Guys I'm just assembling a fresh SP400 Nailhead trans, and the std TH400 yoke fits onto the spline, but is too large in O/D. We have found out there is a difference, but we would like to know what the OD is of the Thinwall unit. I googled a search & found just one listing of 1.687". Before I turn down this std yoke, can anybody confirm a measurement on an (early 60's?) TH400 yoke?
why don't you just get a tailhousing from most any TH400 from about 1968 or newer? be a lot easier! edit: oh...you're in the land of no TH400s, sorry http://www.rockauto.com/catalog/x,carcode,1319419,parttype,8624 1.687 looks right?
cool, that's what we wanted to know . Figured it would be easier to leave my freshly built (& painted) trans intact, and turn down an old yoke.
I would have questions of the integrity of the turned down one. I hope it works for you, but I'd plan on getting the tailhousing and the regular yoke. Swapping it doesn't require anything more than unbolting it and putting the new one on. One of the things I always suggest when people get the ST400 or SP400 is the get the yoke with it.
I just crawled under my car and measured the part of the yoke that was sticking out of the tranny with my dial caliper and came up with 1.689". Only talking about .002 difference but that may be been dirt or paint. I'd cut it to 1.690 and polish it to fit.
Funny thing is when I took the last SP400 in to be rebuilt they put the newer tailhousing on it. I think they were confused when the seal in the kit didn't fit or something. lol. I had to then put the other tailhousing back on so I could put the driveshaft back in.
Lawrence!!! Just change the housing like I already told ya. Green paint won't make it reliable, do as you are told, transmission wrecker or you will be building it again. GM didn't change it for fun!! Or don't 401s make enough HP to break anything?
Plenty of T400s here, and parts too, Fish is just to stubborn to change it, thinks his green paint will save him from a flogged out slip yoke. Ask him how many cars he has..........now ask him how many have dead transmissions...........and all the cars are painted green!!!
One part number fits that early TH400. Spicer 2-3-5281X. To confirm, the snout outside diameter is 1. 683. Center of cap to tip of snout should measure close to 5 1/2". Getting hard to find, probably soon to be deleted as obsolete. The other option is to change the rear extension housing to a short later extension housing with the later 1.875 or so snout diameter. This more common bushing and seal ID can also lead to using u-joints as big as a '85 3/4 ton Chevy pickup if driveshaft strength is needed. NZ David Green has not bought any from me. He has bought the one that fits the later option, might still have. 2-3-10431x.
thank you for this info I have been hunting this yoke for several mo. every person said not ava. used this pn and bought one today, Thanks again.. Bobby..
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