4th gear problems

[uNda6gT]

Hey everybody I have a 2002 grand prix gt and I'm on my 2nd tranny,I believe this 1 was rebuilt but not 100% sure,anyway when I'm cruising 1st 2nd and 3rd work fine but when I'm in the top of 3rd gear going into 4th it just stays in 3rd,now if I go Wide Open Throttle it goes into 4th with no problem...anybody have any ideas or suggestions on what it could be? Ay help is appreciated thanks!

 

[uNda6gT]

Anybody???

 

[Scimmia]

now if I go Wide Open Throttle it goes into 4th with no problem.

I think you have no responses because this makes no sense. It's shifting into 4th just fine at 130+ MPH?

Loosing 4th is very common on transmissions older than 2003, the splines on the clutch hub wear away.

 

[BillBoost37]

Right on with Doug. Makes little sense that the TPS must be working properly to shift the other gears and 4th should drop in easily with low throttle. Yet a WOT or even a 80% throttle should keep you out of 4th.

May be worthy to check your TPS just in case.

 

[uNda6gT]

TPS?????
so how exactly could i tell if its the 4th gear shaft?

 

[Scimmia]

TPS is throttle position sensor. The computer uses it to know when to shift.

First off, is it shifting into 4th at all or not? If not, it's a very good bet that it's the clutch hub.

 

[uNda6gT]

TPS is throttle position sensor. The computer uses it to know when to shift.


First off, is it shifting into 4th at all or not? If not, it's a very good bet that it's the clutch hub.

well this is the thing when i cruise it goes thru 1st gear,then 2nd gear then 3rd but it never goes into 4th but if im just cruising @ the top of 3rd and then just mash on the gas it feels like it went into 4th....i know it sounds weird but idk

 

[BillBoost37]

My thoughts is the best advice we can give you is to head for a trans shop and ask them to diagnose it. Seems as though you might not have a lot of experience with trans issues, which is making the internet diagnosis tough.