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Discussion Starter · #1 · (Edited)
Here is some tech I thought I might share with you guys. Upon searching many hours on PBB myself and Cajun4x4 decided to tear apart his big bearing round pattern 205 to swap in some goodies.
The reason we are swapping the long 32 Spline input gear to a short 32 Spline input gear is due to the Long 4.5" stickout on the back of the TH400 we are mating this tcase to. The long input on a 205 is made for a 2.5" stickout on a TH400 Hence us buying a short 32 spline input from a racetrack 205 which uses a 4.5" stickout tranny a 4"ish adapter and a short input. Thanks to Grumpyold Fart's thread we realized we could just swap input gears and be on our merry way. While doing that we decided to upgrade the stock GM 30 spline front output with a 32 spline front output and changed all 3 seals. Here is our attempt at a tech article for your viewing pleasure.



first the twin stick shifters where removed




next the th400/6 bolt round adapter was removed



remove the rear output yoke using a 1-5/16 or 33mm socket




using a 9/16 or 14mm socket the rear bearing retainer is the next to come off




remove the rear output bearing



then the speedo gear

 

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Discussion Starter · #2 · (Edited)
then the inner bearing/speedo assembly can be removed using a 9/16 or 14mm socket




the rear output shaft simply pulls out



next the shift collar can be removed from the shift rail



next the front bearing retainer can be removed using a 8mm 12 point wrench




using a set of lock ring pliers remove the snap ring holding the input shaft/bearing assembly together, this allows the input to be removed from the back of the case and the front bearing to be removed





cleaning old gasket material off

 

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Discussion Starter · #3 ·
long 32 spline input along side short 32 spline input



now reassembly can begin, install new input through the back of the case



then install the bearing and snap ring





if upon removal of the rear output shaft the inner rollers happened to fall out now its time to reinstall them, using liberal amounts of grease stick the rollers inside of the shaft





put the shift collar back into place then tilt the case so that the collar will stay lined up, now put the rear output shaft back into place


 

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Discussion Starter · #4 · (Edited)
next apply RTV then reinstall the rear bearing/speedo assembly using a 9/16 or 14mm socket, speedo gear and rear output bearing




next change out the seal in the bearing retainer, apply more RTV then reinstall onto the case using a 9/16 or 14mm socket (National seal # 473468)




install rear output yoke of choice using 1-5/16 or 33mm socket



now replace seal in front input bearing retainer, apply RTV then reinstall using a 8mm 12 point wrench (National seal # 710928)




with the front input changed its now time to move on the addressing the front output... start by removing the rear passenger side access panel using a 9/16 or 14mm socket




remove front output flange using 1-1/8" socket

 

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Discussion Starter · #5 · (Edited)
then remove the front output bearing retainer using a 9/16 or 14mm socket




next remove the output shaft through the back of the case along with the shift collar and gears, the front bearing can also be removed from the front of the case at this time





now remove the snap ring holding the gear on the output shaft and remove the gear



30 spline output along side 32 spline output



there will be a small metal pin located in the side of the shaft, remove it along with the two rows of needle bearings separated by a washer, then reinstall washer and metal pin into/onto the new output shaft then use liberal amounts of grease to reapply the two rows of needle bearings



 

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Discussion Starter · #6 · (Edited)
reinstall the gear and snap ring onto the new shaft



now reinstall the front output gear, shift collar and front output shaft back into the case through the back of the case with the case tilted as so the pieces can more easily line up, at this time also install the cross washer and front bearing




install new seal into bearing retainer (National seal # 473468 with use of 32 spline shaft/yoke) apply RTV and reinstall the passenger side access panel and front output bearing retainer using a 9/16 or 14mm socket for both




reinstall the 32 spline front output yoke of your choice using a 1-1/8" socket and you have your self a fully functional 205 once again!


 

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Excellent write up! Great job taking clear pictures showing every step of the process. I could see by your first pic that your case has already been twinsticked. I have already done these mods myself, except I put in a 31 spline ford input for use with my doubler. I wrote the twinstick mod that is here: http://pirate4x4.com/forum/showthread.php?t=572617&highlight=cheap
 

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Discussion Starter · #9 ·
No problem guys. It is Cajun4x4's case and we are putting it behind a TH400 that is replacing a 4l60e from his Z-71. We decided to make this happen since there was not a real tech wirteup specifically on PBB for these applications. Im gald we got to contribute to the best site on the planet. This site helped us so we wanted to help back.
 

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Discussion Starter · #11 ·
Cool write up, but I have one question. Why does your 205 have metric fasteners. Aren't they all SAE?:confused:
Almost every Gm Product I have used was metric fasteners. Maybe the older oned were SAE, but this case is a late 80's/ early 90's case and used metric fasteners.
 

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Daanngg Der Tboy. Dem dar coonazzes knows some stuffs bout dem dar tcases and stuff.

All b.s. aside, Guys, y'all did a great job. Excellent write up.
 

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The majority of the bolts on a NP205 require a 9/16 socket or wrench, a 14mm happens to work also. The bolts are 3/8-16 NC grade 5, look at the marks on the head, they are not metric.
 

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Discussion Starter · #15 ·
The majority of the bolts on a NP205 require a 9/16 socket or wrench, a 14mm happens to work also. The bolts are 3/8-16 NC grade 5, look at the marks on the head, they are not metric.
Good to know.
9/16 = 0.5625
14MM = 0.5511

The 14 MM fit well and was not too tight.
 

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My buddy has a 205 from behind a 465 which is 10 spline, the internals of a ford 205, and a 87 465 which he said should be 32 spline. He wants to build a 203/205 doubler, I will have to send him this thread. Excellent write up.
 

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33mm = 1 5/16

its not metric. its sae

I dont care what your sockets say. no NP205 ever had metric bolts unless someone retapped every fawkin hole.
 

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Discussion Starter · #20 ·
33mm = 1 5/16

its not metric. its sae

I dont care what your sockets say. no NP205 ever had metric bolts unless someone retapped every fawkin hole.
Thanks for the clarification. What we used worked, but your info is good to add thanks.
 
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