48RE growl or grind on final shift.

[Ken F]

I know I have read a discussion on this subject, but I was not able to find it in a search.



As you can see in my signature, I have an ’03 HO with a 48RE. I just got back from a 600 mile trip pulling a travel trailer that weighs around 9000 pounds fully loaded. I have been experiencing a growling or grinding noise on the final shift. I believe this is when the converter locks. It appears to be on the passenger side near the front of the floor board. (turbo area) It happened 5 or 6 times during the 4 day trip. This usually occurs when I am being light on the go pedal, but not always. It did happen one time during a ½ to ¾ throttle acceleration. (un-loaded)



If I remember correctly, the discussion here suggested that this is turbo related and it is caused by the sudden and substantial RPM drop caused by the final lock up of the converter.



How common is this? Is it anything to be concerned about?



All feedback is appreciated.



Ken.



P. S. On another note, I must say I am really impressed with the overall performance of this truck. This is my first Dodge. I have had two Powerstrokes and was never truly happy with either one.

 

[Blufrog]

My truck does this sometimes as well when I am towing my trailer and it only weighs about 7k loaded. I am not sure if it is just all the torque at low RPM kicking in or what but it feels like the transmission is going to drop from under the truck in pieces.

 

[JThiessen]

Same here. I tow in the range of @8500lbs.



Ken described it almost perfectly. Mine didnt start doing it until this year, and only after/while towing. In fact the first time was on a drive, while empty, the day after towing. I've been worrying that this is the result of the new exhaust system, or possibly my pulling the transmission test port plugs when attempting to find a location for my transmission tmep guage.



There is something most definitley wrong with transmission for it to make that noise - just wish I could figure out how to duplicate it for the dealer without having to take him on a 3 hour drive through the mountains.

 

[nwjetboat]

I believe what you are hearing is "Turbo Bark". It is caused by the large drop in rpm when the converter locks up into overdrive.

I actually made mine a touch worse by installing AFE filter and Torque Tube. At least the sound is more pronounced. My solution is to leave the transmission in O/D off or Tow/Haul mode until I get to 55-60mph on the flat or when I feel I am backing out of the throttle to maintain speed.

From what I have read, you can snap the turbo shaft by "barking the turbo". .

As this is my first diesel, maybe some more experienced TDR folks will chime in with more info. .

 

[JARichard]

Mine does it to and kinda jumps a little. Are you guys sure it is the TURBO and not the Torque converter. If you are RIGHT that is a big weight off my shoulder. I thought the converter was going OUT.

 

[FJfonda]

Mine did it after 300 miles of non stop towing 12,000 lbs. Most of the trip was at 65mph and we took a slower detour that kept the speeds at 50-55. Going through one of the smaller towns I had slowed to 45-50, left it in OD and when it upshifted it made the noise you described. It did it once more before I wised up and took it out of OD..... didn't do it again. It has never done it unloaded (7500miles) but occasionally the upshift is a little abrupt. I was thinking that with the trailer... . the occasional abrupt upshift is actually causing TC shudder. Ideas???

 

[Rineholio]

Mine does it too. A mechanic type told me they all did. Mine has done it since new, but it was pretty unnoticable until I installed a 4" exhaust. Therefore I think it's related to the turbo... If it makes you feel any better, I think mine would have gone by now if it was going to. About 13000 miles, half of it towing 10-11k toyhauler through mountains, desert...

 

[Rosco]

I tow a 10,000 pound fifth wheel and I have noticed the same thing. I don't understand why the computer is programmed to shift into overdrive and lock the TC at the same time. I would think a shift into OD followed by the TC locking a short time later would reduce how abruptly the rpm's get pulled down.

 

[Ken F]

It's getting worse.

I just got back from another trip pulling the same load. This was only happening periodically. Now it is happening nearly everytime on the final shift. And sometimes it makes 2 or 3 grinding noises, where as it used to only do it once.



I have not taken it to the dealer because I suspect they would just blame it on my exhaust. (I have the 4" Banks)



Is mine the only one that is getting worse?



Ken.

 

[yycguy]

Well my truck does the same and as with one of the other posters it seemed to happen more after installing the 4" exhaust. But as others have posted just keep it in Tow/Haul until the 55-60 then let off on the throttle hit OD and then back on the pedal. At least that works for me and it shifts really nice that way. btw I only really have to do this when towing

 

[Ken F]

I understand the OD button trick. I started doing that on this last trip. But there was still one time when I was in a contruction zone and my speed dropped. I wasn't thinking about it and as my speed crept up, all of the sudden there was the big grind.



Also, it happen three times today while un-loaded. It is getting worse.



If all trucks don't do it, then what is different on the ones that don't.

 

[jcarey]

If you got the sound under slow acceleration, it's definitely not turbo bark. We have an 04. 5 with the AFE Prgguard 7 (see sig). I hear the whistle as the turbo builds boost, but have not had any grinding or other kind of noise during accel or decel. Turbo bark only happens under sudden decel.



Jim

 

[Ken F]

I wouldn't call it slow acceleration, but I wasn't hammering it either. It happened on the final shift, when the engine has about a 600 RPM drop.

 

[WRStrong]

I posted with this same concern about a year ago. Got some pretty interesting feedback. :-laf The most reasonable one suggested that the torque converter clutches were shuddering upon lockup under a moderate pull. I definitely feel like it's a transmission thing. Mine doesn't do it so much any more because I let off just before it shifts into OD.



BTW, my 48RE locks up usually long before shifting into OD. The lock up in 3rd gear is almost like shifting to another gear. I think part of the problem is the huge drop in RPMs between 3rd gear and OD. too bad there isn't another gear in between to bridge the big change in RPMs.

 

[JMusso]

KenF you described exacty what happens to me when towing. I have been leaving it in tow/haul mode when I take off from a stop and then flip off the t/h mode when I get to about 55 like YYCGUY said and it seems to work.

 

[FJfonda]

Flash 18-037-04 helped????

I had the 18-037-04 flash done for improved milage and noticed the 48RE shifting into 3rd and then the transiition to lockup is much smoother. In fact, I have not experienced the growl we discussed here since the reflash. Anyone else have the same experience?

 

[TCDiesel]

My 97"s had it ,So did the 01"s and now My 03 has it,The 97"s and the 01"s were V-10"s With the 47re"s the 03 is 47re upgraded to ATS stage IV, it is diffidently transmission related , they all ran 50k plus ,I just think it is a inherent noise,I just turn the radio louder,it seem to be a good fix.