NP241 TCase Interchange.

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jjester6000

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So as some of you may know, my venerable 1998 Chevrolet Suburban has blown up another 4L60E.

I was going up a bit of a grade when I heard a loud clanking noise, before loosing all gears.

These faliures all seem unrelated, since the first trans still shifted fine loosing reverse. Second one, apparently the torque converter failed killing the pump, and the third one (actually the same trans as the second, but "rebuilt) seems to have had some castoatrofic failure.

I am now faced with a dilemma on that to do. I technically do have a warrenty from the guy who rebuilt it, but that would mean that I'd have to take it out and ship it back to Colorado, and probably wait several months for a transmission that will probably blow up again.

Or do I do a manual swap?

Well, I think I'm leaning that direction.

I just got one question, will the NP241 in my Suburban currently bolt to the back of this '97 NV3500 I found on FB marketplace?

If not I may just try to find a 2wd Transmission/driveshaft. I don't want to spend too much money, and I'm willing to give up 4wd for a manual transmission.

Hell I would even be willing to swap in my spare Saginaw 3spd in the endeavor.
 

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jjester6000

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I got the trans out, so now I got to figure out what I'm going to do now.

As I said, I found a cheap 4wd NV3500 for sale, and I know that it should bolt right in the place of a 4L60E, but the thing I'm not quite sure about is the TCase. I've heard that it's a direct swap, but I've also heard about it requiring a different input shaft.

How hard would replacing the input shaft in the NP241 be?
 

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jjester6000

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So after counting the splines on the output shaft on my 4l60e, and asking the seller the spline count on the NV3500, we both came up with 27 splines.

I was elated, knowing that my Tcase would fit the back of this trans, until I noticed this.

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That won't bolt up.
 
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there is more than likely a transmission adpater for the np241/np208 for that transmission. i am looking into the same but with a th475. check the web on a nv4500 to np208/np241 adapter. splines are splines, the other issue you will run into is output shafts come in different lengths. you may need a longer output shaft to bolt to the np241 after adding the adapter.
 

geardaddy

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that trans is from an S10. 27 spline but it has a 5 bolt adaptor. it will only bolt up to a np231 or np233 t/case..
 
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