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C6 transmission

  #1  
Old 10-07-2018, 07:42 PM
James Doty
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C6 transmission

As some folks know, my '85 Ford E150 conversion van which I bought last month has a C6 transmission in it, and it's not been working particularly well. Wouldn't go in to gear without giving it some throttle.

Today, after two days worth of work by a friend of mine I have the driver's seat raised up three inches, the pedals extended and a foot platform installed over the four inch dropped floor in front of the driver's seat. I can now transfer in to and out of the driver's seat unaided and can now use the van.

Until this afternoon I'd not driven the van yet. My father in law drove the van home from Portland, OR for me, some 33 miles, while I followed him in my '86 Caravan LE which is also wheelchair accessible and has cool gull wing style door on it. At any rate my father in law told me the transmission was slipping pretty badly.

And so it was, I drove the van from my house to a Safeway gas station some eight blocks away if taking the back roads, which I had, and it had to be coaxed in to moving forward again after each stop and continuing forward again after each turn.

While sitting in line, and with the transmission properly warmed up, my buddy from Port Angeles got out and pulled the transmission dip stick and read it, put it back, pulled it out, read it again, put it back, closed the hood and walked over and said "What transmission fluid".

So, after gassing up, we stopped at NAPA and put two quarts of transmission fluid in. It still wasn't showing on the dip stick. But driving home from NAPA (Half a block) the transmission never slipped once.

Got home, left the engine running and added one more quart of transmission fluid, it's now showing full enough that adding another quart would over fill it.

That said, I still need to take the van in to have the old fluid drained and the filter replaced but I'm happy. Because I now have to go buy two tires tomorrow for the front of the van. The left front tire goes flat in about two weeks. The other front tire is pretty bad so I'm replacing it too. The back tires are fair so I'm waiting another month to change those.

Still, yay on the transmission. I will be looking out for transmission leaks though.

The van sat in the last owners back yard for for years, I have no previous history though from when it was in Longview, WA. Sounds to me that it's possible no one bothered to ever check the transmission fluid level before or the didn't know how, or that they should.
 
  #2  
Old 10-08-2018, 08:42 AM
jbwheels
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I bet that is a relief. 3 quarts is a lot. Wow. Lucky it did not cook the clutches on the drive home.
 
  #3  
Old 10-08-2018, 09:07 AM
James Doty
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Yeah. I sure hope no permanent damage was done.
 
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Old 10-08-2018, 11:15 AM
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Drove my 96 f350 with c6 for a year with a leak that kept getting worse. I'd drive it till it started slipping, and put more fluid in. It would usually do so at about 3qts low. Usually about every 10 days.

went to pull it for a reseal, and found the issue. Broken case.





the other top mounting ear for the transfer case is broken worse, but held in by a pump bolt. Time for the zf5 manual swap to commence lol.
 
  #5  
Old 10-08-2018, 10:05 PM
James Doty
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Wow, that's really broken.

I'm thinking my C6 is leaking, I saw some new puddles this morning in the driveway. I guess I'll be taking the van in for transmission service on payday after all. I sure hope the leak's at the pan, I'm too disabled to crawl around under the van to look.
 
  #6  
Old 10-09-2018, 08:30 AM
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Yeah, no one I've shown it to has an explanation for why it broke there either. It was a plow truck for 80k miles so I assume that had something to do with it. The transmission itself was just fine. Shifted great when it had fluid.

I used a fancy 'lubelocker' gasket on my pan that seems really nice. I swapped to a summit deep aluminum pan before, hoping the pan was the issue. Obviously in my case, it wasn't.


 
  #7  
Old 10-09-2018, 05:28 PM
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Originally Posted by James Doty View Post
Wow, that's really broken.

I'm thinking my C6 is leaking, I saw some new puddles this morning in the driveway. I guess I'll be taking the van in for transmission service on payday after all. I sure hope the leak's at the pan, I'm too disabled to crawl around under the van to look.

If it's leaking there are a few areas it could be. Most common leaks will be: Pan gasket, front seal or output shaft seal. The pan gasket is the easiest/cheapest to fix ( besides dipstick O-ring ) . If it's the issue, it's not a bad idea to just have the transmission serviced ( drop pan/drain transmission, replace filter & pan gasket ) . If it's the rear seal make sure they also check the tailshaft housing bushing for wear. If the bushing is worn it can let the slip yoke move around more and cause the leak. To change the bushing and seal they need to pull the driveshaft, support the transmission, remove transmission crossmember & speedo cable, unbolt the tailshaft housing then change seal and bushing. Then reassemble. The front seal is the cheapest part but most expensive fix. They have to pull the transmission to fix it. This is a fairly common leak on a vehicle that has sat for a while. I've had a few vehicles with this leak that sealed back up after driving it for a while. Then others that just leaked worse until the sealed was changed.

The other common area for a leak is the transmission cooler lines/hoses. The hoses can crack/blow out and the hard lines can rust thru. But usually when it's the cooler lines it's a major leak that is hard to miss. Unless you are lucky and it's just a loose clamp at the cooler. You wouldn't make it very far driving it with a major cooler line leak.

I have also seen them leak out past the dipstick tube at the case. This is from a bad O-ring. It requires pulling one bell housing bolt lifting the dipstick tube out of the case, clean it up/remove old O-ring if it's still there, Lube and install new O-ring and reassemble.


You can usually get an idea of which area is leaking by where the drips are under the van. At the front of the van would be transmission cooler or lines/hoses. If the drip/puddle is under the center of the van about at the front of the front doors it's probably the front seal. Anywhere in the front door area of the center of the van could also be pan gasket. behind the front door area would be the rear seal.




Originally Posted by BigBlue 94 View Post
Yeah, no one I've shown it to has an explanation for why it broke there either. It was a plow truck for 80k miles so I assume that had something to do with it. The transmission itself was just fine. Shifted great when it had fluid.
I would say it had to do with the plowing.
 
  #8  
Old 10-09-2018, 05:37 PM
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Originally Posted by fordman75 View Post

I wonder if that damage wasn't from the 4wd. Any hard trail/mud use or 4 LO launches? Heavy towing? Or could just be a fluke or casting imperfection, stress riser crack.
it was leaking already when I got it. I've not put a ton of miles on it, maybe 8k. It was a Kansas City MO snow plow truck for about 80k miles. My only considerable guess was from that, and it would've been in 4wd at that point. Transfer case and adapter are perfectly fine. Plus it was a 96, so it was bound to be the best casting design. It does have a bw turnover ball in the bed (gooseneck trailer hitch) but idk how much it was used. I believe im the third owner after KCMO, so it's hard telling what this truck has been through. No lift, 33" tires.

pretty interesting spot to break eh?
 
  #9  
Old 10-09-2018, 05:44 PM
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Nothing really surprises me. I've seen plenty of 4x4 ZF 5spd's that like to break transmission mount ears on the transfercase adapters. I would say your damage was probably from the plowing. Plowing can put a lot of force on a lot of parts. Pushing heavy loads and sometimes coming to abrupt stops while doing it.
 
  #10  
Old 10-09-2018, 05:54 PM
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Originally Posted by fordman75 View Post
Nothing really surprises me. I've seen plenty of 4x4 ZF 5spd's that like to break transmission mount ears on the transfercase adapters. I would say your damage was probably from the plowing. Plowing can put a lot of force on a lot of parts. Pushing heavy loads and sometimes coming to abrupt stops while doing it.
don't say that lol! A zf5 is replacing that c6. Imagine what hitting a curb with a plow does at even 10 mph. That can't be good on the truck.

hijack over...
 
  #11  
Old 10-11-2018, 11:28 PM
James Doty
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It appears to be leaking about in line with the front of the doors. So either the pan gasket, dipstick o-ring, or front seal. In any event I'll have the filter replaced but with my luck and the age of the van my money's on the front seal.

I'll make an appointment to have it looked at in a few weeks.

At least I'm able to drive the van now. It sat in my driveway for about a month before I got help setting up the front seat so I could drive it, then the next work day I got two new tires for the front, so plenty of progress.
 
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Old 10-12-2018, 09:07 AM
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Not trying to pry details, but do you have use of your feet for the pedals, or use hand controls? My uncle use to be able to use his feet, but his condition has deteriorated and he is stuck using hand controls.
 
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Old 10-12-2018, 09:12 AM
James Doty
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I use my feet. It's a common question. I walked until I was 13, rode a bike until I was 18, was able to crawl around under cars and such until I was 45. Now I can't get back in my chair from the floor so no more of that.

I have hand controls in my '86 Caravan as well. In heavy traffic I use the hand control for braking, beats all that moving the right leg around constantly thing.

Someone removed the control rod for the throttle on my Ford, I'm planning on correcting that. I don't want to remove the hand controls because of their value and what if someone else, including me, needs them in the future?
 
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Old 10-12-2018, 09:54 AM
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Thats kinda how my uncle was. He could walk into his 20s. He could shuffle around to get in the van or into bed, etc. Not anymore, now that he's retired. Spent 20+ years in the adaptive tech dept at a local association for mentally and physically challenged. He built so many things to better the lives of those kids and adults who can barely help themselves.

Definitely don't get rid of the hand controls. You can bet you'll probably need them down the road, and not having to shell out tons of cash will be nice.
 
  #15  
Old 10-12-2018, 10:35 AM
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You might want to replace the vacuum modulator also as it is an unseen place for the ATF to get burnt by the engine.
It screws in at the back of the transmission.
 

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