NP241 driveshaft

[lowrodderchev]

I sent them pix of what I had and measurements he said he couldn't help me. I may just pull the trigger and order a few options and go from there

[lowrodderchev]

You were right First C10 guess I was over thinking it just ordered it thanx again.

[First c10]

What is the drive shaft off of?

[lowrodderchev]

87 Chevy 3/4 truck. Its the front one. I would gave rather got the 1/2 tin but I had no luck finding one. There was a auto wrecking in town but he wanted $260 each for used ones

[First c10]

I could be wrong but I think the front drive lines are the same in a 1/2 or 3/4 ton truck with Dana 44 front axles. If the truck the drive line came from had a Dana 60 front axle (like a heavy 3/4 ton or 1 ton) than it would be different. Of course I am not positive of it as my trucks have Dana 44's/GM 10 bolt front axles.

[lowrodderchev]

The saga continues lol found a driveline that would work got home put it on I measured wrong. So my slip yoke is little over 6 inches long I ended up with 3 1/4 in the transmission is that enough or am I back to the drawing board

[First c10]

I think you want about 1-1/4" to 1-1/2"space for the slip to go in or in your case with a 6" yoke it needs to be in contact with the tail shaft spline 4-1/2" to 4/3/4".
I may be a little off. I am sure someone else will chime in.
I will be needing a new front and rear drive line myself but I still need to measure it so I can find something hopefully without having to go custom.

[lowrodderchev]

Found out today my slip yoke has a crack in it

[lowrodderchev]

Well since I need a new slip yoke is it possible to pull this off my old 203 front driveshaft and add it to my rear?

[lowrodderchev]

Something like this

[lowrodderchev]

so drivelines finally in does this look right? or seems a little steep

[Zoomad75]

I'd measure it. Looks awful close to mine. Mine was off by at least 8 degrees. Get a magnetic protractor or a angle finder app on your phone and measure the angles.
Here's mine for comparison.

[lowrodderchev]

Originally Posted by Zoomad75

I'd measure it. Looks awful close to mine. Mine was off by at least 8 degrees. Get a magnetic protractor or a angle finder app on your phone and measure the angles.
Here's mine for comparison.

You happy with yours?

[Zoomad75]

Originally Posted by lowrodderchev

You happy with yours?

No. Despite some keen advice by Larry to get it sorted out before I put more miles on it, I took it out for a run to show it off and the rear shaft tried to escape the truck as I was driving it. This was the result..


Lucky for me I was slowing down from maybe 40 mph. Had this sucker let go when I was on the highway it would have beat the snot out of the floor and my nice new exhaust.

It happened as I was slowing down, which makes sense as the pinion angle dives under deceleration and that would have made the rear angle get that much worse. It spit one of the u-joint caps out and walked its way off the pinion yoke.

Moral to the story is measure the angles. Eyeball measurements don't cut it. The working angles need to offset each other. Like I said the amount my working angles are off by 8 degrees. I've got 8 degree shims to put between the rear leafs and axle. I'll probably drop the t-case/trans crossmember by at least 1/4" to help.

[lowrodderchev]

I seen that I went over your thread. I read so many I forget lol glad you weren't going fast. I'm new to measuring angles I'll have to read up on it. I did put a app on my phone for it. The front was 8 rear was 13

[lowrodderchev]

so if i am correct the transfer case and axle need to be parallel?

[First c10]

Originally Posted by lowrodderchev

so if i am correct the transfer case and axle need to be parallel?

In a perfect world, YES!

[Zoomad75]

Equal and opposing. But no more than 2 degrees off. This is why many with the same situation would go with the CV driveshaft. The double cardan (CV) joint will allow one to set the rear pinion angle to be equal to the driveshaft angle. The CV takes up the angles.

The problem I see compared to the 75 I parted out is the stupid slip yoke on the 241 is making the driveshaft up to 6 inches shorter than one with a fixed yoke The 205 case on my 75 was a fixed yoke. So the shorter the shaft the more the driveshaft angles effect it. It's one big compromise. The 241 has a better low gear ratio than the 205. The 241 is chain driven vs gear driven. The 241 is an aluminum case and the 205 is cast iron. SYE's on 241's are known to leak oil.

In my case we will add the DIY4x 8 degree shims and drop the t-case crossmember by 1/4 of an inch. Then we can remeasure. The funny thing is the Suburban Larry has was off by the same amount.

[lowrodderchev]

I'm going to try a 1 inch t case drop and see were it puts me hopefully it works out

[Zoomad75]

Originally Posted by lowrodderchev

I'm going to try a 1 inch t case drop and see were it puts me hopefully it works out

1 inch? Are you serious? I can't slide my fingers between the drivers side head and the firewall on mine, so the 1/4" I'm planning on going might require some massaging. Unless you've moved your engine forward a ton, the drivers side head will hit the firewall and limit your down movement.

Don't overlook the amount of stress you are putting on the t-case crossmember bolts if you shim it down that far.

Really your base measurements aren't as far off as mine were. You are missing the angle of the driveshaft. Measure it and take the pinion angle and the shaft angle, subtract the smaller from the larger and you have your rear working angle. Then take the t-case angle and shaft angle, again subtract the smaller from the larger and you'll have the front working angle. Compare the front working angle to the rear working angle and see where it sits. Shim the axle with wedges, recheck and move forward.

[lowrodderchev]

I had my motor far enough up were even after the 1 inch I still had finger room behind the motor. I'm now about 3 degrees off. If I shim my axle I'm afraid its going to pull the yoke out to much. Originally my yoke was 2 inches exposed it is now 1 5/8 exposed.

[lowrodderchev]

Came outside before work to check the angles again minus the drop. Pull the spacers came up with 7 degrees up front 19 in the middle and 10 at the rear. First time I measured it I used a app on my phone. Guess what the phone app sucks lol it told me way different numbers