Just had a TH400 transmission built from a 1 ton chevy, Had a bolt Yoke (Which I have) but wanted to use a capped off yoke (NO BOLT) exact same yoke dimensions but use as a slip fit instead of 2 piece drive shaft.... Is this OK ??? cant get a answer even from ****** shop ??
Yes. I did this on my transmission. I used a yoke from Denny's Driveshaft, made specifically for this application. https://www.dennysdriveshaft.com/c1284_32_spline_truck_transmission_t_400_4l80_4l85_.html
There is a rather spendy (for my wallet) slip yoke designed specifically to be used with the output shaft that had a bolt on yoke. https://www.dennysdriveshaft.com/p6...lip_yoke_1310_series_32_spline_wth.html#photo. It looks like it is sold out and it may be an exclusive item for them but I'd say that this answers your question. Double pumper beat me to to the draw on that one.
A conversion yoke for this requires counterboring the spline end to enable enough clearance for rear end movement. The T-400's with bolt-on yokes use a different output shaft and won't allow for enough movement when using a typical slip yoke without it having been bored for clearance.
Mine must have been a Unicorn then... all I did was replace the bolt on yoke with a slip yoke and all was good. No leak's, no vibration...
Truck bolt on yoke is the same length as a short tail 400. There will be an o-ring on the tail shaft that sealed the bolt on yoke, that you may have to remove, depending on the new yoke type. Bill
I'm going to say, the need to have a long enough yoke slipping over the shaft is probably the concern, that followed by enough free play to slide when the arc of travel changes. You don't want it to stubb out, or fall off.
I went through this, stopped at Denny's and after about the 3rd insult from that ***** I told him how much of an arrogant ***hole he was and got one from Inland Empire Driveline without issues and in stock. https://www.iedls.com/ This is what the difference looks like, the smooth part rides on the "O" ring seal on the output shaft to seal the fluid in.
I did the exact same thing you did on my O/T Nova bracket car. The transmission I had built with a full manual valve body came out of a GMC 3500 van.
I too bought the thicker case th400 with straight cut gears out of a cube van for it's stronger attributes, on mine the regular slip yoke would only go in a couple inches before it ran into the "O"-ring stopping it.
As has been stated , yes you can switch yokes no problem. But if the trans had a o ring the plug in the end of the yoke would have a small hole drilled in it. So be aware of that or you can end up with a leak. Here are a couple of my posts showing some differences you can run into.
Not that I'm the answer to the problem, just that I like to see the problems before I think I've solved them. Transmission tail shaft or drive shaft length with suspension travel? I was thinking out loud that since there is a range of spline to be grabbed, as long as it doesn't bottom out, or fall off, your probably close to golden. That being with the understanding that the reason it's bolted is because the other end of the first drive shaft allows for movement. I'm curious, does the part number for the rear seal change? Looking at the grooves from the seal, I could see a few minutes spent thinking about the positioning of it on the out put shaft?
That was one of my questions at Denny's, I ask how it could be just as strong as a regular yoke (as he claimed) when there was a significant amount of spline loss with it being shorter and no splines on the end. That led to my second question of yoke slippage during suspension travel and having less spline engagement in the special yoke, his reply was that the yoke only moves an 1/8 inch during full travel. I ask why does it move more than that when I jack my car up and the suspension droops ???
""I ask why does it move more than that when I jack my car up and the suspension droops ???"" Because your suspension main pivot point is too far away from the front pivot point of the u-joint. Fore and aft is not as critical as up or down, but I would worry about what its doing driving around.
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