NP 205 Rebuild and Info

[jbclassix]

I'm posting this here in hopes that it helps out others. I am hoping this can be a resource for the mighty New Process 205. I am rebuilding a vintage 1970 NP 205 for my Suburban. I would say this is a "first gen" 205, since my 69 has the Rockwell T221. If anyone has any info to add, please go right ahead. Also if anyone sees anything I did wrong, let me know and I will correct it so I am not spreading bad info. I don't have all the spline counts for all the different 205's so someone else will have to add that.

[jbclassix]

First I removed my rear output yoke. This is my home-made yoke holding fixture that has come in VERY handy over the years!



With the t-case in 4-hi I also removed the front yoke while holding the rear yoke.



Remove the speedo drive assembly



Remove the rear seal housing



The rear output bearing just slides off. It is "sandwiched between the yoke and speedo gear



Remove the speedo drive gear



Remove the spacer from behind the speedo gear



Remove the rear bearing housing. Be careful removing the housing, the front bearing is a needle type and they will fall out.

[jbclassix]

Next the Rear output shaft can be removed. There are roller bearings inside the output shaft assembly. They have a snap ring to keep them in place, but still use caution not to lose them.



Next I removed the front output seal housing



Next I pulled the front output bearing. There is a spacer/oil slinger behind the bearing.





Next I removed the rear bearing cover for the front output. There are more needle bearings so make sure you have all of them.





Next I pulled the front output shaft assembly. The shift collar and high gear stay in for now.



Next the shift collar and high gear come out. I reassembled the whole front output assembly to keep everything together.

[jbclassix]

The next part I had to dig for. To remove the shift forks, there are 2 expansion plugs on top of the case. Using a punch I drove them into the case. Under each plug, with the t-case in the neutral position, the roll pins for the forks can be driven out of the shift shafts.







Next I removed the shift bar, marking what direction it came off. I like these shift shafts. The ones on my 79 K5 had a longer 2-4 shaft with a boot-shaped shift bar.



More digging. There are two detent ball assemblies that need to come out.



The shafts can only come out if they are in the Neutral position because of the interlock pins. I put them back together so I could remember how they came out. This one is the Hi-N-Lo fork, the upper one.



This is the 2-4 fork. This is the lower one.



Next I removed the PTO plate. My case still had the original ID tag on it so it will go back on.





Next I removed the interlock pins. There is one in the front of the case and one in the rear of the case. I marked them so I would know where they came from.

[jbclassix]

Next I removed the snap ring that holds the input bearing on the input shaft. This one is the 27 spline type that mates to the TH350.



Next I removed the front bearing and pulled the input shaft out. I could not get the input shaft out without first removing the shift fork.

[jbclassix]

Next I removed the nut and washer on the front of the idler shaft.



Next I removed the idler shaft cover on the rear of the case. This is NOT what it should look like! The idler shaft lock-nut had come loose and the shaft had been spinning against the cover. This could have caused sever damage if it had not been cought.



A few taps with a soft face hammer sends the shaft out the back. Be very careful not to damage the threads!



The idler gear assembly will now drop down and out of the case. Be careful not to loose the bearings, spacer, and shims. Once again I put everything back together so I would remember how it goes back in.

[jbclassix]

Dirty, nasty, bare case



Clean and painted case. I only used a primer because it matched to original color that I could find on the inside and outside of the case

[Redcap]

This needs a sticky!

[jbclassix]

To begin re-assembly I started with the idler shaft. Here is a picture of how the rear bearing, spacer, and shims came off.



I assembled the idler gear cluster and front bearing to the shaft to check end play.



0.001"-0.002" is the spec I found for end play, and you are supposed to check it in a press. Well, I don't have a press. So this is how I loaded the bearings to check end play. I used a socket to press against the front bearing. After setting my shim pack I ended up with 0.002"



Here I laid the case face down and installed the gear cluster (bigger gear to the front) bearings, spacer, and shims. The idler shaft has to go through all of them so this was easiest.





Next I flipped the case and installed a new washer and nut. Torque is 150lbft. I also used lock-tight on the threads and marked the nut,shaft, and case to catch any movement. The front bearing gets torqued against the case, the rear of the shaft "floats in the bore and the shoulder torques against the rear bearing. If end play is not correct, the gear cluster will not rotate freely or there will be excessive end play after installation. I rechecked end play after torquing the shaft nut.





Next is the idler shaft cover with a new gasket. Note the orientation of the flat on the cover. Torque is 20lbft.

[jbclassix]

Next is the interlock pins



New shift shaft seals. The metal lips go out.



Next is the lower (2-4) shift fork assembly. Note that the longer side of the bore goes to the front of the case. The roll pin will be on the front of the fork. I learned the hard way this shift fork has to go in before the upper one because of the interlocks! Make sure your detent grooves are up. I started the roll pins in the forks for easier installation.





Next I installed the new input bearing with the outer snap ring.



Next I installed the input shaft into the bearing with the snap ring and a new O-ring on the input shaft. This O-ring seals the INSIDE of the coupler.





I installed the Hi-N-Lo shift fork assembly with the shift collar. This seemed to make it easy to keep the roll pin lined up with the hole in the case so it could be driven in.



Guys, I'm gonna call it a night for now on this post... I will continue on this tomorrow. I will proof read everything again and make sure I didn't miss anything. Tomorrow I will get into the frustrating parts! Hope you are enjoying what's here so far!

[y5mgisi]

Damn! Good job! I am positive i will use this as a guide in the future!

[jbclassix]

Thanks y5mgisi! Next I pulled apart the rear output assembly. This is the rear Low gear that is coming off the output shaft. First thing is pull the snap ring. You need a good large snap ring pliers on this one. Next is the index washer. Pay attention to that little pin sticking out of the shaft. The grove in the index washer needs to go over that.



Next pull the pin out of the shaft. This pin is real small and real important so don't loose it!



Next is the thrust washer. It has an indexing tab on it.



Next the low gear can be slid off. Have something that can catch all the rollers as they fall out. There is also a divider ring because there are two rows of rollers. the last thing to come off is another thrust bearing





This is the cleaned bare output shaft.



Next install the thrust washer with the index tab as shown



I used some cam assembly lube to stick the lower row or rollers to the output shaft. Next I set the divider ring on the shaft and then the Low gear. Make sure the gear is installed in the right direction. I then installed the top row of rollers.









Next install the thrust washer with the indexing tab as shown.



Now install that little retaining pin



Next is the indexing washer. the grove in the middle needs to sit over the pin and the groove on the perimeter needs to sit over the tab on the thrust washer. Next install the snap ring.



Now the shaft can be turned over. I used some cam lube again to hold the inner rollers in place. I used a screw driver to position them and a deep socket to ensure they were aligned to fit over the pilot in the input shaft.



Next is the retaining washer and snap ring. a socket worked good for seting the snap ring





Now the rear output can be installed on the back of the input shaft

[47thriftmaster]

jbclassix,
You just made my life a lot easier, as I'm just about to crack into my NP205 from my 72 Blazer. Great info and detail on here, awesome job. Quick question, were did you get your parts and seals? Keep it going the pics are great.

[jbclassix]

Originally Posted by 47thriftmaster

jbclassix,
You just made my life a lot easier, as I'm just about to crack into my NP205 from my 72 Blazer. Great info and detail on here, awesome job. Quick question, were did you get your parts and seals? Keep it going the pics are great.

eBay... they were pretty cheap

[jbclassix]

I am out of cam lube, so an old trick I am using this time is Petroleum Jelly to hold the rollers in place. Then with a new gasket I installed the rear bearing housing. Since none of the bolt holes are blind on the 205 I used thread sealant on ALL the bolts. Torque for the housing bolts are 30lbft





Next install the spacer, speedometer drive gear and rear bearing with a perimeter snap ring. You should be able to look down the speedometer adapeter hole and see the gear. Here you will also notice that the gear spins freely on the shaft. Once the yoke is installed and torqued, the gear, and spacer will be captured between the bearing and the shoulder on the shaft. This will also locate the output shaft to the rear which is why there is no thrust bearing between the input shaft and the output shaft











Next I installed the rear output seal in the seal housing. My rebuild kit came with several seals so I sized mine to the output yoke. It didn't take much force to set the seal at all. I am holding the housing in the orientation it goes on the case. You will notice the oil passage by my pinky finger. This has to line up with the hole on the case and cannot be covered by the gasket. The bolt holes are spaced differently so it's hard to get it wrong. Torque on these bolts is 30 lbft. Again use sealant on the threads. I did not find any specs on depth of the seal so I installed it flush.





I'm showing this picture without the seal housing for reference. At this point you should be able to pull the shaft back against the bearing

[jbclassix]

Rebuilding the front output is next



To make things easy, I removed High gear and the shift collar, cleaned them, and installed them in the case.









Next the front output comes apart very much like the rear output. Snap ring comes off, index washer comes off, pin comes out, and Low gear drops off the shaft. There were not thrust washers on the front output.





Once everything was clean I started putting it back together. I used Petroleum Jelly on the rollers to stick them to the shaft



For no reason, this time I set Low gear on the shaft, then installed the divider ring, then the second row of rollers.







Next the pin, then the indexing washer, then the snap ring







Next I installed the front output shaft in the case, feeding it through the shift collar and the High gear







Next I installed the thrust/slinger washer and the bearing with a perimeter snap ring. Sorry I forgot to take a picture of the bearing



For the front seal retainer my thumb is pointing to the oil passage that needs to line up with the notch in the gasket and the hole in the t-case. Here is the part I am not sure I did 100% right. The front seal has dual lips and the metal side is supposed to go on the inside. Well, both sides are metal, and there is a spring on both sides, so this is the way I installed it. Anyone wanna ensure this is correct?





I installed the seal housing with a new gasket, installed the bolts with sealant on the threads, and torqued the to 35lbft... I don't know why these are higher.



Next I used Petroleum Jelly to install the rear rollers



Then I installed the rear cover with a new gasket and sealant on the bolt threads. Torque is 30lbft

[jbclassix]

Next I installed the detent balls with the shift rails in Neutral, then the springs and then the caps. I don't have a torque spec for these







Then I installed the expansion plugs with a little sealant on them.



Next I installed the shift bar. Notice that on this type of linkage, the slotted hole goes to the 2-4 rail, and the holes are to the rear



Next I installed the linkage



Then the PTO cover with gasket and bolts. I don't have a torque spec, but the threads do need sealant



Then the speedo drive shaft and adapter. I don't have a torque for this

[jbclassix]

I am stopped here for a bit, this is a picture of my rear output yoke. I am going to try to clean off the teeth marks and speedi-sleeve it. This would be why I had a bad leak at the rear output.



If all your yokes are good to go, The torque spec that I found is 150lbft for rear. The front of this case is 10 spine. I don't have a torque spec. 30 and 32 spline front output torque is 150lbft. I will be using new nuts on both and speedi-sleeves on both. Once I have the sleeves I will cover the repair here.

[jbclassix]

There are 2 types of adapters for the TH350/NP205. This is the one I will be rebuilding. I may use a 700R-4, but I will not be re-using the TH350. Remove the inside snap ring and then the collar and bearing will come out as an assembly.





My bearing doesn't look to good and I don't have a new one, so this is where I am going to stop for now.

[y5mgisi]

Again, Great work and documentation! I really appreciate you taking the time to show us all of this! Thank you! As a silly question, Do you plan on painting the parts of the case that are now bare metal and left exposed?

[67chevy2wd]

Awesome job on the right up. Thanks, I just ordered my seal kit, can't wait to put this to good use

[jbclassix]

Originally Posted by Redcap

This needs a sticky!

How do you do that?

Originally Posted by y5mgisi

Again, Great work and documentation! I really appreciate you taking the time to show us all of this! Thank you! As a silly question, Do you plan on painting the parts of the case that are now bare metal and left exposed?

Glad I could help! on the paint, maybe... it may end up getting a coat of black on all but the aluminum, depends on what I decide once its in the frame. For now it's just coated in oil to prevent rust.

Originally Posted by 67chevy2wd

Awesome job on the right up. Thanks, I just ordered my seal kit, can't wait to put this to good use

Glad this will be useful!

[Booya]

Thanks for taking the time to post this. It will be very helpfull for my up comming rebuild... Bill

[47thriftmaster]

This is great, will definitely use your work in this thread as I do my NP205. Was the primer rustolium red primer? Do you plan to put a clear over the primer to seal it? That was my train of thought as I was wondering about paint.

[jbclassix]

Originally Posted by 47thriftmaster

This is great, will definitely use your work in this thread as I do my NP205. Was the primer rustolium red primer? Do you plan to put a clear over the primer to seal it? That was my train of thought as I was wondering about paint.

Yeah, the primer was just rustolium red... a matte clear would be a good idea for sure! I may do that!