700r4 problems - Third Generation Pontiac Firebird (1982 - 1992) - Firebird Nation

Jump to content


FirebirdNation.com is the premier Pontiac Firebird forum on the internet. Supporting Members do not see the above ads.
Photo
- - - - -

700r4 problems


  • Please log in to reply
3 replies to this topic

#1 86tpi

86tpi

    Firebird Newbie

  • New Member
  • Pip
  • 2 posts
  • Gender:Male
  • First Name:Zack
  • City:Valencia
  • State or Province:CA
  • Country:USA
  • Year: 1986
  • Make: Pontiac
  • Model: Trans am
  • Engine: 305 5.0l
  • Transmission: 700r4 automatic

Posted 3 weeks ago

I have a 1986 trans am 305 with a 700r4 transmission and when I am cruising at highway speeds (70-80mph) the car will down shift out of 4th and into 3rd for no reason. I then have a hard time getting it back into 4th without it dropping back down to 3rd. Any ideas on what might be going on?

#2 sea dog

sea dog

    Firebird Master Tech.

  • Administrator
  • 2982 posts
  • Gender:Male
  • First Name:Robert
  • City:Fruitland Park
  • State or Province:FL
  • Country:USA
  • Interests:cars, guitars, women, firearms,
  • Year: 1995
  • Make: Pontiac
  • Model: transam
  • Engine: 5.7 lt1
  • Transmission: 4l60e

Posted 3 weeks ago

Are you sure that trans is dropping into 3rd? I ask because 700r4 equipped cars suffered from lock up hunting back in the 80's through the early 90's. The trans, under many driving conditions would unlock the torque converter, which feels like the trans is shifting down from 4th to 3rd.



#3 86tpi

86tpi

    Firebird Newbie

  • New Member
  • Pip
  • 2 posts
  • Gender:Male
  • First Name:Zack
  • City:Valencia
  • State or Province:CA
  • Country:USA
  • Year: 1986
  • Make: Pontiac
  • Model: Trans am
  • Engine: 305 5.0l
  • Transmission: 700r4 automatic

Posted 3 weeks ago

Im not too sure to be honest with you. I just know that it bumps the rpm up to 4K and I have to let off the throttle to let it shift because for some reason my cars gets zero power above 4K rpm. Feels like it doesnt go anywhere

#4 sea dog

sea dog

    Firebird Master Tech.

  • Administrator
  • 2982 posts
  • Gender:Male
  • First Name:Robert
  • City:Fruitland Park
  • State or Province:FL
  • Country:USA
  • Interests:cars, guitars, women, firearms,
  • Year: 1995
  • Make: Pontiac
  • Model: transam
  • Engine: 5.7 lt1
  • Transmission: 4l60e

Posted 3 weeks ago

Usually the torque converter unlocking  would raise rpm by 500 to 700.

 

About your 305 lacking power over 4000, is your 86 a carb car or is it tune port fuel injected?  During early to mid 80's carb equipped engines were pretty pitiful and frequently ran out of the power band in the 4000 to 4500 rpm range.

 

Has your engine had a complete tune up recently? New rotor, distributor cap, plug wires & plugs would return much lost performance. Especially with new air filter, fuel filter, and a minor rebuild of carb.

 

If engine is a tpi version, the tune up suggestion would help also. The tpi cars were very lively compared to carb cars.






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users