Please Help With Transmission Problem!!

[BivDBO]

Hey everybody I am in desperate need of advice. I just swapped out my tranny for a T-45 out of a 98 cobra with almost no miles. I put it in and when I am sitting still with the clutch out I hear some gear noise. Also when I am driving and I downsift at a reasonable rpm there is a terrible gear noise that is radiating into the cab. This noise is only there when the clutch is pressed in. When I let the clutch out it dissapears. It happens in every gear but seems to be most apparent in 2nd. I have a new clutch, throughout bearing, and pilot bearing in the car and I don't know what else to look for. Any help would be appreciated greatly.

 

[OzzDOA]

Did you make sure it has the proper type and amount of fluid in it?

 

[BivDBO]

I think so I have 3 1/2 quarts of Royal Purple Syncromax in it. I filled it until it was coming out of the fill plug.

 

[OzzDOA]

Get that synthetic stuff out of there. Synthetics are a no-no on the T-45 and TR-3650 transmissions. User either Dexron III/Mercon as spec'd by the factory or Pennzoil/GM Synchromesh.

 

[BivDBO]

I will try that today and see if that helps. Thanks for the quick response.

 

[BivDBO]

Is there anything that I need to do to flush the transmission, or can I just drain the transmission and fill it with GM/Syncromesh?

 

[OzzDOA]

Keep in mind also that these transmissions can be kind of noisey. A bead of black RTV around the shifter base where it bolts to the trans or one of CobraBob's gaskets helps reduce the transfer of noise into the car as well.

 

[BivDBO]

Thanks I currently have one of cobra bob's gaskets on there now and it made a noticable difference.