Seville V8-273 4.5L (1989)
Throttle Valve Assembly: Customer Interest
A/T - Shift Timing Problems
Bulletin No.
T-90-93
File in Group
7
Number
224
Corp. Ref. No.
077106
Date
July, 1990
SUBJECT:
INTERMITTENT TRANSMISSION SHIFT TIMING CONCERNS - TV SYSTEM DIAGNOSIS AND PARTS
AVAILABILITY FOR SERVICE - HYDRA-MATIC, 4T60 (THM 440-T4)
MODELS AFFECTED:
1985-1990 DE VILLES AND FLEETWOODS 1986-1990 ELDORADOS AND SEVILLES
Some 1985-1990 DeVilles and Fleetwoods or 1986-1990 Eldorados and Sevilles may exhibit transmission shift timing (not shift feel) conditions that
may be described as:
^
Delayed upshifts
^
Early upshifts
^
No upshifts
^
1-2 shift at full throttle only
^
No full throttle or part throttle detent downshifts
^
Intermittent second gear starts
^
Harsh 3-2 downshifts
Any of these conditions may be caused by TV system problems.
Diagnosis Information:
TV System Diagnosis
1.
Check the TV cable for:
^
Correct part number.
^
Kinked, bound, disconnected, or broken condition.
^
Proper set.
Figure 1 - TV Plunger/Bushing and Throttle Valve
2.
With engine off, is there tension on the TV cable when it is pulled and released? If not, check for:
^
Disconnected throttle lever to cable link.
^
Broken TV cable.
^
A stuck TV plunger in the TV bushing. Refer to Figure 1, items 308 and 309. If the TV plunger/bushing assembly is worn, sticking, or
binding, replace the assembly with parts listed in service parts information.
3.
Does the TV cable lose tension once the engine is started? If it does, check for:
^
Throttle valve stuck in the bore. Refer to Figure 1, item 311. To repair this condition clean the valve and bore. Refer to bulletin T-86-45 for
proper service procedures. If the throttle valve moves freely in the bore, then the pump cover is mis-machined and should be replaced.
