During normal acceleration onto the highway, it goes through the gears just fine - except 4th. It just stays in third. I can "fix" it by quickly sliding it into neutral and back (foot off the gas). It will then immediately go into 4th.

Even more rarely, it will act up like this going into third. Same fix applies.

This occurs pretty infrequently (once a week, or so). What could be causing this? I adjusted the shifter cable this weekend, but the problem occurred again this morning.

This problem started after I dropped the Aux VB to repair a stripped bolt hole. I suspect an aluminum particle is interfering with the action of a valve or two.

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'87 IROC 5.7l TPI - original owner!

 

Not to complain, but I don't understand why I can't get any answers to this question. Does no one have even a clue as to what could possibly cause this behavior? Is my tranny just worn out and in need of a rebuild?

I would love to send my tranny to Pro Built or Transfixleo, but shipping it halfway across the country would be a major expense and PITA. How do I figure out which local shop really knows their stuff and will treat me right and truly do a first class rebuild that includes the best parts and upgrades?

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'87 IROC 5.7l TPI - original owner!

 

I would look at your Detent cable(Throttle valve cable) on your throttle body. Check that first. Then look into having a tranny rebuild. I just had to have my rebiult and i can say it's great to have a tranny rebuilt and running like a beast

Syxx

 

I am not sure what would cause this, I would check the fluid level first, adjust the TV cable as per transfixleo, make sure the TV cable slides freely. Have you done anything to the valve body (valve body kit?). How many miles on the unit?

 

This sounds a litte like the same problem I'm having.. how do you adjust the TV cable?

 

To adjust the TV Cable skip the book method and do this: Press the D button on the adjuster and loosen the cable setting. Now, have someone floor the gas pedal while you check to see if the throttle plate is open all the way. Usually they are off a little and will wiggle. Do whatever you have to do to get it open solid. Now, with the pedal still floored, press the D button and pull the cable casing (the black tube) back as hard as you can and release the button. You now have the engine, tranny and gas pedal all in sync at WOT. Mark the cable so if for some reason it gets moved you can know where to put it again. The problem with the 'self adjust method' is that it bends things and puts them permanently out of whack. It is also the full TV setting, which is theoretically what the GM method does.

 

Level's perfect.

I will do that today. I haven't messed with the TV system, so I don't know how it could have gotten off.

Yes, sorta. I merely dropped the aux VB to repair (drill, tap, and heli-coil) a stripped bolt hole.

I had it "rebuilt" (I question the completeness/thoroughness of the rebuild) at around 140K. It now has 230K.



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'87 IROC 5.7l TPI - original owner!