Indexing bellhousing-is this necessary?

[Cincy123]

I have the gen 3 coyote power module and have run across occasional discussions on YouTube regarding indexing the the bell housing to make sure the runout is within tolerance. Is this something that most folks are doing?

[Sdonnel]

It is most certainly necessary. Would you trust the alignment of the crank shaft center line to the centerline of your bellhousing? If you're willing to pull the transmission to replace the pilot bearing, the option is yours. Personally, the first time I dialed mine in, I was at the limit and it vibrated like crazy. Second time around using the adjustable dowels allowed me to get it under .001". No more vibrations.

Scott

[NAZ]

A factory new engine "should" be OK but if you don't check how would you know? A good quality bellhousing manufactured on a newer and well maintained CNC machining center "should" be OK but if you don't check it how will you know? Everything that is machined has an acceptable tolerance and nothing is absolutely perfect. The variation around the target of each mating assembly combined is a variance stack up. If you don't check it how will you know your assembly is in spec?

[edwardb]

I don't know about the "most folks" thing. But as has already been suggested, highly recommended. I've done two Coyotes with Quicktime bell housings and they were in spec. But still need to confirm. I don't know how many people read the fine print, but Tremec actually says in their warranty that if not checked, the warranty is void. Coyote has different bushings than some engines (hollow) and offset bushings are apparently available. But I was fortunate enough to not learn about them.

[Rsnake]

I agree with everyone, you've got to check. I just did mine and uploaded the video on YouTube.
I was right at the limit .005. Not thrilled with the results but it's within specifications. At least I know.

[Cincy123]

Thanks all for the input. Definitely will plan on checking the index when it comes time to mate the transmission.