olenmarmcr
Registered Member
A friend of mine took his transmission apart and after putting it back together it goes forward in reverse and when you put it in park and turn the motor off it jerks forward. Its a 4l80e from a 95' 1 ton chevy dually.
CK5
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Ever gone forward in reverse?
- Thread starter olenmarmcr
- Start date
GsxrMike
1/2 ton status
Sounds like the linkage is out of wack.
olenmarmcr
Registered Member
it goes forward in all gears, seems like there's resistance when you give it gas too
GsxrMike
1/2 ton status
I change my mind then, he fuct it up!
olenmarmcr
Registered Member
lol obviously.
His forward clutch is seized.
I had that happen in my th400
It goes forward in every gear.
olenmarmcr
Registered Member
how do you get it loose?
Well on mine I had to replace it.
If he took it appart he probably put it together wrong, there are some rollers and some gears with springs, if he didn't know how to put it together right he could have screwed it up.
I haven't worked on a 4L80 but I believe they all are the same principal, cage with a gear inside it with rollers that ramp up on the gears and wedge between the gear and the cage and the whole setup becomes one piece, when the cage turns backwards the rollers are supposed to roll back and release but in his case they are stuck.
OK folks, I don't expect anyone here to believe this, I certainly have no proof, and I'm not sure I believe it myself.
I have asked several mechanics, and the few that would touch it said they thought it was possible.
Back in the 70s somewhere, I was in a hurry. I was working for the business my family owned, and I had several service calls.
We had this one chevy pickup, had to have about 150k on the clock. Standard shift, probably a 6, but might have had a small 8 cylinder under the hood.
I jumped in, cranked it, and it backfired. It had some bad plug wires, and was scheduled to rotate through our shop at the end of the week.
When it cranked, it was running way rougher than usual. I looked over my shoulder, put it in reverse, let out on the clutch, and bumped into the wall in front of me.
Thought, Idiot, you're in second.
Re-shifted, hit the wall again. Slowed down, made damn sure I was in reverse. It went forward.
Tried first, it went backward.
Man, I had had column shifts screw up before, but not like this.
Left it in first, switched it off and checked under the hood.
Sure looked like it was in first.
Cranked it back up, it ran a lot smoother. Did not touch the gearshift. Eased off on the clutch, it went forward.
Reverse went backward.
Now, did that, could that, engine start up and run backwards?
I keep thinking no, because the valves would be opening at the wrong times. But then I start figuring, and I'm not so sure.
It would not have to run well, it was just barely loping along.
But it seems to me that it would be sucking in from the exhaust and out the carb, but every-time I try to be sure my head hurts.
J.
I have asked several mechanics, and the few that would touch it said they thought it was possible.
Back in the 70s somewhere, I was in a hurry. I was working for the business my family owned, and I had several service calls.
We had this one chevy pickup, had to have about 150k on the clock. Standard shift, probably a 6, but might have had a small 8 cylinder under the hood.
I jumped in, cranked it, and it backfired. It had some bad plug wires, and was scheduled to rotate through our shop at the end of the week.
When it cranked, it was running way rougher than usual. I looked over my shoulder, put it in reverse, let out on the clutch, and bumped into the wall in front of me.
Thought, Idiot, you're in second.
Re-shifted, hit the wall again. Slowed down, made damn sure I was in reverse. It went forward.
Tried first, it went backward.
Man, I had had column shifts screw up before, but not like this.
Left it in first, switched it off and checked under the hood.
Sure looked like it was in first.
Cranked it back up, it ran a lot smoother. Did not touch the gearshift. Eased off on the clutch, it went forward.
Reverse went backward.
Now, did that, could that, engine start up and run backwards?
I keep thinking no, because the valves would be opening at the wrong times. But then I start figuring, and I'm not so sure.
It would not have to run well, it was just barely loping along.
But it seems to me that it would be sucking in from the exhaust and out the carb, but every-time I try to be sure my head hurts.
J.
As you already know, its not possible with the cam that would be in the motor. It certainly would be possible to grind a cam that could run the motor in the opposite direction but then it wouldn't run spinning the normal direction (clockwise).
Its simply how 4 stroke engines work, I have no explanation for your experience but I promise that its all but impossible for the engine to run backwards.
