C6 trans issue
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C6 trans issue
I have a 1986 F250 6.9idi with a c6 trans.
Recently, the transmission doesn't engage when I start and put it in Drive (or 2 or 1); however, it works fine and engages well in reverse. This morning, I drove it a few miles and then parked it for 30 minutes or so, and when I came out to leave, I had to rev the engine up for about 2 minutes before it began to engage.
It shifts well once it gets going (not too hard, and not too soft), pulls well, and runs well.
The fluid is at proper level and is clear and red as it should be with not burnt smells.
What in the world can this be?
I would think if it were a pressure or clogged filter issue, reverse wouldn't engage either.
Any ideas guys?
Recently, the transmission doesn't engage when I start and put it in Drive (or 2 or 1); however, it works fine and engages well in reverse. This morning, I drove it a few miles and then parked it for 30 minutes or so, and when I came out to leave, I had to rev the engine up for about 2 minutes before it began to engage.
It shifts well once it gets going (not too hard, and not too soft), pulls well, and runs well.
The fluid is at proper level and is clear and red as it should be with not burnt smells.
What in the world can this be?
I would think if it were a pressure or clogged filter issue, reverse wouldn't engage either.
Any ideas guys?
Lead Driver
Joined: Dec 2006
Posts: 6,496
Likes: 94
From: So. Jersey
Clutch assembly could be burnt or the forward clutch stator support seal rings leaking. Also could be valve body sticking or overtorqued bolts if you had done a filter change lately. Also check the linkage.
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Are you referring to the filter bolts being overtorqued? Mechanically, what does that do that makes it malfunction? What are the signs of a clogged filter?
Help me understand the linkage......Wouldn't it at least be in one of the forward gears if I manually shifted it into 1 or 2 from Park? Nothing seemed to work yesterday. What is the process for checking/adjusting the linkage?
Also, on this cold morning (32), I started the truck and shifted through both Reverse and Drive, and it engaged normally in both ?????? Why didn't it work when the truck was driven and warm later?
Love my truck....gotta get this fixed before something major happens.
Thanks guys.
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c6 slipping
OK guys...I'm hoping there's a C6 expert out there.
I jumped in the truck this morning to start it and let it warm up. I then proceeded to shift to "R", and had engagement. I then shifted to "D" and had engagement.
Then, after about 15 minutes of it sitting in the driveway warming up, I get back in the truck and it won't engage in D, 2, or 1. But R is engaging.
I had to rev it up to 2000 rpm, and then it creeped to a start (kind of like starting with a clutch on a manual transmission )
What is wrong here? This is a fairly new truck to me....If my transmission is shot, would it engage when it is cold? Could it be a band adjustment? If so, does anyone have any pics of how to do this?
Thanks in advance for helping a brother out!
I jumped in the truck this morning to start it and let it warm up. I then proceeded to shift to "R", and had engagement. I then shifted to "D" and had engagement.
Then, after about 15 minutes of it sitting in the driveway warming up, I get back in the truck and it won't engage in D, 2, or 1. But R is engaging.
I had to rev it up to 2000 rpm, and then it creeped to a start (kind of like starting with a clutch on a manual transmission )
What is wrong here? This is a fairly new truck to me....If my transmission is shot, would it engage when it is cold? Could it be a band adjustment? If so, does anyone have any pics of how to do this?
Thanks in advance for helping a brother out!
Senior User
Joined: Feb 2006
Posts: 244
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From: Texas
I am no expert on these trannies, but it doesnt sound good. The good thing is the c-6 is inexpensive to rebuild or replace (you can find them all over the place). It would be hundreds of dollars, instead of thousands that the newer fancy transmissions would cost.
Elder User
Joined: Apr 2002
Posts: 950
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From: West Bend
I've had a similar with my gas C6 (actually 2 different times). I'd say check your shift linkage. If one of them plastic bushings falls out or wears out with too much slop in it your trans won't shift into into it's gear detent while the shift column IS in it's proper location. This puts your trans "between gears" and gave me a similar issue. If it's slipping try moving the shift lever up/down just a bit.
Aside from that, I've had it slip going forward and nearly lost reverse a few times when my transmission overheated when I was plowing this winter. She's old and worn out, does the 2-3 slide and burns up the oil in under 100 miles. When I last had it apart I adjusted the bands and the adjustments are pretty much all bottomed out. Fortunately this will all be a non-issue when I get the 6.9 swapped in it with a new C6. Even upgrading my Borg Warner transfer case to an NP205.
Chris
Aside from that, I've had it slip going forward and nearly lost reverse a few times when my transmission overheated when I was plowing this winter. She's old and worn out, does the 2-3 slide and burns up the oil in under 100 miles. When I last had it apart I adjusted the bands and the adjustments are pretty much all bottomed out. Fortunately this will all be a non-issue when I get the 6.9 swapped in it with a new C6. Even upgrading my Borg Warner transfer case to an NP205.
Chris
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