Clutches and Hydraulics - Transmission Components

We carry J&W Transmissions

JW Transmission Care FAQ's


1. How often should I change my fluid?

Every 25 to 40 runs depending on application. Fluid should look clean. If it starts to look dirty or smells burnt than you should change it sooner.

2. How often should I rebuild my transmission?

Every 250 passes for those with less than 1,200 horsepower. Those with over 1,200 horsepower every 100 passes.

3. What is considered a good temperature for my transmission?

160 to 200 degrees F. Over 200 degrees F is considered too hot and will create heat damage to the band and clutches.

4. How often should I rebuild my torque converter?

Every twelve to eighteen months is the suggested time frame.

5. How much fluid does my transmission hold?

Powerglide with deep pan = 9 quarts

Powerglide w/o deep pan = 7 quarts

TH400 with deep pan = 9 ½ quarts

TH400 w/o deep pan = 7 ½ quarts

TH350 with deep pan = 9 ½ quarts

TH350 w/o deep pan = 7 ½ quarts

6. If my solenoid has two wires what should I do with the second wire?

The second wire needs to be ground to the pan or to another location on the transmission.

7. How do I install my torque converter?

Fill the converter with ½” of a quart of transmissions fluid. Install the converter onto the front pump. When installing the converter, insert into the crank pilot 1/8” to 3/16”. There should be 1/8” to 3/16” of clearance between the flywheel and converter mounting lugs.

8. How many amps should my solenoid draw?

All solenoids draw between 6 to 7 amps.

9. How do I identify the cooler lines?

The bottom line is pressure and the top line is the return line, for all GM applications.

The front line is pressure and the back line is the return for the C-4 and TF727 or TF904 applications.

10. What increases or creates stall speed?

The torque multiplication exists when more torque is applied to the turbine through redirected fluid force from the impeller, which is operating at a lesser torque. This condition is commonly called Vortex fluid.

The pitch of the fin angle determines the fluid velocity flow and therefore determines the stall speed. The greater the pitch of the fin angle the more stall is created.

11. How do I adjust my band?

The powerglide, C-4, TF727 and TF904 are the only transmissions that need a band adjustment. The TH350 and TH400 do not require a band adjustment.


Loosen the 9/16” jamb nut tighten the bolt within 7/32” allen wrench to 72 inch pounds.

Back the adjusting screw to 3 ¾ turns. The band should be adjusted every 25 runs.



  • Remove lock nut
  • Tighten adjusting screw to 10 foot pounds
  • Back out three turns
  • Install lock nut and tighten


  • Loosen lock nut
  • Tighten adjusting screw to fit 10 ft. pounds
  • Back out 1 ½ turns for coarse thread
  • Back out 2 ½ turns for fine thread
  TF727 and TF904

Front Band:

  • 4.2/5/0 lever: 1 ¾ turns - CCW (off)
  • 3.2/3.8 lever 2 turns - CCW (off)

Rear Band:

  • 2 turns - CCW (off)


12. What are the typical causes of oil leaking (puking) out of a transmission?

A. Too much oil

B.  Pump halves not flush, causing a cross leak into vent or into drain, causing foaming.

C. VB cross leak blowing out into oil, therefore foaming the oil.

D.  Pump gaskets blown on pressure or suction side.

E.   Broken torque converter, or too much torque converter clearance.

F. Over heated oil, which raises the overall oil level.

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