Any 47RH Transmission Experts? CTD Ram

JHZR2

Staff member
Messages
44,269
Location
New Jersey
Thread starter
Any experts on the 47RH on the "new style" Ram Cummins Turbo Diesel trucks - specifically a 1994 in this case. Happened upon one for sale with low mileage, pretty clean, no rust, pretty nice. But the owner is upfront about the AT - that it needs a bit of time to warm up and then it shifts fine, but when cold it will I've off the line to start, but will "drop out of gear" after a little bit of travel if not warmed up. Sounds like what I understand to be the loose band issue with these transmissions, but not entirely clear. I think the deal is good enough to consider an AT replacement, but that said, I'm hoping that I can learn and diagnose enough to determine if some other fixes might be sufficient for lighter-duty work. I love diesels, own diesels, but most of my use would be hauling heavy payloads, not trailering, and primarily flat ground. So hoping to learn! Thanks!
 
Messages
4,615
Location
Fort Worth, Texas
Need to make sure the ATF level is correct. These require the shifter to be in neutral as the torque converter does not fill in park. It's amazing how many Dodge owners don't know this. The Front (2nd) Band & Rear (Reverse) Band need periodical adjustment. The 47RH is notorious for Converter Drainback....... *Place the shifter in Neutral for @ 30 seconds to a Minute, If the symptoms disappear, The Converter is draining back. *When you park it for the night, Pinch off one of the cooler lines (Rubber portion), If the symptoms disappear, The drainback issue is in the Valve Body.....If it's persist....The issue is in the Pump (Worn Stator Bushings, Converter Hub Bushing, Or worn Pump Gears/Pump Housing. ****Un Pinch the cooler line before you test drive it**** grin2
 

JHZR2

Staff member
Messages
44,269
Location
New Jersey
Thread starter
Thanks, this is helpful. Will investigate later this week when I have time. The best I have is that the truck starts great, put it into drive, and you can get to the end of the driveway, but then it doesn't want to go. Let it sit and idle for 20 minutes and then it will go just fine and shifts well. Owner thinks it's the pump but just on gut feel. I've read a bunch about the bands on these... Truck is low mileage, but probably in a range where an AT rebuild isnt unheard of.
 
Messages
4,615
Location
Fort Worth, Texas
The front band just does 2nd gear (Holds the Direct Clutch Drum) & The rear band does Reverse & Manual Lo engine braking by holding the Reaction Carrier/Reverse Drum. I highly doubt a Band or Band adjustments is the issue here as they don't correct themselves with temperature. You'll probably find the fluid level a few quarts low when checked properly. Cooler lines rubbing together & developing pinhole leaks is very common on CTD powered trucks, But they will only leak in ranges other than Park.
 

JHZR2

Staff member
Messages
44,269
Location
New Jersey
Thread starter
Originally Posted by clinebarger
I highly doubt a Band or Band adjustments is the issue here as they don't correct themselves with temperature. You'll probably find the fluid level a few quarts low when checked properly.
Wouldnt it be funny if that is all that the issue is? The truck is very low use, owner has had it over 20 years and the mileage is low, they have a few other trucks as well... Ive read about how the valve body doesnt pump in park, and how the suncoast and a few others do. Of course Id probably change the valve body out even if it is just low fluid... And I do re-baseline ALL fluids when I get a new vehicle, so that would all be reasonable. Looking forward to investigating!
 

JHZR2

Staff member
Messages
44,269
Location
New Jersey
Thread starter
So, had a chance to drive the truck today.

ATF is nice and red. Was full in park.

Coolant and oil good. Hoses hard and crackly when I squeezed them. Oil is less sooty than my old MB IDI diesels.

Truck was cold when we started it. Started instantly, granted its 85+ degrees out. Sounded fine. Slightest whisps of white smoke, barely noticeable, but the injectors can probably use pop and balance.

The truck reversed and went forward without a hitch. 1-2 shift was soft, barely noticeable. 2-3 shift was slightly more obvious. Didn’t slip or slam.

Owner drove it to try to actually replicate issue - couldn’t do it. Only once did we get it to happen, rolling slow, gave hard throttle and it revved and then kind of slammed into gear. One shift felt a bit like a flare but was hard to say that’s truly the case.

He said it’s worse in the winter, and since it’s hot out that must be why.

Thoughts on that shifting issue?

thanks!
 

JHZR2

Staff member
Messages
44,269
Location
New Jersey
Thread starter
It must be checked in Neutral.
Yes, understand. The fact that it was full in park tells me that it might not be in neutral.

I wasn’t really in a good position to do troubleshooting, and kind of didn’t want to in front of the seller.

was hoping to gain further insight into what it means when it feels like the engine starts to rev up and then it sort of slams into gear.
 
Messages
4,615
Location
Fort Worth, Texas
Checking the ATF level & correcting if necessary is the first step to diagnosing any automatic transmission issue, Especially with a all hydraulic unit like the 47RH even though the 3-4 shift & TCC is controlled via solenoids.

I understand not wanting to "fix" the truck during a purchase negotiation though, Good luck.....I've owned two 2nd Gen 12 Valve CTD Rams & they're good trucks!
 
Messages
16,357
Location
NH
Sounds like it is worth the risk--as you said, you are ok with replacing, and by the sounds of it, it's not doing this problem all the time.
 
Messages
2
The inner seals on the direct and toward clutches are old hard and shrunk. New replacement lip seals are way better and larger. Seals have a hard time sealing properly when cold. I work on these a lot for hot rod diesel guys. If that is the only problem buy it. Those transmission are easy to build and hold big power. The 47rh has gotten a bad rap. You can make that trans hold up with a little guidance.
 
Last edited:
Top