Sep 032011

General Motors 4L60, Th700, Th700R4 & Turbo 700 Line Pressure For 4L60/TH700 Transmission

4L60/TH700 Line Pressure Port Location

4L60/TH700 Line Pressure Port Location

Line pressure is a key factor for all automatic transmissions the following information will help Diagnose oil pressure related issues.

Using a 0-100psi oil pressure gauge and the appropriate adapter connect into the port making sure not to over tighten and risk cracking the housing.

With the transmission fluid level correct and at normal operating temperature with T.V cable set correctly. The line pressure @ 1200rpm should be 70 to 80 psi in Park, Neutral, Overdrive and Drive.

Diagnoses Information

  • If Overdrive & Drive have a lower pressure it points to an internal leak.
  • If Park & Neutral have a lower pressure than 50 psi it points to either a Filter or Pump related Problem.
    If the pump pressure is between 50psi and 60psi its recommended to install a stronger pressure regulator spring.
  • If pressure is above 80 psi its either a valve body or pump related issue the valve body can be eliminated by removing the sump and removing the T.V. plunger and fitting the sump with a few bolts and testing again if the oil pressure drops off its a valve body problem if it’s still high it’s a pump related problem.
    Tips:  Try and save as much fluid in the sump as possible to save refilling. To remove the plunger just remove the pin and remove it completely for testing purposes only.
Reverse Line Pressure
  • Engine Idle in Reverse gear 120-125 psi (Requires a 400psi Gauge).

See Also…

A list of GM Transmissions


Sep 032011

Setting the T.V. Cable on 4L60/TH700 Automatic Transmission

Setting Conditions

Holden Commodore TH700 TV Cable Adjustment

Holden Commodore TH700 T.V Cable Adjustment

  • Test drive first and note shifting speeds and kick down speeds.
  • Car parked with engine NOT running transmission in park.
  • Make sure when Throttle pedal is at Full Throttle the Throttle body also has 100% Throttle.

Setting Procedure

  • Release the cable lock and pull the cable away from the throttle body until its stops then allow it to lock.
  • Now open up the throttle body to full throttle either by hand or using the throttle pedal this cant be done to fast it may over adjust.
  • This is now set to the MAXIMUM T.V Setting you can mark with white out for a point of reference.
  • Test Drive the Vehicle and note the shifting speeds and kick down speeds.
  • You may need to allow for 1 click towards the throttle body.

Test Drive Procedure

  • Make a light Throttle 1-2 up shift then full throttle to preform a 2-1 down shift. This can be preformed as soon as the transmission shifts into 2nd gear.
  • Next at a legal speed area or 60kmh in 3rd (Can have it selected with shifter) full throttle to preform a 2-3 down shift.
  • These shifts should be achievable at either 1 click or Maximum T.V. adjustment.

No Success?

  • The T.V. valve in the valve body is prone to sticking as well as the governor you could try a transmission treatment if caught early enough. The T.V. valve can be worked while driving but if it sticks again in a short period of time its need to be repaired. When the sump is removed and there are no signs of transmission debris on magnet or bottom of sump a good valve body clean will fix the issue. If the sump is full of metal and material it will only stick again until the internal problem is fixed.

Australian Vehicles fitted with 4L60/TH700 Transmission

  • Holden VN Commodore (1988-1991)
  • Holden VP Commodore (1991-1993)
  • Holden VG Commodore UTE
  • Holden VQ Statesman
  • Toyota Lexcen (1988-1993)

See Also…