2001 Oldsmobile Alero Transmission problems - no first gear

Tiny
TSZCZOTKA
  • MEMBER
  • 2001 OLDSMOBILE ALERO
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 110,000 MILES
My wife's 2001 Alero suddenly will not go into reverse, just from Park to Drive and seems to be skipping first gear. This is an automatic transmission, original with 110K+ miles. At around 40mph, it seems to want to downshift (or tries to). I experienced the problem when I picked up the car to drive home.

Any thoughts on what the problem could be or how to fix?
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Wednesday, October 20th, 2010 AT 9:17 AM

1 Reply

Tiny
FACTORYJACK
  • EXPERT
In most cases reverse is all mechanical and suggests an internal transmission problem, by that I mean there is no electrical influence that will cause no reverse. You have no first gear, is that drive range first gear, or manual 1st. If you have no manual first, it does have something in common with reverse, and that it relies on the lo/reverse band being applied. Drive, Drive 3, and second achieve first gear in different fashion. To be correct, the shifter lands in reverse, but there is no reverse motion. Here is a list of possibilities for no reverse/slips in reverse.
No Reverse or Slips in Reverse
Checks
Causes

Reverse Clutch
No apply or slipping

Piston and Seal Assembly (457)
Binding, cracked, or leaking

Inner Seal (456)
Plugged orifice

Clutch Plates (460-463)
Worn friction or broken splines

Snap Ring (459, 464)
Out of position

Housing (454)
Cracked, plugged feed holes, or broken tangs

Housing Retainer and Ball Assembly
Missing or out of position

Springs (458)
Binding

Reverse Clutch Fluid Routing
Fluid leak or restriction

Driven Sprocket Support (95)
" Leaking seal rings

" Porosity, damage, misalignment

Channel Plate and Gasket, and Valve Body, Gaskets, and Channel Plate
Porosity, fluid leak across the channels, misalignment, damage, or fluid restriction

Low and Reverse Band and Servo
No apply or slipping

Servo Piston (69)
Broken or binding

Servo Piston Seals (71, 72)
Leaking

Servo Pin (67) and Springs (66, 68)
Binding

Servo Cover (73)
Broken, loose, or leaking

Low and Reverse Band (111)
Broken, worn, or out of position

Anchor Pin (64)
Broken

Fluid Feed Tubes (83)
" Broken, bent, or plugged

" Missing or leaking seal rings

Transmission Case (1)
Porosity, fluid leak, or restriction

Shift Linkage
Disconnected or misaligned

Manual Valve (800) and Link (802)
Disconnected or misaligned

#1 Checkball
Missing, no low band fluid

Fluid Level
Low

Fluid Pressure
Low

Refer to High or Low Line Pressure.

And no first/slips in first

No First Gear, Slips in First Gear
Checks
Causes

Forward Clutch
No apply or slipping

Piston and Seal Assembly (607)
Binding, cracked, or leaking

Inner Seal (608)
Plugged orifice

Clutch Plates (601-604)
Worn friction, or broken splines

Snap Ring (600, 605)
Out of position

Housing (609)
Cracked, or plugged feed holes

Housing Retainer and Ball Assembly
Missing or out of position

Springs (606)
Binding

Input Sprag (515)
Damaged or not holding

Lo Roller Clutch (652)
Damaged or not holding

Forward Clutch Fluid Routing
Fluid leak or restriction

Oil Feed Tubes (83)
" Bent, broken, or plugged

" Leaking seal rings

Forward Clutch Support (114)
" Porosity

" Leaking or damaged seal rings

" Plugged feed holes

Channel Plate (27) and Gasket (28)
" Porosity

" Misalignment

" Fluid leaking across the channels

" Restriction

PSA (13)
Leaking drive switch O-ring

1-2 Shift Solenoid Valve (305)
" Failed OFF

" Leaking

1-2 Shift Valve (302)
Stuck in upshifted position

2-3 Shift Solenoid Valve (305)
" Failed ON

" Plugged exhaust

" Manual Valve (800)

" Shift Linkage
Misalignment

Torque Converter (55)
Stator roller clutch is not holding

Line Pressure
Low Pressure

Refer to High or Low Line Pressure.
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Thursday, October 21st, 2010 AT 12:01 AM

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