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Discussion Starter · #1 ·
Hello,
So it won't shift automatically. If you pull shifter down to 1st you can pull shifter to 2cd but won't up shift to 3rd. If you do manually up shift to 3rd, you can feel it and see the slip in the tach.
No diagnostic codes found on NGS scanner in ANY self test in PCM using diagnostic card.
I say it is HD 4 R100. What say you all auto transmission guys?
Thanks
Nick
 

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Does reverse work?
 

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Discussion Starter · #3 · (Edited)
Hi Mark, yes it feels strong. It's been sitting for a few years. It had a flat tire with the parking brake seized activated on that wheel. Lock up felt strong. It would load up the engine. I would press hard on pedal and freed up wheel started spinning on the asphalt. Unseized brake, replaced tire and it felt pretty darn strong in reverse.
Upon leaving driveway it up shifted to second weakly but no 2-3 up shift. I pulled the shifter down to 1st then tried pulling it into 2 and it actually felt like a strong shift but it would not automatically upshift to 3rd. So I manually pull it up and it was major majorly slipping.
Not an auto trans guy but in my mind I visualize a reverse clutch in good shape but forward clutches are roasted but that from a non auto trans Guy's semi wild guess.
I don't need to do the " parking brake on, pedal to the floor line pressure test,do I ?
I appreciate the help on this. Also was doing this prior to sitting.

Thank you.
BTW Mark it's 152k miles. It also hauled a 30ft. Offshore Fountain speed boat. I have seen them, don't know how much they weigh but that boat looks way to heavy to be hauling with a pickup.
 

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I went to bed. It was a long weekend.

My guess is that the 2-3 shift valve is stuck. Reverse uses the reverse clutch and the direct clutch. Third gear adds the direct to the already on intermediate clutch. Since reverse is fine we know the direct works. That points to the shift valve.
 

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Discussion Starter · #6 ·
I know how that is buddy. It's been insanely hot here. I was weak yesterday from the heat of the past few days.
Is that rascal hard to get to?
 

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It's inside the valve body.
 

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Discussion Starter · #8 ·
Thanks,
Can I confirm this before pulling the pan? Line pressure test? If confirmed, is it advisable to install a new valve body?
I do not stock parts like that so if it's not the problem, I can't pull it back out and put on a parts shelf. The valve body can be replaced by accessing it by removing pan, correct?
 

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Discussion Starter · #9 ·
BTW Mark, if you see me post and my name as viewing disappear, it's because replies will not appear on my screen unless I leave thread and come back.
 

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Thanks,
Can I confirm this before pulling the pan? Line pressure test? If confirmed, is it advisable to install a new valve body?
I do not stock parts like that so if it's not the problem, I can't pull it back out and put on a parts shelf. The valve body can be replaced by accessing it by removing pan, correct?
A line pressure test won't show that. The only way I know to confirm that the valve is sticking is by removing the pan and valve body and then checking to see if the valve is stuck.
 

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It will not be self evident. I would need a valve body diagram to know which valve it is, I expect you would, too. I don't have one, but they can be found by a search.

It directs pressure to the direct clutch when a 2-3 shift is commanded.

A line pressure test checks line pressure. That seems too obvious, doesn't it?
 

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Discussion Starter · #13 ·
Thank you,
No it does not seem to obvious to me. Regarding different line pressure readings. Why? Because I don't know the hydraulic circuits, where that port is in the circuitry. Not knowing the lay out, wouldn't it be reasonable for a tech to ask or have a line of thinking that if a valve was hanging in this circuit someplace that, that tech might be able to see a loss off pressure or even a rise in pressure befor or aft of this offending valve and think it might be seen in that port? Wouldn't that be a reasonable if not logical question to ask an auto trans guy?
 

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Discussion Starter · #14 ·
Mark, If the valve body is removed, will parts rain down? Once on bench and the 2-3 valve is identified, will it be self evident once then removed from valve body that it is the cause of this truck's transmission shifting and oporational problem and not something further into the transmission like smoked clutches or something else?
 

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Check balls will fall out. Locate diagram to get them back where they belong. If the valve is stuck in the bore you can be quite sure that's the problem. If not, then I don't know.
 

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Discussion Starter · #16 · (Edited)
Thank you Mark. I have found you very helpful to me and I appreciate that fact. You pointed me in a direction here. You were helpful to me when I did the Derale bypass valve to keep my trans temps up as you recommended for the purpose of keeping moisture out of fluid ( if my memory serves me correctly ( hate egg shells ) ). Trans lives hotter, no question there. It with the 6.0 cooler together get keep temps up but even in one if the worst blizzards in history it would get upto 180, open and control it. I NEVER rose above 190 pushing massive snow. From this I saw the cooling effeiciency of that cooler. You say it's healthier to be up near 180, which I cannot get to on the hottest day (usually can't get past 160) ( used to stay way lower ) and lots of vehicles are keeping trans temperatures hotter, soooo Im happy.

Customers truck: 250k hauling massive boat. It's getting its frame stripped painted and full mechanically reconditioning, new cab corner, new bed, new paint job. Owner getting reflective bill.
My thoughts on how to view this condition, picturing overall condition of this transmission knowing its hauling history; I picture pulling that valve body off, worn balls falling down and then going back into worn bores they did not live in despite all the bores getting balls back into them. I picture this fix and overall condition of trans leaving it in a collective state that is not worthy of the quality the truck will become.
Do you feel that this trans could be made reliable with this fix if it was infact the problem, by say... Pulling the valve body off , confirming that is the issue, fixing that 2-3 valve ( reconditioning the physical valve itself? ) Or just putting a whole new valve body on and have this thing reliable and the owner with that smile for a good while?:smile2::smile2:

Mark to Nick.... Not there Not in it.?

Love ya brother
 

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I think the valve body can be reliable if it is cleaned and any stuck valves repaired as needed.
 
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