Need photo of mounting arrangement for driveshaft center bearing

[Lotus907]

Hello all
I have a 1986 Chevy K20 truck that I am in the process of converting from 4WD to 2WD. I have the rebuilt TH400 2WD transmission mounted in the truck and the original transfer case sitting on my spare parts shelf. The 4WD driveshaft was a one piece driveshaft that went from the back of the transfer case to the yoke on the input of the rear diff. But now I am looking to fit a 2 piece driveshaft from a C20 or C30 truck. What I would like to know is what the center bearing in the driveshaft mounts to. If anyone has a photo or photos of this center support for the center bearing in the driveshaft that would be really helpful.

Also if anyone has a 2 piece driveshaft assembly I would like to see photos of that as well. In particular I want to see what the front U-joint attaches to.

Thanks in advance.

BTW, don't know if it makes a difference but the truck has a 131.5 inch wheelbase.

 

[84GMCSierra]

This is my 84 C20, long bed. Hopefully you can see the U shape channel that the carrier bearing mounts to. I also added some pics of my transmission mount. I had the round one on it originally, but the new round one wouldn't tighten up, so I went with the rectangular unit. I think I got it from Rock Auto. Sorry they are on the dark side.

 

[84GMCSierra]

Here's some images from Rock Auto. The last pic is the transmission mount I used. Hope these help.

 

[Lotus907]

Thanks. That is the transmission mount that I have. The 4WD trans crossmember is quite a bit different so I had to make a spacer to go between the bottom of this mount and the 4WD trans crossmember.

 

[SquareRoot]

Why would one convert a 4wd to a 2wd and why would one want a 2 piece shaft over a 1 piece shaft.

 

[Lotus907]

The previous owner built the truck out of two trucks and the front diff ratio is 4.10 and the rear diff ratio is 3.73 so the front driveshaft has never been installed the whole time I have owned the truck. I don't use it for 4WD off road stuff so the transfer case was totally useless. When I had the TH400 transmission rebuilt I explained all of this to the rebuilder. He advised me to just go with a heavy duty 2WD trans rebuild and eliminate the transfer case. The stock driveshaft setup for a 3/4 or one tone 2WD drive C20 or C30 truck is a two piece shaft so this is what I am searching for.

 

[Lotus907]

This is my 84 C20, long bed. Hopefully you can see the U shape channel that the carrier bearing mounts to. I also added some pics of my transmission mount. I had the round one on it originally, but the new round one wouldn't tighten up, so I went with the rectangular unit. I think I got it from Rock Auto. Sorry they are on the dark side.

Hello 84GMCSierra
Thanks for all the photos. Can you tell me an approximate height of that U shaped bracket that is riveted to the crossmember of the truck's frame? I.E. the U shaped bracket that the center bearing bolts to. I am trying to figure out the angle that the driveshaft should be at in the truck. It looks like it is a different height in the front of the bracket versus the rear of the bracket to account for the slope of the driveshaft.
Thanks
--
Steve

 

[drumvirt]

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Steve,
I have more pics from different angles if you need 'em.

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[drumvirt]

Ha!
I'm not the best pic poster.

 

[drumvirt]

Pic of the front measurement of the midship bearing bracket depth.

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Also note that the driveshaft is 3 piece, with a shorty section behind the mid bearing followed with the rear longer shaft to the differential. The shorty allows for the deeper rear section drop.

 

[drumvirt]

Better pic of the rear side of the bracket.

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[Lotus907]

How different is the height of the front of the bracket?

 

[Lotus907]

So let me see if I am understanding this correctly. It looks like from these pictures that this U shaped bracket is about 4 inches in width (front to back) and at the back it is 3.375 inches deep and 3 inches deep at the front. Is that correct?

 

[84GMCSierra]

Hello 84GMCSierra
Thanks for all the photos. Can you tell me an approximate height of that U shaped bracket that is riveted to the crossmember of the truck's frame? I.E. the U shaped bracket that the center bearing bolts to. I am trying to figure out the angle that the driveshaft should be at in the truck. It looks like it is a different height in the front of the bracket versus the rear of the bracket to account for the slope of the driveshaft.
Thanks
--
Steve

Looking at the U bracket, it's 3.5" on the back side, and 3" in the front, as you said to account for the angle of the driveshaft. Hope this drawing helps.

 

[drumvirt]

I just double checked my U bracket (1985 c30) which is a slight bit shorter on the the back side than 84GMCSierra's '84. Mine is 3.375 as you said, Lotus907. Bracket steel is 0.375 thickness,

U shaped bracket is about 4 inches in width (front to back)

and it is 5 inches in width (front to back), and 8 inches across (side to side), with front and rear flanges 1 inch wide each.

Now 84GMCSierra, if you read this, can you tell me how to get my pics to show as small attachments as you've done. When I make the selection as "attachment", sometimes it still comes out large!??