48/47RE Experts needed - Help

[Ozymandias]

What am I looking at here?

The other day I noticed on my VDO gauge that my line pressure (measured at the accu port) is generally lower then used to before and acts weird.

Installed is a built valve body from BD, last fall, and it worked great so far.

Now I see very low line pressures all over the range except for WOT where it peaks out at about 160psi on my gauge - but on the computer (reading from the transducer) it stays well below 100psi.

At idle, vehicle stationary, Trans in D I see less then 30psi, raising maybe to around 50psi, more or less to the command from the ECM. Then the TC lock or 4th gear kicks in which is usually accompanied by a sharp pressure raise (command to 127) - but not anymore, pressure stays down like you see in the pictures.
From what I've read so far and from the documentation from BD I should see 85-90 at idle, stationary with Trans in D.

Also, when I let go the throttle (idle speed) the line pressure plummets immediately to below 60psi even at speed, TC locked.

Pictures are taken at 65mph interstate. One is constant speed, the other picture shows a WOT speed up and decrease which is the yellow line.

To me it is like that the electronic controls left the field and I'm stuck with just the regulation that the TV valve makes.

Fluid came new this summer, filters too, fluid level is perfect.

I'm at the end here as I can't figure out what's going on.


PS: What first pointed me to that I've a problem was when I was going downhill, EB on and it did an upshift to 4th gear which is totally unusual at 45mph.

 

[Ozymandias]

I would think that a faulty transducer wouldn't show any pressure at all?
Same for a faulty governor solenoid, I'd think it should be dead at all?
Why does command and return work at very low pressures?
Why does it command only 30psi at idle?

 

[Timd32]

Intresting stuff for sure.

@cerberusiam probably would be good at this one.

 

[Ozymandias]

Did a lot more reading through the night. I've two problems that maybe are interconnected. First is the low base line pressure. Even with the Trans relay pulled, means governor solenoid full open I don't see more then 45psi at idle, where it should be roughly 90psi.
Second - I don't get boost pressure at all, no pressure raise when it shift to 4th or lockup.
So I've a hydraulic problem rather then an electric one.

Which I hate...

Need to double check the readings of my gauge with an external secondary gauge.

 

[cerberusiam]

The last time I saw that problem it was a pressure leak in the upper part of the VB. Source another 48RE VB for rebuild and problem solved, sort of. When the next problem happened it went from working fine on the road to barely even moving when my son pulled off for fuel to completely quit moving when he got it to a motel parking lot across the street. Took out pretty much all the clutch packs with low pressure. From the looks of the marks on the VB to trans mating surface something is warped and it is bleeding off pressure. VB is definitely showing not true and possibly case also.

Might be as simple as replacing the transducer and gov solenoid but that was not my experience. We tested pressure before it completely quit and there were all in spec in all gears but it ate up the forward and direct clutch packs in less than 20k.

 

[Ozymandias]

Can't source avalve body here, I want to fix this one.

Did more test yesterday, had it idle in D and pulled the TV cable by hand - went up nicely to 150psi line pressure. So the pump is healthy, pressure and volume is there.
Throttle valve feels sticky and sometimes didn't want to move while pulling on it, loosened up somewhat while playing with it. Return spring at the lever is there.

Did a temporary fix by disconnecting the TV cable from the throttle lever and fixing it with a zip-tie to the throttle body at exactly 100psi idle, which needed roughly one inch of pull.
Making it a fixed valve body for now.
While driving I have now nice between 100 and 130 psi line pressure, Trans shifts nice through all gears and. Lockup comes a little later as usual but okay for now.
No unusual sounds or behavior so far.

Doesn't change that I still have no boost pressure which is probably the reason for the low line pressure - an open circuit at the top of the valve body. My guess is that it shot out the bracket for the spring of the boost valve and this is now lying in the pan.
That's my guess, I'll see it when I pull the pan.

 

[cerberusiam]

The sticky TV valves is the problem. That is usually wear in the bore and it is hanging when moving. Sonnax has a fix for it but it is obnoxiously expensive for the boring tool, but it is doable.

If you do not see a jump to about 180 psi when the OD is applied the boost valve retainer likely broke and allow it to eight spit it out all or most of the way.

 

[Ozymandias]

Thanks I check into this as soon as possible. For now the temporary fix will do. I'm on the Outerbanks NC and there is no place I can drop the pan or get a replacement part in time.

What ..... me is that this a just 13 month old VB from BD that I dropped in just 10k miles ago. I really expected more then this.
I'm in contact with BD customer service right now but do not expect much. Maybe they send me another one as replacement but not at this point right now in conversation.

 

[cerberusiam]

Yep, too many issues been reported with BD and their quality control.

 

[Ozymandias]

Yep, too many issues been reported with BD and their quality control.

I was looking around a year ago but two things guided me to BD then.
First was availability, second was the price I confess. Everyone else from the big players wants double the price of BD or even more. That is run a BD converter for ten years also helped with the decision.

 

[Ozymandias]

Have you ever used the "Superior" Retainer? That looks much more beefy to me.

 

[cerberusiam]

If you are talking about the boost valve, yes. Use that or a better than stock on every VB we build.

 

[Ozymandias]

If you are talking about the boost valve, yes. Use that or a better than stock on every VB we build.

Thanks, I'll do that.
Yes I stumbled over that retainer while doing my "homework" for that topic and thought it looks really good and solid.

 

[06 Dodge]

Sorry to hear your having problems, the only person I ever trusted for any 48 re part or rebuilds was, not sure all what they do now day: https://goerend.com/

 

[Ozymandias]

Sorry to hear your having problems, the only person I ever trusted for any 48 re part or rebuilds was, not sure all what they do now day: https://goerend.com/

Ja, that would be nice.
To get them or their installers to work on a truck is as hard as to catch a unicorn. In general it seems that everyone credible is overwhelmed with work and talks about 6-12 weeks on the wait list. That's not working out for me. If I need a mechanic I need it now as this is my home and I'm in a schedule.

 

[cerberusiam]

The closest to NC I know of that is good is Tim Barber at Industrial Diesel in Norfolk.

 

[Ozymandias]

This? https://industrialdiesel.com/

 

[cerberusiam]

I believe that is where Tim Barber ended up at after the COVID debacle. He was TRE Diesel Motorsports in Virginia Beach but is now supposedly out of Industrial Diesel.

 

[Ozymandias]

I ask because their HP says nothing about Transmission work.

 

[cerberusiam]

There was a discussion on CF about Tim and where he ended up, just have to call and see if he is still working out of there or moved on.