My TH400 came with a speedo gear already pressed on (I need to replace it with the reluctor). Anyone know if this can be removed with the trans assembled? Where do I get the "puller"?

 

U just need to remove the six bolts holding the tailshaft housing on.The old speedo gear is on the output shaft its only plastic and u should not need a puller to take one of,This can be done with the trans in the car. Hope that is some help i went and looked on my spare turbo 400.Damn 70 chevelle with a 540 big block aka "trans killer"

 

I came upon this thread due to searching for tool ideas for a front pump puller for a different trans.

Just wanted to say some TH400 drive gears were metal. Same removal ideas apply.

 

Late model 400 had steel gears PRESSED ON. Technically, I would use a puller to remove the steel gear, noting its exact location for the new exciter wheel. You can gently tap on the new exciter wheel with a heavy rubber mallet as you do not want excessive shock to the internals to cause brinelling. Hope this helps.