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I am having issues with delayed/harsh forward and reverse engagements. Once the truck is in gear it shifts fine and everything seems okay. I found this TSB that describes my issue but I am was wondering if anyone had any experience changing this solenoid and could tell me where it is and how to get at it and if it fixed their issue. Thanks!
Harsh or Delayed Forward or Reverse Engagement:
This could be caused by a sticking line pressure control (PC-A) solenoid. Typically the line pressure will be fluctuating wildly (up to 500 PSI!). To service, first remove and inspect the external cooler line filter. If it contains fine gray metallic debris. If metal is found, the source is most likely a defective reverse planetary pinion shaft that is coming out of the carrier and contacting the case or adjacent components. The transmission will need to be disassembled and repaired as needed or replaced. Broadcast Message 3250
If little or no debris is found replace the line pressure control solenoid with P/N 4C3Z-7G383-AA. Broadcast Message 1586/SSM 17874/18051
This repair will require removing the solenoid harness, so a new harness sealing o-ring (P/N 3C3Z-7Z276-AA) will need to be installed. In some cases the solenoid body will need to be removed from the trans to remove the harness and solenoid. In this case the solenoid body gasket (basic P/N 7C155, trans tag number needed) will be needed as well. Note: Do not loosen the 10mm head bolts on the solenoid body. Only loosen the 8mm head bolts.
If the solenoid has been replaced and the condition it still present, suspect a contamination issue of the solenoid or a sticking pressure relief valve.
Not really that hard. You ned to have things as clean as you can make them.
The solenoids are only held in in most cases with an "E" clip.
The ones that are a PITA are ones that you have to remove the valve body
do to location and clearance issues. Not sure if the PC-A is one of those or not.
Here is a diagram on this linked PDF. http://www.trucktransdiag.com/downlo...nical-info.pdf
I also added it to the thread so you can download it.
I had some photos of the valve body but that was on a drive that bit the dust.
No use crying over spilled trans fluid.
I'll see if I can get a good clear photo to post for you.
I think the worst part about doing the work in the truck is the dripping.
Also when you remove the filter 2 things will/may happen.
1. The fluid above the filter neck will dump out on you because you (I did anyway)
think all the draining is done.
2. The little rubber seal will stick in the bore. Use plastic tools to pull it out
so you don't scratch the bore.
Fantastic, thanks for all of the info! I am going to get a gauge and check the line pressure, hopefully it will point to this solenoid being the issue and not some bigger issue.
I might be able to get them. I have not finished rebuilding
the computer I use for that but I might be able to get the
needed files some other way. I'll let you know later tonight.
So at idle in park it fluctuates pretty quickly between 50-125 psi, in reverse it fluctuates very rapidly between 100-200 psi, in drive it fluctuates from 100-150 psi. Seems to me that it points to that line pressure control solenoid being bad. Would everyone else agree?
Also will it damage the transmission to drive it in this state?
Can anyone confirm whether or not you have to remove the valve body to replace the PC-A solenoid? The reason I ask is because the solenoid and the harness oring are in stock at the dealer but the body gasket has to come from a few states away which seems weird that they would keep the solenoid in stock but not the gasket to replace it.
So you think I will just need a solenoid and the oring for the harness and not the actual valve body gasket? Thank you very much for your help I really appreciate at!
I am not sure on the gasket because there is also one between the valve body halves.
A little later when I get some space on the table I can see about replacing that bad
power supply and get the PC back up and make you some PDFs for the job. I think
you will need the one but not the filter gasket that goes between. I really need to
look at the workbook to see what it says for the best answer.
I will check my line pressure tomorrow night and report back.
