Specifications

Power Train Testing and Adjusting 43
Problem: High stall speed in one direction.
Probable cause:
1. There is a leak in the clutch circuit.
2. There is a failure in that clutch assembly (clutch
slipping).
Problem: Selector spool problems.
1. Transmission stays in neutral, no shift.
Probable cause:
1. Spools mechanically stuck
a. Contamination
b. Case or body not flat
c. Bore / spool worn
2. Solenoids not working
a. O-rings leaking (cut)
b. O-rings missing
c. Ports not machined properly
d. Contamination in solenoid
e. Electrical problem
3. Orifice plugged
a. With debris
b. Bad part
4. Modulation valve stuck in "off" position
5. Modulation valve not correctly assembled.
2. Transmission will not shift into or out of 1 gear
Probable cause:
1. Spools mechanically stuck (same as above)
2. Solenoids not working (same as above)
3. Valve not correctly assembled (same as above)
4. Holes not drilled into case properly
5. Excessive leakage internally in body
a. Porosity in body
b. Selector bore too large
c. Spool too small
d. Slug/spool fit not right.
Problem: Modulation spool problems.
1. Slow or no modulation of both clutches
(If only 1 clutch does not modulate correctly then
the problem is either with the selector spool or it is
a problem in the transmission).
Probable cause:
1. orifice plugged with debris
2. Modulation valve stuck
3. Modulation valve not correctly assembled.
4. Load piston problem
a. Stuck in bore
b. Excessive valve / bore clearance
c. Missing springs
5. Porosity in body in the area of load piston cavity
2. Modulation time is too quick
Probable cause:
1. The upstream orifice (in the oil supply) is not
installed. (The orifice is located in the valve block)
2. The load piston is only moving a small amount
before it sticks. Check the spool to see if it freely
fits in the bore. This check must be made while the
aluminum body is still bolted down to the
transmission.
3. The plastic orifice is not installed or the hole in the
plastic housing is too large.
4. The modulating valve is stuck in an open position.
Check to see if the valve moves freely while the
aluminum body is still bolted down.
5. The springs are not installed or the pin has jammed
the load piston