Technical Service Information Bulletin
Date: January 17, 2024
Bulletin Name: FDM-TSIB-044
Model: Oshkosh S-Series 2.0

2.0 TRW Primary Steering Gear
Sector Shaft Lash Adjustment
Purpose:

This bulletin provides instruction for adjusting the primary steering gear on vehicles exhibiting an undesirable
amount of steering input needed to achieve a desired steering output. Adjustment of the steering gear sector shaft
lash is a normal maintenance task.

Notice:
• Read and understood bulletin in its entirety before performing this procedure.
• View steering gear supplier general sector shaft adjustment procedure video.

• All procedures outlined in the bulletin must be performed by skilled service personnel. Refer to the product
service manual for descriptions of maintenance procedures.

SAFETY NOTICE

Perform your company’s Lockout/Tagout
procedure. If your company does not have a
Lockout/Tagout procedure, follow OSHA
1910.147 and 1910.146 Confined Space as
appropriate.

SAFETY NOTICE

Use appropriate Personal Protective
Equipment (PPE) as required by your
company.

Tools and Equipment Required:
Customer to supply:
• Flat blade screwdriver
• 3/4 inch wrench (regular and thin)
• 1/2”-20 nut
• 1/2”-20 thread chaser
• Primer and paint
• Torque wrench (foot pound)

Procedure:
Lockout/Tagout
1. Park vehicle on a flat level surface with the front wheels straight, block truck tires, and perform your
company’s Lockout/Tagout procedure. If your company does not have a Lockout/Tagout procedure, follow OSHA
1910.147 and 1910.146 Confined Space as appropriate.
2. The vehicle’s BATTERY DISCONNECT switch is located on the left-hand side of the battery box. Use the
battery disconnect switch when performing any maintenance so the vehicle cannot accidentally be started.
a. Turn the battery disconnect switch (Figure A, Item 1) counterclockwise so the hole on the switch aligns
with the hole in the bracket (Figure A, Item 2).

1

b. Install the safety lockout device ring (Figure B, Item 1) through the holes on the battery disconnect switch
and the bracket.
c. Install a padlock (Figure B, Item 2) onto the safety lockout device ring, lock it, and put the key in your
pocket. If more than one person is working on the vehicle, each person must install his or her own padlock.

1

DA
NG
ER

Th
be is en
e
e
n
LO rgy
Un
CK sou
th auth
ED rce
OU ha
in is loc oriz
T! s
R im k/t ed
e
ma media ag m rem
rks te ay ova
:
dis re l o
ch sult f
arg
e.

1

2

2

Figure A

Figure B

Sector Shaft Lash Adjustment
3. Make sure front wheels are pointed straight ahead. See Figure 1.

Figure 1 - Front Wheels Straight

4. Locate primary steering gear behind front bumper from below front of vehicle. See Figure 2.

Primary Steering Gear

Front Bumper

Figure 2 - Primary Steering Gear Location

2

5. Locate side cover sector shaft jam nut and adjustment screw. See Figure 3.

Side Cover
Jam Nut
Adjustment Screw

Figure 3 - Lock Nut and Adjustment Screw Location

CAUTION

Always wear safety glasses and appropriate
personal protective equipment (PPE) when
using wire wheels. A face shield must be
worn when using wire wheel. Failure to
comply could in personal injury to
unprotected eyes and/or skin from flying
debris.

CAUTION

Use caution when removing paint from jam
nut and adjustment screw not to damage any
hydraulic lines or wire harnesses. Failure to
comply could result in damage to equipment.
6. Loosen and remove side cover jam nut from adjustment screw. Use a right-angle die grinder with wire wheel
to clean paint off threads prior to removing jam nut. See Figure 4. If threads are clean enough, screw can be
held stationary while removing jam nut. See Figure 5.
The jam nut can be removed without first cleaning threads, but sector shaft adjustment screw will likely back out
entirely until it bottoms out on the side cover.

Figure 4 - Right-Angle Die Grinder

3

Figure 5 - Jam Nut Removal

7. Clean off any remaining paint on the adjustment screw or jam nut. Use a 1/2”-20 thread chaser to fully clean
threads on adjustment screw. Paint must be completely removed from side cover jam nut and adjustment screw
to allow full movement of adjustment screw.
8. Tighten the adjustment screw to fully seat the sector shaft gears using one of the following procedures.
Preferred Procedure:
a. Reinstall side cover jam nut onto adjustment screw leaving enough threads to install a second 1/2”-20 jam
nut behind the side cover jam nut. Tighten the two nuts against each other. See Figure 6.
b. Using the two locked nuts, tighten the adjustment screw until it bottoms out, ensuring that the jam nut is
not contacting the cover. If jam nut is contacting the cover, loosen the jam nuts and back nuts slightly further
off the adjustment screw prior to re-tightening against each other.
c. Proceed with torquing the assembly to approximately 55 ft lbs.
d. Using a thin 3/4” wrench, unlock the two jam nuts by tightening the side cover jam nut while holding the
second jam nut with a second 3/4” wrench. Remove the second jam nut.
e. Torque the side cover jam nut to 42 ft lbs.

Sector Shaft

Side Cover
Jam Nut
Second Jam Nut
(customer supplied)

Adjustment Screw
Figure 6 - Jam Nuts

4

Alternate Procedure:
a. If an inadequate amount of threads are available to fit both nuts and avoid contact with the side cover
while torquing, remove second jam nut and proceed by using a flat blade screwdriver to tighten adjustment
screw as much as possible with the screwdriver. See Figure 7.
b. Torque the side cover jam nut to 42 ft lbs. See Figure 8.

Flat Blade Screwdriver

Figure 7 - Tightening Adjustment Screw

Flat Blade Screwdriver
3/4 Inch Wrench

Figure 8 - Tightening Jam Nut

9. Remove lockout/tag and wheel chocks.
10.
Test drive vehicle and verify sector shaft lash adjustment. If vehicle performance is not improved, repeat
adjustment procedure and tighten adjustment screw more than the previous adjustment.
11.
If vehicle performance is not improved after multiple adjustments, contact a McNeilus National Service
Representative at 888-686-7278.
12.
After adjustment clean adjustment screw/side cover jam nut area of steering gear and apply a coating of
paint if desired.

Continuous Improvement:

The change included in this document is part of the
McNeilus Continuous Improvement Process.
McNeilus’s quality policy is providing customer satisfaction
through innovative products, dedicated service, and a
constant focus on continuous improvement.
5

(888) 686-7278
www.streetsmartparts.com