Rebuilding a Manual Transmission

[Dan96z71]

I have the NV3500 trans in my truck.

I was wondering if anyone knows how difficult it would be to rebuild it?

Second gear isn't doing so well.

Thanks for the help.

Dan

[RedHeartbeat]

you can buy a rebuilt center section for the transmission to swap out.

[hummertech]

if you havent ever done a trans rebuild on a manual before, this isnt the one to start on. i would do any other trans before this one. like red said if you get a remaned center sectioin the end cases swap over. (and thats not easy either.

this is just how to dissamble the mainshaft, this trans has 3 shafts and a shift interlock system that sucks.



Document ID# 703359


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Main Shaft Disassemble
Tools Required
• J 21427-A Speedometer Gear Puller Adapter

• J 22912-01 Split Plate Bearing Puller

• J 24420-C Harmonic Balancer Puller






If RWD vehicle, remove the main shaft bearing retainer.



Remove the following components from the mainshaft assembly:
• The 2 shift forks (1)

• The reverse idler gear (2)

• The countershaft rear bearing (4)

• The countershaft (3)





If RWD vehicle, using the J 21427-A (2) and the J 24420-C (1), remove the speed sensor reluctor wheel from the rear of the main shaft.
Do not reuse the reluctor wheel after removal.





If RWD vehicle, remove the mainshaft rear bearing retaining ring (1) and the mainshaft rear bearing (2).



Remove the mainshaft assembly from the input shaft.
Important: Leave the synchronizer ring on the 3rd/4th synchronizer assembly to prevent the synchronizer detent balls from popping out.

Remove the 4th gear synchronizer blocking ring and put on the 4th gear synchronizer assembly.
Remove the main shaft front bearing from the input shaft.



Remove the 3rd/4th gear synchronizer retaining ring.



Scribe an alignment mark on the synchronizer hub and the synchronizer sleeve in order to properly reassemble the synchronizer hub assembly.



Important: When removing the synchronizer hubs use the J 22912-01 under the gear for that synchronizer and not the synchronizer sleeve. Do not separate the synchronizer hub from the synchronizer sleeves. Leave the synchronizer rings with the synchronize assembly to prevent the synchronizer detent balls from popping out.

Using a hydraulic press and the J 22912-01 remove the 3rd/4th speed gear synchronizer hub assembly, the third speed gear and the synchronizer rings.
Remove the synchronizer assembly from the third gear.



Remove the 3rd speed gear needle bearing assembly (1).



Remove the following components:
13.1. The 2nd speed gear 2 piece thrust washer



13.2. The retainer ring





Remove the following components:
14.1. The 2nd speed gear (1)

14.2. The 2nd speed gear needle bearing assembly (2)





Remove the 1st/2nd gear synchronizer retaining ring from the main shaft.



Remove the following components for the 2nd gear synchronizer:
16.1. The synchronizer cone

16.2. The blocker ring

16.3. The reaction cone

16.4. The interim ring





Scribe an alignment mark on the synchronizer hub and the synchronizer sleeve in order to properly reassemble the synchronizer hub assembly.
Important: When removing the synchronizer hubs use the J 22912-01 under the gear for that synchronizer and not the synchronizer sleeve. Do not separate the synchronizer hub from the synchronizer sleeves. Leave the synchronizer rings with the synchronize assembly to prevent the synchronizer detent balls from popping out.

Using a hydraulic press and the J 22912-01 remove the 1st/2nd speed gear synchronizer hub and the 1st speed gear.



Remove the following components:
19.1. The synchronizer cone (5)

19.2. The blocker ring (4)

19.3. The reactor cone (3)

19.4. The synchronizer interim ring (2)

19.5. The 1st speed gear (1)





Remove the 1st speed gear needle bearing assembly.



Turn the mainshaft over to work on the output end.
Remove the following components:
22.1. The 5th speed gear (3)

22.2. The 5th speed gear needle bearing assembly (1). The needle bearing is split in order to remove it over the collar.





Remove the retaining ring for the 5th/Reverse synchronizer hub from the mainshaft.



Scribe an alignment mark on the synchronizer hub and the synchronizer sleeve in order to properly reassemble the synchronizer hub assembly.
Important: When removing the synchronizer hubs use the J 22912-01 under the gear for that synchronizer and not the synchronizer sleeve. Do not separate the synchronizer hub from the synchronizer sleeves. Leave the synchronizer rings with the synchronize assembly to prevent the synchronizer detent balls from popping out.

Using a hydraulic press and the J 22912-01 remove the 5th/Reverse speed gear synchronizer assembly and the reverse speed gear.





Remove the reverse speed gear needle bearing assembly (1).



Remove the reverse speed gear drag seal.

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Document ID# 703359

good luck on this one, it took 3 post just to tell you how to dissamble the mainshaft.

[RedHeartbeat]

That intimidates the hell out of me. I'd do a salvage unit or prefer a reman GM unit with warranty.

[Dan96z71]

way to scare someone!!! Just cuz it was halloween, does that mean that was a trick or treat?

Guess I will go with the reman unit.

I just wondered if there were any stronger parts that could be put into these. I hate to get a new one, and then blow that one up too.

[GMCwantsLS1]

Do you have the shifter/fork ass'y pictures? My tech has a problem with his NV3500 and any help would be great.

[hummertech]

NV3500 transmissions will brake shift forks if you speed shift them, there is no way arround it. get a NV4500 trans, it doesnt brake shift forks. (but it shifts like a school bus).

[GMCwantsLS1]

I think the forks are not broken just some springs poped out. The truck has 190K miles on a 4.3 and just started having problems.