QuestionMy wife has a 2001 LeSabre, 3.8 V6, auto trans with overdrive @ 75,000 miles. I drove it the other day and it will not shift into OD at any time.When I let off the accelator, the engine speed drops to idle. What could be causes ?
AnswerHi
There are MANY things that can cause no fourth gear.
I'll laist them last.
My best advice would be to FIRST take it to a GOOD repair shop OR a GOOD transmission repair shop and have the computer scanned for codes. There RAE some codes that WILL not turn on the Service engine soon light, but will inhibit fourth gear.
Have them drive it, watching the data while driving may help in diagnosis.
Thats my best advice.
Here is a list of items that can cause no fourth:
Automatic Transmission Fluid Level
Low fluid level
Transmission Main Line Pressure
Low transmission main line pressure
Oil Filter Assembly
• The oil filter assembly is missing, plugged, or damaged.
• The oil filter seal assembly is missing or is damaged.
Control Valve Body Assembly
• The 3-4 shift valve or the 4-3 manual downshift valve is stuck or binding.
• Debris is found in the passages of the control valve body or of the control valve body spacer plate and gasket assembly
Case Cover Assembly
Distortion or damage occurs at the manual valve or at the case cover ,causing PRN oil leak.
Driven Sprocket Support Assembly
A plugged third clutch oil passage in the driven sprocket support assembly
Fourth Clutch Assembly
• The clutch plates worn, damaged, or misassembled.
• A missing or not seated fourth clutch spring retaining ring
• A damaged spring assembly or piston .
• Worn or damaged fourth clutch piston seals .
Third Clutch Sprag Assembly
• The sprag was misassembled or backwards on the inner race .
• A damaged third clutch sprag assembly
I Hope this helps.
Good Luck
PAwl
