Overdrive and lockup
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Overdrive and lockup On my trip last weekend the MPG was just under 20 but thought it should have been better. Stock 2003 LM4 5.3 engine with stock 4L60E trans. Rear gears are 3.73 with a 26" tire. Car is a '39 Chevy at 3300 lbs. How can I tell if it goes into overdrive? Lockup?
On The Tree
Joined: Feb 2014
Posts: 157
Likes: 3
You can tell if it has locked up the converter by driving it at speed, when you think the converter should be locked up touch the brake lightly. Do not let off the throttle. Look at the tach if you have one and if it was locked up, the RPMs should go up by a couple hundred or so RPM.
Same with OD. If you think you should be in fourth, look at the tach, down shift to manual third. RPMs should drop.
Also, if you have a scanner or access to one, you can look there.
Same with OD. If you think you should be in fourth, look at the tach, down shift to manual third. RPMs should drop.
Also, if you have a scanner or access to one, you can look there.
TECH Enthusiast
Joined: Mar 2013
Posts: 502
Likes: 38
You can tell if it has locked up the converter by driving it at speed, when you think the converter should be locked up touch the brake lightly. Do not let off the throttle. Look at the tach if you have one and if it was locked up, the RPMs should go up by a couple hundred or so RPM.
Same with OD. If you think you should be in fourth, look at the tach, down shift to manual third. RPMs should drop.
Also, if you have a scanner or access to one, you can look there.
Same with OD. If you think you should be in fourth, look at the tach, down shift to manual third. RPMs should drop.
Also, if you have a scanner or access to one, you can look there.
You can tell if it has locked up the converter by driving it at speed, when you think the converter should be locked up touch the brake lightly. Do not let off the throttle. Look at the tach if you have one and if it was locked up, the RPMs should go up by a couple hundred or so RPM.
Same with OD. If you think you should be in fourth, look at the tach, down shift to manual third. RPMs should drop.
Also, if you have a scanner or access to one, you can look there.
Same with OD. If you think you should be in fourth, look at the tach, down shift to manual third. RPMs should drop.
Also, if you have a scanner or access to one, you can look there.
T,
