Tailshaft / Driveshaft yoke - how far out from the housing is ok?

[BRetty]

All,

I feel like my tailshaft is sticking WAAAY too far out of my 9" tailpiece on my th350c.

This pic is with rear wheels on the ground, front jacked up so front wheels are just off the ground.

That's 1.75" exposed. ???

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[Rusty Nail]

Looks like a bunch to me too. That part isn't much longer than that either..you oughta take the driveshaft loose at the rear-end and see how much contact it's actually making. Put some tape on it or something to mark the spot and you'll need something to catch the little bit of trans fluid that will follow it out. I bet there isn't an inch of conract inside there!

Good lookin out. Reckon that is fhe incorrect part installed. A different part will be your solution.

Not like it's the end of the world but most guys like sleeping easy.

I bet @Awoschmotors has one he'd sell ya. I don't have an extra.

 

[DoubleDingo]

It looks the seal has been riding between where the seal is now and where the weld is. What has changed for the yoke to come out that far? Just jacking up the front tires? What's it look like with all four on the ground? Just having the front jacked up should not make a difference, but who knows it might.

 

[Rickf]

You may be in the market for a longer driveshaft. Look for a shop in your area for an "expert" opinion.

 

[squaredeal91]

Pull it off real quick to see how much is inside

 

[Bextreme04]

Is this a long bed with a two-piece driveshaft? For most driveshafts you would check with maximum suspension compression, disconnect the driveshaft from the rear axle and then bottom out the yoke in the transmission. Make a mark on the yoke where it rides on the seal at bottomed out. Then pull it out 1/2" to 1" and that is the correct position.

If this is a two piece shaft, you might have an issue with the center support that is allowing it to walk out.

 

[Turbo4whl]

Yes, the yoke should be further in the trans. So most of the trucks on this forum have had previous owners. The question is why is it not correct?

The picture in your avatar, is this the truck, lowered? When a truck is lowered the drive shaft is too long and adjustment is needed. Can be completed several ways.

Next, 1973 trucks would have a 12 bolt rear axle. Many more later trucks have a 10 bolt rear. The 12 bolt has a longer nose, would have a slightly shorter driveshaft. What rear is in your truck? Was the rear replaced?

Did the rear axle shift back in the springs? Is there broken main leaf? Are the rear springs worn out and flat, that will move the rear back.

Is the frame rusty, did it bend? That will make the drive shaft too short.

You need to look at everything in the rear suspension. If everything is good, the drive shaft is too short.

 

[bucket]

Pull it off real quick to see how much is inside

Agreed. Reason being, it could be an aftermarket yoke and they are available in different lengths.

But if it's a stock yoke, yeah, that shaft is too short.

 

[BRetty]

Thanks to all who replied so far. More info:

My truck is a '73 frame and VIN, but has the dashboard, engine and transmission from an '81 Suburban. It is lowered 4.5/6, with a rear axle flip, all courtesy of the PO.

The rear diff is a GM 12-bolt. The rear diff is noisy and probably needs a new ring and pinion set. It has a single driveshaft, that seems to be carbon fiber. I had the rear u-joint fail about a year into owning the truck.

I had my TH350c transmission rebuilt in January. I specifically asked about the yoke extention, and they said no big deal. Best case on level ground I am still seeing at least an inch of shaft there.

I've always been worried about the extention and angle of the trans/shaft/diff, but they are the right direction(s) even if the angle approaches 5 degrees. My gearhed buddy says I worry too much!

---------
So, if this is a problem, do I take it to a differential and rear end shop?

Thanks,
BRetty

 

[HotWheelsBurban]

Thanks to all who replied so far. More info:

My truck is a '73 frame and VIN, but has the dashboard, engine and transmission from an '81 Suburban. It is lowered 4.5/6, with a rear axle flip, all courtesy of the PO.

The rear diff is a GM 12-bolt. The rear diff is noisy and probably needs a new ring and pinion set. It has a single driveshaft, that seems to be carbon fiber. I had the rear u-joint fail about a year into owning the truck.

I had my TH350c transmission rebuilt in January. I specifically asked about the yoke extention, and they said no big deal. Best case on level ground I am still seeing at least an inch of shaft there.

I've always been worried about the extention and angle of the trans/shaft/diff, but they are the right direction(s) even if the angle approaches 5 degrees. My gearhed buddy says I worry too much!

---------
So, if this is a problem, do I take it to a differential and rear end shop?

Thanks,
BRetty

Does the driveshaft have a black cover on it? The newer trucks and especially Burbs have an aluminum driveshaft that has this carbon fiber looking cover; sometimes they have come off. Since your truck has been lowered, that may have changed the length the driveshaft needs to be. I have a friend who has a 400 Burb a year older than mine, who has a lift kit on his. He had this same issue, and fixed it with a longer driveshaft (custom made).

 

[Turbo4whl]

The PO installed that drive shaft, too short. But since it has not failed then you may be okay. The drive shaft yoke angle is very important. They both should be in the same plane.

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[ReefkoiC10]

You should only have about 5/8” or so sticking out for a lowered truck like that

 

[SquareRoot]

If that shaft is indeed Carbon, it probably cost more than the truck is worth. lol