1967 GMC - 305 V6 - TH400 Flexplate
 

I have a 1967 3/4 ton GMC with a 305 V6 and a TH400. The truck is completely stock and was handed down to me by my grandfather who was the original owner. The truck has one problem... it has a cracked flexplate and I need to get it replaced or fixed (it's cracked on one of the tabs where it's bolted to the torque converter). The problem is that I can't find a replacement flexplate anywhere! It's not your regular run of the mill 350 v8 style flexplate... it looks more like a 235 I-6 flywheel with a small triangular shaped flexplate attached to the back.

Does anyone know where I can find a replacement flexplate (used or new) for my truck? Has anyone else run into this problem with the GMC 305 V6s and automatic transmissions? Has anyone had any luck taking parts like this to a machine shop to get fixed? Can it be fixed? Any suggestions and ideas you have would be greatly appreciated. Thank you very much!

Re: 1967 GMC - 305 V6 - TH400 Flexplate
 

Go to the "6066gmcguy" website for a link to a company who makes auto trans parts for this engine. Once on site, click on Transmission Data, in the middle of home page. Automatics is near bottom of this page. Bendtsens Trans Adapters make have what your looking for.1966 GMC's also used the 305 with the TH400.

Re: 1967 GMC - 305 V6 - TH400 Flexplate
 

Thank you for the information, I really appreciate it. I'll look into it and post what I find out. Has anyone done business with this company? If anyone has an original flexplate to sell, please let me know. Thanks!

Re: 1967 GMC - 305 V6 - TH400 Flexplate
 

PM sent. Sharpie

Re: 1967 GMC - 305 V6 - TH400 Flexplate
 

Sharpie: Thanks for the PM... lets keep in touch.

As a side note, does anyone know if a Powerglide flexplate will work with the TH400 transmission with the 305 v6?

Re: 1967 GMC - 305 V6 - TH400 Flexplate
 

To see a cracked flex plate is not uncommon - especially to guys in trans repair shops - it happened a lot with some models.

Careful - if it cracks very much and enables play or vibration of the shaft and you drive too many miles that way it can begin to throw shavings and pieces inside the box - stuff gets pumped throughout and you will need a rebuild. Talk to a good trans shop - they know where to get them used and new - and they know which ones are stronger. Sooner is better.

Re: 1967 GMC - 305 V6 - TH400 Flexplate
 

Thanks for the advice! Are there typical reasons for cracks to develop on a flexplate?