludge blocked the pickup screen for the oil pump.

Gary Lewis