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Shifting Problems

Load*,8,1

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Load*,8,1 Enthusiast

Load*,8,1

Posted
Posted

When I leave my truck sit for a few hours (overnight or after work) and shift from reverse to drive, it normally takes a good 10 seconds before it shifts.

 

Is this a sign that my tranny is going out?  It started doing it about a month or two ago

 

Josh

Beaux Duke Enthusiast

Beaux Duke

Posted
Posted

Does it only do it when it's cold?  Have you checked the fluid level?  Seen any leaks when parked on concrete?

 

My son-in-law had that problem with his K5 Blazer.  Turned out to be a bad torque converter and low fluid.  (One probably led to the other)

 

I hope you're just low on fluid.

Load*,8,1 Enthusiast

Load*,8,1

Posted
  • Author
Posted

fluid is fine.  i live in the south so it hardly gets cold.  it is getting colder now but this started a month or so ago when it was warm.

 

it scared me this morning.. took about 15-20 seconds to shift into drive and it was pretty chilly outside.

 

only leaks i see are oil leaks from my rear gaskets.

Beaux Duke Enthusiast

Beaux Duke

Posted
Posted

Have you ever changed the fluid?  Check the condition of the fluid. If the fluid is badly discolored, it indicates oxidation and a need for replacement. A burnt odor would also tell you the fluid has gotten too hot and needs to be replaced.

 

A quick way to test for worn transmission fluid is to do a "blotter" test. Place one or two drops of ATF from the transmission on a paper towel and wait 30 seconds. If the spot is widely dispersed and red or light brown in color, the fluid is probably OK. But if the spot does not spread out and is dark in color, the ATF is oxidized and should be changed.

 

If the fluid needs to be changed, a simple drain and fill (dropping the transmission pan and replacing the filter) is better than no maintenance at all. But a simple drain and fill procedure leaves up to three-quarters of the old fluid inside the torque converter. A better approach is to use flushing equipment to achieve a total fluid exchange.

 

If the fluid appears to be fine, the next thing to check would be the operating pressure inside the transmission or transaxle.  If you don't have a pressure checking gauge or access to one, it might be best to have a tranmission shop perform this step.  

 

Before you take any readings, you should first look up the reference specifications for the transmission in a shop manual along with any illustrations that might be needed to help you locate the correct connection for your pressure gauge.

 

It might also be the torque converter.  A problem that affects the operation of the torque converter is "transmission drainback." One-way check valves normally keep the torque converter full of fluid when the engine is shut off. But if the transmission input shaft bushings are worn, it can create a path for fluid to drain out of the converter back into the transmission. The loss of fluid from the torque converter can make the transmission feel as if it is slipping on initial take-off for about five to 10 seconds.

 

It sounds like drainback may be the problem rather than ambient temperature.  Sitting overnight allows the fluid to drain from the torque converter.  If you're quick enough you can have someone start the vehicle while you check the fluid level during the first few seconds of startup.  If the stick reads over full then drainback is the likely cause.

 

Delayed engagement from Neutral to drive is usually associated with, but not limited to, one of the following causes.

 

Engine performance

Worn or faulty underdrive clutch

Worn or faulty 2-4 clutch

Worn or faulty low/reverse clutch

Damaged clutch seal

Worn or damaged accumulator seal(s)

Worn or faulty shaft bushings (Drainback)

 

Before you go to a shop you may want to consider pouring in a can of TransMedic or some other brand of transmission flush/cleaner, driving the vehicle for the prescribed distance on the can then dumping the pan and changing the filter.

 

I'm hoping it's just a sticky modulator valve but if you have a high mileage vehicle it may be time for another transmission.

 

Good luck!  :thumb:

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