are 47re autos weak?

-
R

rustycowll69

Well-Known Member
Joined
Feb 19, 2016
Messages
2,747
Reaction score
1,475
Location
Pacific northwest
47re's are mostly just 3spd 727, with an extra planetary hung off the back of the case, right? So why do they have the reputation as being weak? I mean I don't remember people complaining about weakness when 727's were behind 440's, or Hemi's, which weren't slouches. So why are the 47re's considered weak behind 5.9L magnums, or the v10's? please be as specific as possible.
 
I'm not sure actual 47's WERE used behind magnums. The number indicates power level, so 46 is lower power level than 47 or 48. V10 and Cummins output a LOT of torque are installed in VERY heavy vehicles designed to tow and carry heavy loads. So right out of the gate they see heavy use. Maybe "Ma" should have put allisons in them...........or just stood firm and insisted people learn to drive 5 speeds.

And people can tear up a lot of hardware from ignorance, too

And they aren't just a "727." 727's had many power levels and WERE different between 318 or hemi and changed over the years. A parallel might be applied to the "lowly" Powerglide. When I was a kid I wouldn't give you 3 bucks for a damn Powerglide, yet today, built with heavy duty aftermarket parts, they are drag raced with tremdendous power, over 1000hp in some cars
 
I have a 47RE in my ‘02 cummins 2500. The transmission is the biggest pile of ****. One day if I ever get the money, I’ll do a 6 speed swap. NV5600. That is all I have to say.
 
I'll give you one specific reason; because they're built like small block 727s, not big block; with only three direct frictions. Add the overdrive, and you're going back and forth into and out of third gear three times as often as before when it was a three speed.
 
The biggest thing that killed that transmission is the stupid check valve that Chrysler put in the cooler line. It's know to get clogged with crap and cook hard parts. That transmission will go until is smokes itself without the lube circuit from the cooler. First thing we always do when we have one in the shop is take that check valve out and installed a Transgo shift kit. It has a longer shoulder on the manual valve so the torque converter will not drain back when the vehicle sits for a few days. That was the only reason that check valve was added.
 
I really don't think they are a POS like previously stated. they are built for the power level of the engine in front of them. That said especially the diesels are very easy to bump up the power and then the trany fails and its a POS. also mid 90's automatics the lockup in the converter were basically paper clutches that was a problem that if overheated the "clutch" material would start coming apart and get in the fluid lines and valvebody and then the failures began. Also now days 100k on a vehicle is low millage but in the 60's few of them made it to 100k before being scraped.
 
Stock 47re has (4) frictions in the forward clutch pack. You can upgrade them to 5 if you really want to.
 
Hellrats said:
The biggest thing that killed that transmission is the stupid check valve that Chrysler put in the cooler line. It's know to get clogged with crap and cook hard parts. That transmission will go until is smokes itself without the lube circuit from the cooler. First thing we always do when we have one in the shop is take that check valve out and installed a Transgo shift kit. It has a longer shoulder on the manual valve so the torque converter will not drain back when the vehicle sits for a few days. That was the only reason that check valve was added.
Click to expand...
so whereabouts is this check valve, so I can remove it?
 
Up in one of the cooling lines at the radiator where the steel connects to the rubber.

check valve.jpg
 
256,000 miles on mine. Have not had any problems or updated anything. It has always been used to haul everything from farm animals to campers. Removed the check valve and added the shift kit. Don't haul with the OD turn on and service it. My diesel engine is bone stock. Maybe I'm just lucky? IDK
 
Hellrats said:
256,000 miles on mine. Have not had any problems or updated anything. It has always been used to haul everything from farm animals to campers. Removed the check valve and added the shift kit. Don't haul with the OD turn on and service it. My diesel engine is bone stock. Maybe I'm just lucky? IDK
Click to expand...
maybe some of these Cummins people, who are unhappy with their 47re's, have modded their engines(which I understand is quite easy to do) beyond what their oem trans is capable of handling without being modded, too.
 
I have drilled them out before but it's a PITA. I just cut the steel line and flair it and replaced the rubber hose. You could unbolt it and get fittings if you want to get fancy but I just clamp it. Just like they did on your old A and B bodies from the factory. It's not high pressure.
 
My 01 Cummins made 329,000 kilometres b4 I rebuilt the tranny. The lock up clutch was slipping in the torque converter when pulling. So I then went thru the tranny. I pulled everything in overdrive. Kim
 
rustycowll69 said:
maybe some of these Cummins people, who are unhappy with their 47re's, have modded their engines(which I understand is quite easy to do) beyond what their oem trans is capable of handling without being modified, too.
Click to expand...
Truer words for sure. Double the HP and torque, which is quite easy to do in a diesel, and forget to upgrade the transmission=lots of broken transmissions. This is true also with the GM Alison transmission, and the Ford Diesel transmission. The company I worked for in the past, makes hard core parts for these transmissions. They have a hard time keeping up with the orders.
 
I've owned 95 CTD. a 2003,2004.2007 I have never had to rebuild a auto. 385k on the 95, 285k on the 07. I've towed 40' fifth wheels, car trailers open and closed. And many other trailers. I have never modded the engines. May be a connection?
 
Hellrats said:
I have drilled them out before but it's a PITA. I just cut the steel line and flair it and replaced the rubber hose. You could unbolt it and get fittings if you want to get fancy but I just clamp it. Just like they did on your old A and B bodies from the factory. It's not high pressure.
Click to expand...
Do you use high pressure line and double clamp them or what?
 
Cooler line pressure is about 25 to 35 psi. You can use the correct fluid type hose for ATF and clamp it.
 
Listen, I'm not here to tell you what to do I'm just telling you what has worked for me over the years. There is lots of stuff on Google. It's not a bad transmission and that is my opinion.
 
NewMy 01 Cummins made 329,000 kilometres b4 I rebuilt the tranny. The lock up clutch was slipping in the torque converter when pulling. So I then went thru the tranny. I pulled everything in overdrive. Kim

Well... that may have been the problem. Slipping is never good for any transmission. Getting out of lock up and OD when pulling anything is always a good idea.
 
You must log in or register to reply here.
-

Back
Top