Rebuilt transmission, now getting knock at shifts?

[LEGACY_GN]

Nothing changed other than new clutches and bands in transmisison and rebuilt vigalante 5 disc from precision? What am I missing. What could be wrong. I checked and double checked all the bolts including the flywheel bolts. Everything is tight.

 

[mikestertwo]

There is probably nothing wrong. If the trans was freshened up the shifts are more likely a lot firmer increasing the load spike on the engine during the shift. This could possibly cause some knock.

 

[LEGACY_GN]

Well, it's registering up to 5 degrees on the scanmaster and setting off the audible knock detector, so it's going to hurt performance, right? Anything I can do to prevent that?

 

[mikestertwo]

Well, it's registering up to 5 degrees on the scanmaster and setting off the audible knock detector, so it's going to hurt performance, right? Anything I can do to prevent that?

Back the timing off a little or turn up the ALKY

 

[TexasT]

Those 5 clutch discs could be rattlin in there causing the sensor to pick up what it thinks is knock.

 

[LEGACY_GN]

No, I haven't run any boost yet. Just putting around town for the clutches to break in. Definitly not real knock. Also, the torque convertor use to rattle like marbles and now it's quiet as can be since the rebuild.

 

[Dave Dunbar]

Something left loose during installation... exhaust hitting something?

 

[626gn]

I had similar knock issues after having my trans replaced. Check to see if your transmission lines are against or very close to your crossover pipe. There should be a L-shaped bracket attached to the side of your trans that keep them from hitting the crossover pipe. If this bracket was removed it could easily be forgotten to be put back on or it could have been put back incorrectly. In my case it was put back incorrectly pushing the transmission lines towards the crossover pipe instead of keeping it away.

 

[LEGACY_GN]

I don't have a bracket and the transmission lines are far from the downpipe but very close to the crossover pipe, so will check that today.

 

[626gn]

You are correct. Meant to say crossover pipe.