Disassemble NV3500 HM290 5 Speed Transmission

Disassemble NV3500 HM290 5 Speed Transmission

Disassemble NV3500 HM290 5 Speed Transmission

The following information is provided to assist you with disassembly teardown of your NV3500 HM290 5 speed manual transmission.  This transmission is used in both General Motors and Dodge vehicles.

1.  Remove idler shaft support bolt and 2 each bottom bolts holding rear housing to main case.  Remove the backup light switch and vehicle nv3500_da_fig3_th.jpg.jpg speed sensor assembly if your transmission has one.

2.  Remove detent plug, springs and balls from main case, see figure 3.  On rear housing remove 2 bolts on shift rail detent spring cover.  Remove cover, springs and balls, see Figure 4.

3.  Remove output shaft oil seal.  With transmission in vertical position, remove input shaft bearing retainer.  Remove snap ring and selective shim.  Position transmission horizontally and remove front housing to rear housing bolts.

4.  Drive dowels into front housing and remove front housing.   Remove countershaft bearing and bearing race.  Snap out idler shaft support.  Remove 4 rollers and roll pin.  Pull shifter rail forward.

5.  Support shift rail end while drive out shift finger roll pin.  Remove rail socket assembly roll pin,  See Figure 5.  Don't apply excessive force, or pin will peen shift rail and damage the rear housing shift rail bearing.

6.  Remove shift rail, shift rail socket assembly and finger.  Pry out 3rd-4th shift fork roll pin.  Remove 3rd-4th rail plug and rail.  Ensure 1st-2nd, and 5th reverse rails are in Netural position.  Drive rail though plug hole.

7.  Expose roll pin hole, and insert a 3/8" punch through roll pin hole.  Pull out shift rail.  Remove 2 detent balls.  See Figure 6.  

8.  On 2WD models, remove rear housing.  Remove otput shaft bearing retainer and bearing.  Slid snap ring away from speed sensor for clearance.  Remove speed sensor rotor, do not reuse rotor.

9.  Remove 2 snap rings and output shaft bearing assembly.  On 4WD models, remove rear housing assembly and bearing.  On all models, remove reverse idler gear assembly, counter shaft, 1st-2nd shift rail assembly, 5th reverse shift rail assembly and 3rd-4th shift fork.  Remove main shaft assembly, input shaft and pilot bearing.  Once you have finshed the inspection we can help you with master bearing overhaul kit, kits with syncro rings and other hard parts.  

  Click on image to enlarge.