SPL250 Lite HT / SPL350 Lite HT
Driveline Vibration Diagnostic Procedure
1. Complete the OEM vibration diagnostic procedure to identify the suspected root cause
of the vibration complaint.
2. If the drivelines have been identified as the root cause of the complaint, remove the
rear driveshaft from the main driveline by disconnecting it from the half round end yoke
at the rear axle input. Support the driveshaft with a lift or floor jack and pull the
driveshaft out of the coupling shaft. Note that the plastic boot over the slip member
will separate from the midship shaft and remain attached to the rear driveshaft. Do not
remove the boot clamp or boot from the rear driveshaft.
3. With the rear driveshaft removed, run the powertrain in the gear and at the engine rpm
that produces the vibration complaint from the road test.
4. If the vibration is eliminated, the root cause is the main driveline. Proceed to step 10.
5. If the vibration is still present, remove the midship shaft from the truck by disconnecting
it from the half round end yoke at the transmission by removing the half round bolt and
caps and remove the hanger bolts at the center bearing.
6. With the midship shaft removed, run the engine / transmission in the gear and at the
engine rpm that produces the vibration complaint from the road test.
7. If the vibration is still present, the root cause of the issue is in the engine, flywheel,
clutch, or transmission. Follow your OEM warranty process to determine the root cause
and correct the issue.
8. If the vibration has been eliminated, inspect the transmission end yoke nibs for damage.
If damage is found replace the transmission end yoke, re‐install the midship shaft, and
re‐test.
9. If no damage is found in the transmission end yoke or if the vibration persists with the
new transmission end yoke, the root cause is in the main driveline.
10. The main driveline has been confirmed to be the root cause of the vibration. The truck
can be repaired by one of the following methods:
a. Order replacement drivelines through the OEM warranty process. Note that the
Lite Series drivelines are manufactured as a matched pair and must be replace as
a set (both driveshaft and coupling shaft).
b. Have the drivelines (main and coupling shafts) repaired and re‐balanced at a
reputable driveshaft shop. Refer to the “SPL250 Lite HT / SPL350 Lite HT
Driveline Re‐work Instructions” for the proper repair procedure.
11. Refer to the “SPL Lite Installation Instructions” document for proper installation of the
drivelines.

SPL250 Lite HT / SPL350 Lite HT
Installation Instructions
Midship Shaft Installation:
1. Install coupling shafts into the vehicle using the same procedure currently used on standard SPL
products.
2. Remove the shipping cover from the splined sleeve at the midship bearing end.

3. Locate the yellow paint stripe on the outer surface of the splined sleeve. This indicates the
location of the missing tooth in the female slip spline. If the yellow line is smeared or not visible,
locate the missing tooth inside the splined sleeve and re‐mark the location on the outer surface
of the sleeve. Note: There are two missing teeth 180 degrees apart and either one can be used.

4. Rotate the coupling shaft so that the yellow line is visible during installation of the rear
driveshaft.

Driveshaft Installation:
5. Remove the shipping cover from the male slip spline on the rear driveshaft by pushing inward
on the boot to slide it off the cover and then pull outward on the spline cover.

6. Locate the yellow paint mark in the root of the spline teeth. This line indicates the location of
the blind spline for orientation. This mark is located 90 degrees from the centerline of the yoke
lug ears. If the yellow paint is not visible the location of the blind spline can be identified by the
punch mark on the end of the spline root.

7.

Support the rear driveshaft under the truck with a lift or jack.

8. Align the yellow line in the male spline with the yellow line on the splined sleeve on the coupling
shaft and insert the male slip spline into the female splined sleeve. If the splines are not properly
aligned, you will not be able to assemble the driveshaft into the coupling shaft. Do not force
assembly, it will damage the coating on the internal splines.

9. Using steady even pressure slide the driveshaft splines into the coupling shaft until it bottoms
out. As the slip spline is installed the slip, the boot will slide over the splined sleeve and snap
into the grove next to the midship bearing assembly. Inspect the boot to ensure that it has
seated against the midship bearing slinger. No clamps or tools are needed to secure the boot.

10. Install the fixed end of the driveshaft into the half round end yoke at the axle using the same
procedure currently used on standard SPL products.

SPL250 Lite HT / SPL350 Lite HT
Driveline Repair Procedure
1. Mount the coupling shaft in balance fixturing and measure the run‐out of
the splined sleeve next to the tube weld. Place the dial indicator anvil on
the machined diameter of the splined sleeve as indicated on the diagram
below. If the indicator reading is 0.006 inches or less, proceed to step 4. If
the indicator reading exceeds 0.006 inches the coupling shaft must be
repaired.

2. Mark the tube and splined sleeve radial orientation to maintain the proper
shaft phasing. Cut the weld between the tube and splined sleeve and
reposition the splined sleeve to lower the runout of the splined sleeve next
to the weld as low as possible.
3. Inspect the phasing marks for alignment and re‐weld the splined sleeve.
After the weld has cooled verify that the run‐out is 0.003 inches or less. Do
not attempt to straighten the tube or tube yoke end by heating and
cooling the tube (flame straightening).
4. Assemble the coupling shaft and driveshaft as a two‐piece system in the
balancer and balance the system as low as possible. Do not attempt to
straighten or re‐work the rear driveshaft as it has been balanced
individually to a very low specification.