NP 261 Rebuild

[Raptordude]

Hello,

 

Yesterday I decided to install a pump rub kit on a relatives truck, an 07 Silverado 2500HD classic with the 6.0 & 4l80e. The transfer case is the NP 261. As I was working on it, I discovered the pump rub failure had already occurred, and the transfer case had been running with 0 fluid for an undetermined amount of time.

 

Surprisingly, the bearings are not totally roached, but I think it would be a good idea to replace them. I’ll need a rear case half as well, it was worn through in 3 places.

 

A quick search online revealed that there are tons of rebuild kits out there for these, I even saw one from Walmart which seemed odd.

 

What is a good name rebuild kit to go with that won’t break the bank?

 

Also, is it a good idea to put an entirely new pump in since it had been running with no fluid? And are any special tools required to do a full rebuild that I’m not aware of?

 

Thanks

 

 

Sent from my iPhone using Tapatalk

[davester]

First, make sure you buy/get the RIGHT parts/kit.  There are at least 3 (possibly 4) versions of the NP261 (NP261, NP261HD, NP261XHD, and possibly a NP261SXHD).  Most likely your truck has the NP261HD, but there should be a round tag on the rear half that you can clean off to see.

 

There's a good youtube video of a mechanic assembling one:

 

The input shaft and front output shaft use 2-piece seals, that are certainly easier to install properly with the right seal driver.  And it helps to have a good, small puller for the small pin bearings in the housing/shaft.

 

I would suggest just getting a used TC from a junkyard and put in new bearings/seals/pump rub kit, probably will be cheaper than buying a new rear half.

[Raptordude]

Thanks for the reply, I actually arrived at that conclusion before seeing your response. After tearing it down completely, I see that it would take a very extensive rebuild to straighten it out. My relatives decided to put a cheap junk yard unit in and trade the truck in.



Looks like I need the plain old NP 261. I’m surprised it doesn’t say HD, since it’s an “HD” truck


Sent from my iPhone using Tapatalk

[davester]

Yeah, that's weird.  I have an '06 2500HD/6.0/4l80e (used as a parts/donor truck to upgrade my '04 Sierra 3500 to 4wd), and that came with a 261HD.  Perhaps check the chain measurements, and perhaps input/output shaft spline counts, I believe they are different between the 261/261HD, as perhaps someone just swapped the case half without changing the tag?

 

Or perhaps it's really a 2500LD?

 

Google "np261 vs np261hd differences" and make sure of what you've got, as there are some different parts between them.

[Raptordude]

I will check it out and report back. My dad bought this truck brand new and sold it to my grandparents a few years ago, so I know the case was never swapped out. I also am 100% sure it is a 2500HD. The plot thickens


Sent from my iPhone using Tapatalk

[davester]

Well, I don't know if/how unusual that is, for a 261 to be in a 2500HD.  I just know the '06 2500HD I bought had a 261HD, as well as the junkyard 2500HD (don't recall the year) had a 261HD as well (I also botched a seal, ran it dry, and swapped it out).

[Raptordude]

So I found a 261 HD near me that looks in good shape. Will this work? I’m not sure what the differences are between the 261 & 261 HD


Sent from my iPhone using Tapatalk