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post #1 of (permalink) Old 09-01-2005, 12:00 AM Thread Starter
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700R4 troubles

Well the Jeep and the truck are down now.

Anyone know why a 700r4 would all of a sudden no banging or crashes or anything that indicates a problem. The tranny just quit shifting from 1st to 2nd. I can rev the engine up and drop it into drive and it will go as if it just started out in 2nd gear. No shifting or anything like that. Just goes on in 2nd. Once in 2nd it shifts fine and runs down the road fine.

Any Ideas???
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post #2 of (permalink) Old 09-01-2005, 04:20 PM
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Re: 700R4 troubles

Well my dads the trans man i will have him post in when he gets home. look back around 7 or 8
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post #3 of (permalink) Old 09-01-2005, 09:01 PM
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Re: 700R4 troubles

Just to restate the phone convo......

deep breath in the nose and out through the mouth.........


TH400


[img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]
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post #4 of (permalink) Old 09-03-2005, 10:20 PM
 
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Re: 700R4 troubles

I would like to start by saying that I am by no means a professonal...... but I have experienced the demise of a 700r4 and watched the rebuild (and asked a lot of annoying questions while doing so)

The passages in the valve-body of a 700r4 are really small(not too much larger that an ink cartrige in a cheap bic pen) when you start to burn a clutch (usually the overdrive) the debris from the clutch can easily gunk up the valves to the point that they will not work. The first one in the sequence, between 1st and 2nd gear, goes first. (to further back up Dirt Dog's statement; the passages in a 400 are about the size of the outer diameter of the cheap bic pen itself....in exaggeration (a turd could pass through the valve-body of a 400.

Since shifting primarily relies on the pressure of the transmisson fluid passing through the valve-body, I could see how reving, and slamming into drive would produce enough pressure to open your gunked up #1 valve.

From what the guy that rebult my transmisson said, the three most common reasons that people kill 700s:

1) running really big tires w/o regearing (my problem)
2) towing w/o being really anal about maintenance (flush an fill w/ new filter)

3) plowing... period (that is about the meanist thing you can do to a transmisson)


most of the time all that really needs to be done to function properly is cleaning the valve system.... but if you have to pull the transmisson why not rebuild it (and besides the clutch that already started burning is not going to last that long.)

one of the things to look for if you suspect a burnt clutch is cloudy transmisson fluid that smells kinda burnt.
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post #5 of (permalink) Old 09-05-2005, 10:37 AM
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Re: 700R4 troubles

I am mach2's dad.I am a professional rebuilder.It sounds like you have a stuck gov valve or a valve stuck in the valve body.Before you attempt to do anything drop the pan and see if you have any debris.Metal or some burnt material.If you have any in excess the trans will have to come out.Some small amounts of metal around the magnet is normal.GM trans are notorious for generating some metal in the unit.Let me know
.
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post #6 of (permalink) Old 09-05-2005, 10:13 PM Thread Starter
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Re: 700R4 troubles

I am going to drop the pan tomorow. It started slipping the other day when I was trying to diagnose it. If it looked decent I ws gonna pull the governor, and go from there.
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