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Thinking of doing a home made SYE for a np241

Fred_M1010

Fred_M1010

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Damn, this thread seems to be one of those deleted in the database crash:frown1:

There were some replys that I didn't have the time to read before they vanished, so if you could re-post them it would be great:thumb:

I think I recall my last question was about how a fixed yoke from a pinion would fit the output axle on the 241...?

I would cut the axle down in length and either make a threaded hole in the end of it for a bolt, or turn an "outside threaded part" and use a regular pinion nut.

The 241 output axle is 32-spline and 35mm (~1 3/8") in diameter all the way.
But I suspect pinions are slightly tapered...?

And second question is about hardening the material...
Does the axle need to be re-hardened afterwards?
 
The cheap easy method for a DIY SYE is to drill and tap the output shaft and use a TRUCK or VETTE TH400 bolt on Yoke and then put a slip in your driveshaft.
 
Ok, so an axle yoke won't fit then.
Are you sure it will be a tight fit?
No difference in diameter for the output axles between a 2wd th400 and np241?
 
COCHEV said:
Could you do the same thing to a 208?
Click to expand...

Yes. Like they are doing here: http://www.driveshaftsuperstore.com/SYE%20YOKES%20AND%20FLANGES%20ONLY.htm

But you don't get the other advantages of fixed yoke like longer driveshaft, reduced angles and less leverage on the output bushing/seal/tailshaft. But you still get to buy a new driveshaft!:rolleyes:

The TH400 yoke is the way around buying one of those (like 4x4High mentioned above). They were available in 32-spline, but sometimes the splines shape is a little *different*. You can also cut the longer TH400 yoke down to use as a standard fixed yoke, but it must be machined right.
 
Thanks Scott!
I went to my parts store today, and they had a TH400 yoke on the shelf :laugh:
It's for a 1350 U-joint but not with U-bolts unfortunately.

Here it is beside an old np241 output shaft from my 2500:

388201185029P02b3.jpg


I realize now that these are completely different than the ones on the pinions.
And they are not supposed to have that tight fit i was rambling about:doah:
I'll just have to cut down the shaft so the yoke bottoms out against the bearing when I bolt it down.

Does anyone know what size the bolt for the yoke should be?
Since I'm gonna tap a new hole I could use pretty much want size I want, but I would like to know whats stock for reference.

And next question would be what drive shaft to use for material?
My parts guy claimed there didn't exist a stock telescopic rear shaft...:confused:

But surely the ones behind a fixed yoke NP203 or NP205 must have been telescopic, right?
 
Is that Yoke a bolt on style? If not it won't work for you. Take a pic looking directly at the Yoke from the U-joint end.
 
That doesn't appear to be the correct Yoke. Going from my memory the Yoke will not have a large through hole in the end but rather a solid end with a small hole for the bolt.
 
4X4HIGH said:
That doesn't appear to be the correct Yoke. Going from my memory the Yoke will not have a large through hole in the end but rather a solid end with a small hole for the bolt.
Click to expand...


you get major kudos for that reply, i would have been the biggest smart ass about it bc obviously theres no where for a bolt to go. hi-jack off
 
4X4HIGH said:
That doesn't appear to be the correct Yoke. Going from my memory the Yoke will not have a large through hole in the end but rather a solid end with a small hole for the bolt.
Click to expand...

Isn't that the definition of a bolt-on yoke? The output shaft would have large threads - just like a pinion yoke or any factory T-case fixed yoke. The yokes that are closed on the end are slip yokes. Then you drill a hole for the small bolt. I think the ones that come prepped like that are aftermarket. I don't see why the one he has won't work - if he can just find the right washer.

What I question is whether the slip-style and bolt-on style have different spline dimensions - obviously a tighter fit is better for this conversion.
 
I just went out to the garage and looked at the TH400 bolt on Yoke I have had laying around and it is the same as the one pictured. Guess my memory isn't what it once used to be. :doah:
 
4X4HIGH said:
I just went out to the garage and looked at the TH400 bolt on Yoke I have had laying around and it is the same as the one pictured. Guess my memory isn't what it once used to be. :doah:
Click to expand...

The joys of age! Of all the things I've lost over the years, I miss my memory the second most.

I forgot what the first was L:doah:L

-- A
 
Ok, that's a relief.

Any ideas on what drive-shaft to use for the "slip part" on the drive-shaft?
Would a front d-shaft be strong enough?

And any ideas on what dimension and grade on the stock bolt for the yoke?

I've also been thinking some on how much to cut down the output shaft...
I could cut it so that the yoke bottoms out against the bearing,
that would give me ~2 1/2" of spline contact between the shaft and the yoke.
Or I could cut down the yoke some as well, and cut the shaft even more...
That would give me less spline contact, but a shorter installation...:thinking:
Or if I would want maximum spline contact (which I don't think I need) I could make a spacer between the yoke and the bearing, but that makes for a really long installation...

Here's the pic of the yoke and shaft again for reference:
(To bad tha output shaft doesn't have splines all the way to the bearing surface)
388201185029P02b3.jpg




iwaxmyjimmy said:
you get major kudos for that reply, i would have been the biggest smart ass about it bc obviously theres no where for a bolt to go. hi-jack off
Click to expand...

Yeah, major kudos :surepal: :flipoff13: ;)
 
Is the yoke splined all the way through? If so it seems plenty long to bring the end of it back past the splines. You can only get so short with a yoke that long anyway...
 
Wait- here is an important question. When the yoke bolts on, what will it be bottoming out against? The right size spacer might let it hit only the rotating part of the output bearing, but is that OK? As in - what holds that bearing in place? Maybe you can machine a snap ring groove in the shaft just outside of that.

What kind of machine shop do you have access to? Any chance of cutting threads in the output shaft for a pinion nut? This would be superior to the Tom Woods kit.
 
The yoke is splined almost all the way through.
It's just about 0.3" at the inner end thats free of spline, just enough so that it can slip over the surface where the bearing sits, and press directly at the bearing.

I'm pretty sure it only hits the inner race of the bearing, but if it doesn't,
it could be fixed with a spacer as you say.

Thanks for the heads up on the bearing btw.
I believe it's ok to press against it, but I will check it out more closely when I disassemble the case.
 
I've bought two different wrong version np241, one 32-splined but with an electric VSS, and one 27-splined with a mech. VSS.
So I'm going to swap parts between them to get one 32-splined with a mech VSS...

For drive shaft, I've realized that the front shaft from an IFS-truck might work (as long as it doesn't have an auto-trac TC).
They have single 1350 joints in both ends, and slip in between...
But since it'll be longer, I'm not really sure it'll be strong enough...

But it don't have much time for working on it now, so it'll probably take some time before I'll finish it
 
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