3800sc 4t65e no 4th (Page 1/1)
sdgdf AUG 22, 09:19 PM
Noticed my fiero with this drivetrain has been going into 4th less and less…. Checked out the Grand Prix forums and this is a common issue? https://tripleedgeperformance.com/no-4th-gear

Looks like less than $100 in parts but the cradle needs to be dropped? Anyone fix this on their Fiero?

Or I can just cruise in 3rd and tolerate the bad mpg? I get like 17mpg driving my 3800sc.

[This message has been edited by sdgdf (edited 08-22-2023).]

Raydar AUG 24, 12:23 AM
Edit - Sorry. Had to go and read the link.
Does it shift out of third into... nothingness? Or does it just never shift higher than 3rd?

As far as I'm concerned, automatic transmissions are just boxes full of witchcraft and sorcery. Kind of like mainframe computers.
Good luck with yours, whatever you decide to do.

[This message has been edited by Raydar (edited 08-24-2023).]

sdgdf AUG 24, 12:38 AM

quote
Originally posted by Raydar:

Edit - Sorry. Had to go and read the link.
Does it shift out of third into... nothingness? Or does it just never shift higher than 3rd?

As far as I'm concerned, automatic transmissions are just boxes full of witchcraft and sorcery. Kind of like mainframe computers.
Good luck with yours, whatever you decide to do.




It’s the slushest slush box I’ve ever driven. When 4th did work, whenever you let off the throttle it’d drop to idle. Like the torque converter either didn’t lock up or it’d constantly lock/unlock as you’d use the throttle. Real annoying having the revs drop and go up so much as you’d cruise. I’ve always figured it’s something to do with the tune on the pcm. Or maybe not the tcc lockup but it goes to neutral when you go off throttle in drive?

Right now it just doesn’t shift up beyond 3rd. Shifts perfect otherwise. These days I just keep it in 3rd because of the issue in the first paragraph, I like engine braking.
Mickey_Moose AUG 24, 08:47 AM
According to the info in the link posted, you will most likely have to drop the cradle and remove the transmission since it indicates that the unit has to be half taken apart to fix the issue.

But, you could just take it to a local transmission shop and get their opinion. If this is common, they should have experience with the unit and be able to tell you if it can be done in the car or has to be pulled.
sdgdf AUG 25, 05:09 PM

quote
Originally posted by Mickey_Moose:

According to the info in the link posted, you will most likely have to drop the cradle and remove the transmission since it indicates that the unit has to be half taken apart to fix the issue.

But, you could just take it to a local transmission shop and get their opinion. If this is common, they should have experience with the unit and be able to tell you if it can be done in the car or has to be pulled.



Ok maybe the transmission shop I know might work on a Fiero, guy swapped the manual trans in my daily driver for only $600 labor maybe he knows a trick to this.