How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Shannon Martin Your Own Question
Shannon Martin
Shannon Martin, ASE Certified Master Technician
Category: Chevy
Satisfied Customers: 589
Experience:  over 20 years as a line technician both asian and domestic.
48411850
Type Your Chevy Question Here...
Shannon Martin is online now
A new question is answered every 9 seconds

1991 CHEVY: SOMETIMES IT WILL NOT SHIFT INTO OVERDRIVE.40,

This answer was rated:

I HAVE A 1991 CHEVY W/ 454 ENGINE AND HYDROMATIC TRANSMISSION , SOMETIMES IT WILL NOT SHIFT INTO OVERDRIVE.
40,000 MILES .
hi i am shannon i see you have been waiting a long time for help .i will help on this issue if you still need it. just post back and let me know. thanks shannon
Customer: replied 5 years ago.
yes i need your help. thanks

the biggest issue for on overdrive is at the brake light switch. its the light switch that stops the power to overdrive or lock up converter.but first i need to know which trans you have . please count the bolts that hold the oil pan on .this one has 17

 

graphic

graphicgraphic
Customer: replied 5 years ago.
17 bolts .

ok the very first thing to do is too see if you have any transmission codes in the computer . you can go to a parts store like Auto zone .they will retrieve the codes for you at no cost .or you can retrieve them your self with a paper clip. hear is how you do that.

 

graphicgraphic

 

 

please let me know what codes you find. if any. thanks

Customer: replied 5 years ago.
hello, and thank you for your help . it will be monday before i can get codes to you . ROGER
no problem Roger i,ll be available until 6/10/2011 then i will be in Jamaica for a week vacation.
Customer: replied 5 years ago.
hello, hope you are having a good holiday. i looked under dash driver side an could not find aldl connector. i will get back later when i find it . thanks roger

by law it is supposed to be on the driver side .it could be under the driver seat.

Customer: replied 5 years ago.
hello, i have looked under dash and under drivers seat. i have found the aldl connector on both my other trucks. i call fleetwood motor homes they said they had no location on aldl until 1996 and they said they don't relocate it. maybe it was remove over the years . please tell me what you are thinking about brake light switch. thanks ROGER XXX-XXX-XXXX.
graphicgraphicif .graphicgraphic
if you have found the computer ( ECM ) you can run a ground wire to pin D6 that will start the codes to start flashing out at the check engine light.i am sending you the ECM diagram and the pin voltage charts. these charts tell you what voltage you should get at the ECM pins with the key on and with the engine running. you should test any grounds to the negative battery post voltage reading must be less than 0.10vdc for grounds
Shannon Martin and 3 other Chevy Specialists are ready to help you
Customer: replied 5 years ago.
thank you i may use your service again.
no problem you can request me any time i am tech sgm11155

Related Chevy Questions