Engine Code in Chit...

[Johann]

Had P0750 pop up while on a trip. It tossed the transmission into "limp mode" which was fun. Kept the speed down and watched the temps the whole time home.

Not finding a whole lot on Ram centric forums but they are mostly Bolt On people and "take it to the dealer" is the answer. I'll take it to a local trans shop 5 min way for diagnostics before I go that far!

Narrowed down to:

L/R SOLENOID CONTROL CIRCUIT OPEN
L/R SOLENOID CONTROL CIRCUIT SHORT TO GROUND
L/R SOLENOID CONTROL CIRCUIT SHORT TO VOLTAGE
TRANSMISSION SOLENOID/PRESSURE SWITCH ASSEMBLY
POWERTRAIN CONTROL MODULE

From here- https://ricksfreeautorepairadvice.com/dodge-ram-doesnt-shift-p0750/ but the PCM he gives diagnostic info on has 4 connectors on it and mine has two so I have not been able to figure out which pins to check resistance on.

I have pulled the connectors off the PCM and the Trans. Both were clean. Trans one had the slide lock loose and I hoped that the energetic car wash I had before the trip might have soaked one but they were dry. Would have been appropriate since I broke my usual rule of never wash the truck!

I have not yet checked continuity for the same reason above. Not sure what pins go where- both ends are different shape. I can chase it down by color but it it probably the least likely culprit. Harness visually looks good.

The other two usual suspects are an internal fault in the PCM or bad Solenoid in the bank above the valve body. I've done both of these jobs on other trucks so I can do it on this one provided I can figure out which one has failed. Rather not do both as at least one thread on Ram Forumz ended up doing... Also much rather swap in a referbed PCM than crawl under and crack the trans open on a creeper too!

This is making me miss my manual trans...

This is for a Ram 1500 5.7 Bighorn. 4X4 65RFE 6 spd trans.

TLDR: Anyone been through this one before? Anything to look out for?

 

[TrikeKid]

Last one I had with that code needed a solenoid pack. Have to drop the valve body to replace it.

 

[Johann]

Last one I had with that code needed a solenoid pack. Have to drop the valve body to replace it.

Was that the first thing you tried or did you diagnose it further than I have so far?

Any specialized tools or tricks needed to pull the valve body? I've looked at a R&R descriptions and it looks pretty standard.

 

[TrikeKid]

Was that the first thing you tried or did you diagnose it further than I have so far?

Any specialized tools or tricks needed to pull the valve body? I've looked at a R&R descriptions and it looks pretty standard.

Checked continuity across the solenoid and it was NFG in that case. Valve body doesn't require anything special other than you'll need an inch pound torque wrench that reads real low, solenoid body to valve body bolts are only 50 in/lb.

 

[TRINDU]

Last one I had with that code needed a solenoid pack. Have to drop the valve body to replace it.

Yep. Not that big of a deal, afternoon on your back in the driveway.

Its not individual solenoids like a AW4, but a pack/unit. Probably $150-200 depending where you shop.

pack is bottom left, valve body below it.

 

[Johann]

Checked continuity across the solenoid and it was NFG in that case. Valve body doesn't require anything special other than you'll need an inch pound torque wrench that reads real low, solenoid body to valve body bolts are only 50 in/lb.

Did you check it in place? That connector is in a PITA spot behind the drive shaft and some other junk. It would be handy to have a pig tail to connect to it. My head doesn't fit in there!

Thanks for the heads up on the in/lb TR. Fortunately I have one.

 

[xr-nut]

Its a dodge transmission. it needs the solenoid pack. order it then put it in. hopefully you have a dipstick in the tube? thats another dodge thing, put the tube there but no dipstick(besides the one beyond the steering wheel) to check. /thread

 

[Johann]

Yep. Not that big of a deal, afternoon on your back in the driveway.

Its not individual solenoids like a AW4, but a pack/unit. Probably $150-200 depending where you shop.

pack is bottom left, valve body below it.

That is the first pic I have seen with the Valve Body attached to the Pack. That helps put it in context!

The Pack is $285 from the usual suspects. I've done a AW4 before. Wasn't too bad.

Nice thing about the truck is that it is tall enough that I can work on it without jacking it up.

 

[TrikeKid]

Did you check it in place? That connector is in a PITA spot behind the drive shaft and some other junk. It would be handy to have a pig tail to connect to it. My head doesn't fit in there!

Thanks for the heads up on the in/lb TR. Fortunately I have one.

Yes, and yes, it's a fucking whore to get to.

 

[Johann]

Yes, and yes, it's a fucking whore to get to.

Thanks for telling me!

 

[Johann]

Drove home from work last night and the code was magically turned off (Like all pesky engine codes do) after being on and in limp mode all the way TO work. Still had the P0750 code in memory though so I ended up taking it to a local Transmission shop in town. Seem like good guys. Into jeeps and offroading.

They ran a long diagnostic, drove it for 20 min and came back only recording:

"One very quick instance of fluid pressure drop in shift 2-3 With balance of shifts and performance within design spec. Suggest customer hold off on repairs till they return. Likely issue will be solenoid block."

Total cost estimate for R&R of Solenoid block...$1,100 before tax. Sooooo we know who will be doing this job in their driveway if it comes to it.

Interesting tidbit was that they said that if the issue is the PCM usually all shift points are affected and the truck will rev but not move well in all gears.

I was impressed that the shop did not try to pressure me into the repair. They will get more work from me, at least diagnostic. Can't tell you when the last time I actually had a shop repair something! But as vehicles get more electronics and black boxes things are getting harder to user service.

We will see how long I get to drive this before I need to do the repair. I am dusting off my old WJ for DD use and to have something to drive when it is down. Needed to drive that more anyway...