700t trans problem

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  #1  
Old 08-27-03, 07:35 PM
razor45177
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700t trans problem

i have an 83 gmc full size truck with 150000 miles. was originally straight six with 700t trans. i recently mated this tranny up to an early model 350 and installed them both. the truck ran fine for a few days, but i went out to start it up this afternoon and came across a problem that baffles me. the truck will start up and idle fine, but when i go to put it into gear , nothing happens. the shifter will go through all the gears just fine, but it doesnt actually appear to be doing anything. the engine idle never changes, and just revs up as if it is still in park no matter what gear the shifter says it is in. under the truck inspection. the linkage is shifting the tranny just fine, and the flywheel and torque converter are both turning with the motor fine. i unhooked the linkage from the tranny and shifted through the gears on the tranny . they click through the gears and seem i stress seem to be alright. i was told the shifting mechanism in the tranny could be broke. does this make sense and is it hard to fix? i dont know what else it could be. like i said it ran and shifted perfect when i parked it in my driveway a day earlier. any help would be greatly appreciated.
 
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  #2  
Old 08-27-03, 08:38 PM
mike from nj
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pull the trans pan down---the shifting mechanism inside the pan consists of that same shaft as on the outside, connected to a small piece of metal and then a valve in the valve body.

i'm sure your problem will be obvious with it down

and put the e-brake on all the way and chock the tires too.
 
  #3  
Old 08-28-03, 03:48 AM
Joe_F
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I agree.
 
  #4  
Old 08-28-03, 03:23 PM
razor45177
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700t trans prob

any other ideas? i dropped the pan, everything is hooked up and seems to be working properly. think something major broke or could it be something else. like i said,it was fine when it was parked. the truck does recognize park and wont roll, only will start up in park or neutral, just wont move in any gear,,,what could cause this?
 
  #5  
Old 08-28-03, 03:59 PM
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Make sure the torque converter bolts are still there.Other than that the trans is most likely smoked.In my opinion it's not a good idea to take a trans with 150,000 miles and install a more powerful engine to it and think it will hold up.It could be something simple but I doubt it.The trans needs torn down if the bolts are in the converter.
 
  #6  
Old 08-28-03, 04:34 PM
Joe_F
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Arrow

150k on a pre 1989 700R4 in stock form is stellar.

Early 700R4s puke out and give up hope long before this mileage. Aftermarket and OEM rebuilds correct the problem with a revised pump and internal parts.
 
  #7  
Old 08-28-03, 06:33 PM
mike from nj
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what shade of brown is the fluid?

how much metal/glitter is in the bottom of the pan?

a 'straight six' trans will have less clutches and generally weaker gears and shafts than a 'v8' trans, even though it bolts up, it wasn't meant for this torque.

was the fluid topped off before you pulled the pan, low fluid=no go.

when you take it out, make sure there are (2)alignment dowels in either the engine or trans case, if none--the misalignment between the two (of even a few thousands of an inch) could have very easily sheared something inside the pump, resulting in what you have.

can you see the valve moving in and out of the valve body, the one connected to the shifter mechanism?? that's the little clip i was talking about--falling out. if that's working, then you have a definite trans problem like everyone said.

if you find another trans, the cable adjustment is VERY critical and could have caused this problem too(the cable from the throttle linkage)
 
  #8  
Old 08-28-03, 06:45 PM
razor45177
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trans prob

all this could have been caused by the detent cable ? how do i make sure it is set properly......gonna have to pull tranny and have it tore apart.......
 
  #9  
Old 08-28-03, 07:01 PM
mike from nj
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was it hooked up at least? (the cable)
 
  #10  
Old 08-29-03, 03:49 AM
Joe_F
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There are tons of sites on how to set up 700R4 cables out there. Do a www.google.com search for it...

A misadjusted TV cable will lunch a 700R4 in no time flat, it's probably the most critical adjustment.
 
  #11  
Old 08-29-03, 09:58 AM
razor45177
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tranny problems

thank you too all. yes the detent was hooked up,iam sure not exactly right, but it was hooked up. iam taking the tranny out today. thanks for everyones help and suggestions
 
  #12  
Old 08-29-03, 02:30 PM
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Make sure the filter isn't clogged or not seated all the way in. Also make sure the linkage actually moves the manual valve in the trans.
 
  #13  
Old 08-29-03, 07:55 PM
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You never said if you had the correct amount of fluid in when this problem occurred. I would definately check and add a little just to be sure before pulling even if it is a 30 minute or less job to pull it. Check with engine running.
Billy
 
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