48RE Shift Issue

[RockinRam96]

Hey guys. My dad has a 2005 with a 48RE and it is having trouble shifting into 3rd gear. Sometimes it will shift with out an issue, others you will have to be on and off the throttle to get it to shift. Once it shifts into 3rd it will shift in to O/D just fine.

The local shop says it is an o-ring in the clutch pack is torn and letting pressure bleed off. Seems to me if this were the case it wouldn't shift at all. Thoughts?

Fluid level is good. Not loosing fluid any where. Changed fluid and filter about a month ago and still same problem. Could it be the valve body? Speed sensor?

 

[raychem]

First thing first. Did you check fluid? Check in neutral with engine running and go by the lowest reading on the dip stick.

Sounds like the governor solenoid. Change it out along with the governor pressure sensor and adjust the bands while your there too.

If you have access to someone with a good scanner that can get into the transmission, you can see what is going on in there to. But based on what your saying, I would do this first.

 

[RockinRam96]

First thing first. Did you check fluid? Check in neutral with engine running and go by the lowest reading on the dip stick.

Sounds like the governor solenoid. Change it out along with the governor pressure sensor and adjust the bands while your there too.

If you have access to someone with a good scanner that can get into the transmission, you can see what is going on in there to. But based on what your saying, I would do this first.

I have checked the fluid and checked it properly. I️ did say in my original post that the fluid level was good.

The same shop had changed the pressure solenoid a few years ago. They’re saying it won’t fix the problem this time. I️ don’t know maybe worth a shot.


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[RockinRam96]

Governor pressure solenoid and governor transducer solenoid have been replaced. Problem still exist.


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[raychem]

Check the TVVA motor on the side, make sure it is working. You can be under the truck and have someone open the switch. The motor will cycle as it always does when it starts.

You can do a pressure test. The front port on the transmission nearest the dipstick on passenger side put a 200 psi pressure gauge on it and see if there are any differences in the pressure when it shifts fine vs when it does not. Pressure with stock VB should be in the 55-60 psi range @ 45 mph. 100 psi or more with modified VB.

You do not mention if the VB has a shift kit, is from a builder or if it is stock. Sounding to me like a VB problem or bad worn seals on the pistons as was told to you earlier. I have seen VBs with shift valves getting stuck or with worn bores.

I should also have asked, How many miles on this truck; transmission? Transmission due wear out at some point.