DODGE TOWN AND COUNTRY 2001 Service Manual

T850 MANUAL TRANSAXLE
DESCRIPTION
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)
21a - 2 T850 MANUAL TRANSAXLERG
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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.
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 orintermediate 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 untilfirst 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 ismoved 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 freewheelsuntil 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 gearshiftlever 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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5TH GEAR
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. The
input shaft fifth gear is pressed on to the input shaft,
and is in constant mesh with the intermediate shaft
fifth speed gear. Because of this constant mesh, the
intermediate shaft fifth speed gear freewheels untilfifth gear is selected. As the gearshift lever is moved
to the fifth gear position, the 5-R fork moves the 5-R
synchronizer sleeve towards the intermediate shaft
fifth speed gear. The synchronizer sleeve engages the
fifth gear clutch teeth, fixing the gear to the input
shaft, and allowing power to transmit through the
intermediate shaft to the differential (Fig. 8).
Fig. 8 5th Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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REVERSE GEAR
Engine power is transmitted to the input shaft via
the clutch assembly and the input shaft turns. The
input shaft reverse gear is integral to the input
shaft, and is in constant mesh with the reverse idler
gear. The reverse idler gear, which reverses the rota-
tion of the intermediate shaft, is in constant mesh
with the intermediate shaft reverse gear. Because of
this constant mesh, the intermediate shaft reversegear freewheels until reverse gear is selected. As the
gearshift lever is moved to the reverse gear position,
the 5-R fork moves the 5-R synchronizer sleeve
towards the intermediate shaft reverse gear. The
synchronizer sleeve engages the reverse gear clutch
teeth, fixing the gear to the intermediate shaft, and
allowing power to transmit through the intermediate
shaft to the differential (in reverse) (Fig. 9).
Fig. 9 Reverse Gear Operation
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T850 MANUAL TRANSAXLE (Continued)
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DIAGNOSIS AND TESTING - COMMON
PROBLEM CAUSES
The majority of transaxle malfunctions are a result
of:
²Insufficient lubrication
²Incorrect lubricant
²Misassembled or damaged internal components
²Improper operation
HARD SHIFTING
Hard shifting may be caused by a misadjusted
crossover cable. If hard shifting is accompanied by
gear clash, synchronizer clutch and stop rings or gear
teeth may be worn or damaged.
Hard shifting may also be caused by a binding or
broken shift cover mechanism. Remove shift cover
and verify smooth operation. Replace as necessary.
Misassembled synchronizer components also cause
shifting problems. Incorrectly installed synchronizer
sleeves, keys, balls, or springs can cause shift prob-
lems.
NOISY OPERATION
Transaxle noise is most often a result of worn or
damaged components. Chipped, broken gear or syn-
chronizer teeth, and brinnelled, spalled bearings all
cause noise.
Abnormal wear and damage to the internal compo-
nents is frequently the end result of insufficient
lubricant.
SLIPS OUT OF GEAR
Transaxle disengagement may be caused by mis-
aligned or damaged shift components, or worn teeth
on the drive gears or synchronizer components. Incor-
rect assembly also causes gear disengagement. Check
for missing snap rings.
LOW LUBRICANT LEVEL
Insufficient transaxle lubricant is usually the
result of leaks, or inaccurate fluid level check or refill
method. Leakage is evident by the presence of oil
around the leak point. If leakage is not evident, the
condition is probably the result of an underfill.
If air±powered lubrication equipment is used to fill
a transaxle, be sure the equipment is properly cali-
brated. Equipment out of calibration can lead to an
underfill condition.
CLUTCH PROBLEMS
Worn, damaged, or misaligned clutch components
can cause difficult shifting, gear clash, and noise.
A worn or damaged clutch disc, pressure plate, or
release bearing can cause hard shifting and gear
clash.
REMOVAL
REMOVAL - 2.4L GAS
(1) Raise hood.
(2) Disconnect gearshift cables from shift levers/
cover assembly (Fig. 10).
(3) Remove gearshift cable retaining clips from
mounting bracket (Fig. 10). Remove cables and
secure out of way.
(4) Remove three (3) right engine mount bracket-
to-transaxle bolts (Fig. 11).
(5) Raise vehicle on hoist.
(6) Remove front wheel/tires and halfshafts.
(7) Drain transaxle fluid into suitable container.
(8) Remove cradle plate.
(9) Remove front harness retainer and secure har-
ness out of way.
(10) Remove clutch release access cover.
(11)RHD Models:Using Tool 6638A, disconnect
clutch hydraulic circuit quick connect (located on
slave cylinder tube). Remove clutch slave cylinder by
depressing towards case and rotating counter-clock-
wise 60É, while lifting anti-rotation tab out of case
slot with screwdriver (Fig. 12).LHD Models:
Remove clutch release cable by pulling outward on
cable housing, then forward to allow cable core to
pass through case slot (Fig. 13). Disengage T-end
from release lever and secure cable out of way.
(12) Remove engine left mount bracket.
(13) Remove starter motor (Fig. 14).
Fig. 10 Gearshift Cables at Transaxle
1 - SELECTOR CABLE
2 - CABLE RETAINER
3 - CABLE RETAINER
4 - CROSSOVER CABLE
5 - MOUNT BRACKET
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T850 MANUAL TRANSAXLE (Continued)
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