U-joint for steering box

[Frank74K5]

Hi. First time posting.
My stock steering box was shot so I purchased the PWC box on Summit that was suppose to be a direct replacement. Turns out the output spline on the steering box that links to the steering column via a 3.25” u-joint is different. I’ve reached out to PWC with no return call. Anyone have a suggestion where to get the correct u-joint and what size spline PWC is using? Stock was 36 spline and the PWC box looks to be more like 40 but it has a flat portion on it so I can’t really get a good spline count.

Thanks for any help!

 

[Bent77]

Does yours have a stock steering shaft? If so what year?

Factory there are two different drive inputs, and the year split is 76/77

Also a link to the PWC part off of Summit. You have to lead me like a horse, I’m a bit daft

 

[Frank74K5]

thanks for the quick reply. the truck is 1974 K5 4wd
It is a stock steering shaft. Rectangular shape bar that has a smaller one that slides inside.
i bought the PWC steering box at summit. Not cheap. Here is the link. https://www.summitracing.com/parts/pfn-sgx442sr

 

[Bent77]

Count the splines on the new box again
Typically the earlier boxes are 30 spline, and after 77 are 36 spline
Despite what the guy replied on summit, I don’t recall the 1/2 ton shaft or boxes being different

 

[Frank74K5]

thank you!
ok. I’ll take a look. Hard to count splines on the new box when the shaft is not a complete circle. See the pics Of the new box. Sure seems like something PWC. Should be able to easily answer. The old steering box is definitely 36 spline.

 

[Bent77]

I mark it with a fine tip blue sharpie for the start point, and maybe every ten

 

[Frank74K5]

Thanks. Problem is this flat spot. There’s no way to count splines around the entire circumference of the spline. I’ll pull it out of the truck tomorrow and see if I can’t guesstimate. Sure seems ridiculous that the guys at PWC can’t answer what seems to be a simple question. I can’t be the first guy with this problem.
Thanks for your help. The guy on Summit may be right about it being 3/4 ton but I’m not sure that gets me any closer to the part I need.

 

[Wes Harden]

flat spot doesn't count. Your old one doesn't have flat spot ?

 

[Frank74K5]

Old one has a flat spot. I counted splines on the inside of the u-joint. Here is pick of old steering box.

 

[Wes Harden]

for a 74 k10 rockauto shows 17 19 25 and 31, we know 31 doesn't fit. if the flat spot is at 12 o'clock what position is the grove ?

 

[Frank74K5]

Groove looks to be at 9 o’clock

 

[Wes Harden]

More Information for DORMAN 31015

is my guesstiment

 

[Fastereddie]

Count the splines on the new box again
Typically the earlier boxes are 30 spline, and after 77 are 36 spline
Despite what the guy replied on summit, I don’t recall the 1/2 ton shaft or boxes being different

I think you have that backwards. Early is 13/16” diameter x 36 splines.
Later is 3/4” diameter x 30 splines

 

[70jimmy]

jeg's says 36 spline and 13/16

JEGS 60763: Power Steering Gear Box 1968-1976 GM K Series Trucks - JEGS

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[swettysblazer]

Comes up as a 70-76 box

 

[swettysblazer]

Could be someone swapped in a later box with shaft and lines?

 

[Frank74K5]

Thanks everyone for your help and insights. I’m going to order a 13/16 36 spline u-joint from Borgeson and hope it’s correct. I’ll let you know! THANKS AGAIN