AMC Eagle Den Forum

The Shop => 4X4 and Driveline => Topic started by: eaglefreek on June 15, 2011, 09:56:45 PM

Title: Reclocking NP229 Tail housing
Post by: eaglefreek on June 15, 2011, 09:56:45 PM
I put together a few photos to show what needs to be done to reclock the tail shaft housing on a NP229 transfer case so that the speedometer cable enters the case in the same spot as it does on a 119/129/128 transfer case.
The only Eagle case I have taken apart is my 128. I was originally going to use the back have of the 128 case on the front half of the 229 case so the tail shaft housing would bolt up. It's hard to explain but there is one rail inside the 128 for the 2wd/4wd selector. In the 229 there are two rails. One for 2wd/4wd and one for the low range. I've read you can put the Eagles back case on the 229 however the hole in my 128 case, where the low range rail would need to fit, was too small and would have been too difficult to enlarge.
Here's a pic of a 229 on top and 128 on the bottom.
(http://img.photobucket.com/albums/v637/svoman2300/IMG_0717.jpg)
The red circles are where the speedometer cable enters the transfer case. I didn't try it but I've read that if the 229 TC is installed as is, there will be problems with the cable hitting the floor. The tail shaft housings themselves are identical between the Eagles TC's to the 229. The only difference is where the vent is installed from the factory. You can see the 229 vent circled in yellow and where it would be on an Eagle TC in purple. I don't think it would make a big difference if a 229 housing was installed without moving the vent to the Eagle's location but it would be fairly easy to move.
229
(http://img.photobucket.com/albums/v637/svoman2300/IMG_0719.jpg)
128
(http://img.photobucket.com/albums/v637/svoman2300/IMG_0718.jpg)

Here's a pic of the 128 with the tail shaft housing removed.
(http://img.photobucket.com/albums/v637/svoman2300/IMG_0720.jpg)
Circled in red is where the bolts for the tail shaft housing thread into for the Eagle location. The yellow circles are just holes, no threads. That is where the 229 case holes would be. Notice one hole is missing by the arrow. On both of the 229 cases I have, they only had one set of holes where you see the yellow circles. I drilled new holes where the red circles are and then tapped them. There is a boss for the holes. I split the case to keep shards from getting into the TC. Actually you could try to tape off the holes that would let shavings into the case and not drill deep enough to go through the boss. It would require a bottom tap since you will be tapping a blind hole. It is important to get the holes in the right spot. If you don't feel confident, it would be quite easy for a competent machinist.
Here's a couple of pics of the vent on the housing. This is the 229 location. If you had to use the 229 housing you could plug the one hole and drill a new hole in the proper location.
(http://img.photobucket.com/albums/v637/svoman2300/IMG_0722.jpg)
(http://img.photobucket.com/albums/v637/svoman2300/IMG_0721.jpg)
It sounds difficult, but once you have it in front of you, it will make sense. The 229 swap is not a bolt in and go. It does require some minor fab work to be done CORRECTLY. Anyone can slap stuff together, but if you want something to work correctly, without trouble, it is better to spend a little more time to do it right. Hope this makes sense.
Title: Re: Reclocking NP229 Tail housing
Post by: Draekon on June 15, 2011, 11:17:13 PM
Great write up.  Egg to you
Title: Re: Reclocking NP229 Tail housing
Post by: vangremlin on June 15, 2011, 11:43:53 PM
Thanks for the write-up!!

Did I read somewhere that there is an adaptor available (90 degree) that will work with the speedometer cable so you can avoid having to re-clock it?  Maybe this one here? Thanks.

http://www.transmissioncenter.net/speedometer_calibration_______va.htm#90 Degree
Title: Re: Reclocking NP229 Tail housing
Post by: Whuntmore on June 15, 2011, 11:51:00 PM
That is awesome, and thanks for the info  Eggs to you!
Title: Re: Reclocking NP229 Tail housing
Post by: carnuck on November 12, 2013, 12:12:02 AM
I moved mine someplace in my collection. Would be nice to tell how fast I was going!
Title: Re: Reclocking NP229 Tail housing
Post by: fischrman on May 23, 2014, 10:19:39 PM
Hey, im doing the swap right now also. I reached the point wear the second rail isn't fitting..   can you not just drill that out on the inside of the new casing? I keep searching the info and I cant seem to find anything on it..
Title: Re: Reclocking NP229 Tail housing
Post by: DaemonForce on May 24, 2014, 12:52:20 AM
This data will become useful to me soon seeing how I'm about to go into DAY 3 of recovering a NP229 from an 85 XJ. I seem to have a very serious problem when recovering stuff from Jeeps and it shows. Everything is so rotted and locked together that major drivetrain components are completely seized. I'll have to return to Lakewood in the morning with a punch and hammer just to separate the back end of the transmission from the 4WD. x_x

This was quite sight even though the center dash had been pulled apart. The passenger and back seats looks great though it's the tacky blue tone throughout the Jeep. What originally caught my attention to look underneath was the bizarre floor centered on the fly style vacuum shifter just sitting between the front seats. Weirdy. I only thought these existed in the 84-86 Grand Wagoneer and none of the picking yards are getting those anymore. So this was a shock.

(http://i.imgur.com/5afbwd7.jpg)

Luckily a legendary NP229 sits underneath this mess but I had heck trying to get the shifter loose and all the other sludged up garbage that was in the way. Even the front driveline was a pain(and pressurized). I seem to be missing my 13mm wrench lately but I've been able to manage with a traditional 9/16" in its place. Forget the write up about modding the NP229. Why is it so horrifying to acquire this 4WD unit in the first place? Even the rebuild kits are impossible to find.
Title: Re: Reclocking NP229 Tail housing
Post by: The Dark Side of Will on May 26, 2014, 04:15:16 PM
Quote from: fischrman on May 23, 2014, 10:19:39 PM
Hey, im doing the swap right now also. I reached the point wear the second rail isn't fitting..   can you not just drill that out on the inside of the new casing? I keep searching the info and I cant seem to find anything on it..

The cored hole in the case is not in the correct location. It has to be done on a mill because the final machined hole is a little bit off from the cored hole.
Title: Re: Reclocking NP229 Tail housing
Post by: carnuck on May 29, 2014, 07:54:13 PM
The tailstock of the trans is held in place by a snap ring under the trans mount. There is a plate with 2 screws that come out, then you squeeze or spread the snap ring to separate it from the output shaft bearing. #897 on this diagram. It's basically the same picture for 727 or 9XX trans
http://www.makcotransmissionparts.com/mm5/graphics/Catalog-pdf/A727.pdf