4th Gear Slightly Slipping

[electraglide]

Hi all. have a 99 C5 convertible automatic, and since changing out the lame 273 rear gears to 342,s I have this slight slipping in 4th gear. Never noticed it before the change. After this happens a few times it shifts very fast and hard from 1st to 2nd. Then I reset the codes and it's ok. Have a rebuilt tranny waiting to go in just in case that is what the problem is. just do not understand why it is happening after the rear gear change. any info would be great.

 

[12cents]

Did you change the torque converter to a higher stall? That is the only thing I can think of outside of a tranny problem.

 

[electraglide]

No, I did not change out the torque converter, but will be if the rebuilt tranny has to go in. I just do not understand why it was fine before the install of the 342,s.

 

[1st Vette]

No, I did not change out the torque converter, but will be if the rebuilt tranny has to go in. I just do not understand why it was fine before the install of the 342,s.

Just a shot in the dark but could it possibly be because of more load on the drive train due to the diff change ? Although that doesn't necessarily explain why only in 4th gear......