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T850 MANUAL TRANSAXLE
TABLE OF CONTENTS
page page
T850 MANUAL TRANSAXLE
DESCRIPTION........................308
OPERATION..........................311
DIAGNOSIS AND TESTING - COMMON
PROBLEM CAUSES...................318
REMOVAL............................318
DISASSEMBLY........................323
ASSEMBLY...........................329
INSTALLATION........................338
SPECIFICATIONS - T850 MANUAL
TRANSAXLE........................343
SPECIAL TOOLS - T850 TRANSAXLE.......345
AXLE SEALS
REMOVAL............................348
INSTALLATION........................348
BACK-UP LAMP SWITCH
REMOVAL............................349
INSTALLATION........................349
DIFFERENTIAL
DESCRIPTION........................349
OPERATION..........................349
DISASSEMBLY........................350
ASSEMBLY...........................353
ADJUSTMENTS
ADJUSTMENT - DIFFERENTIAL TURNING
TORQUE...........................356
ADJUSTMENT - DIFFERENTIAL SIDE GEAR
ENDPLAY..........................358
FLUID
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK............................358
STANDARD PROCEDURE - FLUID DRAIN
AND FILL...........................359
GEARSHIFT BOOT
REMOVAL............................359
INSTALLATION........................360GEARSHIFT CABLE - CROSSOVER
REMOVAL............................360
INSTALLATION........................363
ADJUSTMENTS
ADJUSTMENT.......................366
GEARSHIFT CABLE - SELECTOR
REMOVAL............................368
INSTALLATION........................371
GEARSHIFT KNOB
REMOVAL............................374
INSTALLATION........................374
GEARSHIFT MECHANISM
REMOVAL............................375
INSTALLATION........................377
INPUT SHAFT
DESCRIPTION........................380
DISASSEMBLY........................380
ASSEMBLY...........................383
INTERMEDIATE SHAFT
DESCRIPTION........................387
DISASSEMBLY........................388
ASSEMBLY...........................395
SHIFT COVER
DESCRIPTION........................401
SHIFT FORK AND SHAFT
DESCRIPTION........................402
SYNCHRONIZER
DESCRIPTION........................402
DISASSEMBLY........................402
CLEANING
CLEAN............................402
INSPECTION
INSPECT...........................402
ASSEMBLY...........................403
VEHICLE SPEED SENSOR
REMOVAL............................403
INSTALLATION........................403
T850 MANUAL TRANSAXLE
DESCRIPTION
The NV T850 5-speed transaxle (Fig. 1) is a con-
stant-mesh manual transaxle that is synchronized in
all gear ranges, including reverse.
The transaxle consists of three major sub-assem-
blies: the input shaft, intermediate shaft, and differ-ential assembly. The transaxle shift system consists
of a mechanical shift cover, rails, forks, and cables.
The unique design of this shift system provides a
higher mechanical advantage, resulting in less fric-
tion and lower shift cable loads for smoother, more
positive operation.
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Fig. 1 NV T850 Transaxle
1 - 3RD GEAR (SPEED) 9 - INTERMEDIATE SHAFT BEARING
(SEALED BALL)17 - 1/2 SYNCHRONIZER
2 - 3/4 SYNCHRONIZER 10 - REVERSE GEAR 18 - 1ST GEAR (SPEED)
3 - 3/4 SHIFT FORK 11 - 5/R SYNCHRONIZER 19 - DIFFERENTIAL ASSEMBLY
4 - 4TH GEAR (SPEED) 12 - 5/R SHIFT FORK 20 - EXTENSION HOUSING
5 - 5TH GEAR (INPUT) 13 - 5TH GEAR (SPEED) 21 - INTERMEDIATE SHAFT BEARING
(CAGED ROLLER)
6 - REVERSE IDLER GEAR 14 - 3/4 CLUSTER GEAR 22 - INTERMEDIATE SHAFT
7 - END COVER, REAR 15 - 2ND GEAR (SPEED) 23 - INPUT SHAFT
8 - INPUT SHAFT BEARING (SEALED
BALL)16 - 1/2 SHIFT FORK 24 - CASE
25 - INPUT SHAFT BEARING (ROLLER)
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T850 MANUAL TRANSAXLE (Continued)
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The NV T850 transaxle is available with the 2.4L
Gas and 2.5L Turbo Diesel engine options. Unique
gearing tailored to the performance characteristics of
each engine provides optimum driveability, gradabil-
ity, and acceleration. The gear ratios are as follows:
GEARRATIO (2.4L
Gas)RATIO (2.5L
TD)
1st 3.65 3.46
2nd 2.07 2.05
3rd 1.39 1.37
4th 1.03 0.97
5th 0.83 0.76
Reverse 3.47 3.47
Final Drive
Ratio3.77 3.53
Overall Top
Gear3.12 2.66
TRANSAXLE IDENTIFICATION
NOTE: Since transaxles use unique gear ratios for
each of the two engine applications, it is imperative
that the transaxle is properly identified, and the cor-
rect transaxle assembly number is used when
ordering service parts.The transaxle model, assembly part number, build
date, and final drive ratio (FDR) can be found on a
metal tag fastened to the transaxle case on the bell-
housing (Fig. 2). A barcode label is also glued to the
transaxle bellhousing, and it too includes the trans-
axle part number.
Fig. 2 T850 Transaxle Identification
1 - TRANSAXLE BELLHOUSING
2 - BARCODE LABEL
3 - I.D. TAG
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T850 MANUAL TRANSAXLE (Continued)
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OPERATION
NEUTRAL
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. Since
no synchronizers are engaged on either the input or
intermediate shafts, power is not transmitted to the
intermediate shaft and the differential does not turn
(Fig. 3).
Fig. 3 Neutral Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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1ST GEAR
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. The
input shaft first gear is integral to the input shaft,
and is in constant mesh with the intermediate shaft
first speed gear. Because of this constant mesh, the
intermediate shaft first speed gear freewheels until
first gear is selected. As the gearshift lever is moved
to the first gear position, the 1-2 fork moves the 1-2
synchronizer sleeve towards first gear on the inter-
mediate shaft. The synchronizer sleeve engages the
first gear clutch teeth, fixing the gear to the interme-
diate shaft, and allowing power to transmit through
the intermediate shaft to the differential (Fig. 4).
Fig. 4 1st Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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2ND GEAR
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. The
input shaft second gear is integral to the input shaft,
and is in constant mesh with the intermediate shaft
second speed gear. Because of this constant mesh,
the intermediate shaft second speed gear freewheels
until second gear is selected. As the gearshift lever is
moved to the second gear position, the 1-2 fork moves
the 1-2 synchronizer sleeve towards second gear on
the intermediate shaft. The synchronizer sleeve
engages the second gear clutch teeth, fixing the gear
to the intermediate shaft, and allowing power to
transmit through the intermediate shaft to the differ-
ential (Fig. 5).
Fig. 5 2nd Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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3RD GEAR
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. The
input shaft third speed gear is in constant mesh with
the intermediate shaft 3-4 cluster gear, which is fixed
to the intermediate shaft. Because of this constant
mesh, the input shaft third speed gear freewheels
until third gear is selected. As the gearshift lever is
moved to the third gear position, the 3-4 fork moves
the 3-4 synchronizer sleeve towards third gear on the
input shaft. The synchronizer sleeve engages the
third gear clutch teeth, fixing the gear to the input
shaft, and allowing power to transmit through the
intermediate shaft to the differential (Fig. 6).
Fig. 6 3rd Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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4TH GEAR
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. The
input shaft fourth speed gear is in constant mesh
with the intermediate shaft 3-4 cluster gear, which is
fixed to the intermediate shaft. Because of this con-
stant mesh, the input shaft fourth speed gear free-
wheels until fourth gear is selected. As the gearshift
lever is moved to the fourth gear position, the 3-4
fork moves the 3-4 synchronizer sleeve towards
fourth gear on the input shaft. The synchronizer
sleeve engages the fourth gear clutch teeth, fixing
the gear to the input shaft, and allowing power to
transmit through the intermediate shaft to the differ-
ential (Fig. 7).
Fig. 7 4th Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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