Driveline 48re vibration

[SlvrSnake]

I have had 1.5 inch Ground Force drop shackles on for about 2 yrs and recently have been noticing a driveline vibration that was never there before. As a result I noticed the tail-shaft seal was leaking in addition to this. Took truck in and the TC converter was replaced b/c of a shudder the tech noticed, new drive shaft and carrier bearing, and of course tail-shaft seal replaced. When he took the old drive-shaft off he noticed the rear most u-joint was tore up and I believe the carrier bearing was tore up. Not sure if he was referring to something in trans on this though.

Got it back and still has the same slight vibration/shudder it did as before I took it in. Tail-shaft seal is still leaking (Nice...). Tech said the driveline angle (overall output angle, I assume) was 5 degrees. Suggested I get the shackles off and put the stock ones back on. I checked the angles and got 2 degrees from every point to measure, tail-shaft, diff, and carrier bearing. I believe that would make it zero. It is my understanding that the angle should be 3 degrees overall. (Separate issue, but how to you change this?)

Anyway, my question is since I never noticed a vibration like this for the past two years these shackles have been on, could this be coming from the trans? I.e. Output shaft or something like that. The reason I ask is because the tail-shaft seal is wet again already after driving the damn thing like 50 miles. I am curious if this could be the real culprit. This is driving me nuts and I am really getting tired of the trans problems with these autos. I am sorry for the long post but this truck is really starting to piss me off and I want to get this shit fixed and not fear something breaking every couple thousand miles or less.

Thanks for any input.

 

[Yellow venom]

Is the vibration under heavy acceleration? At a steady rpm? Does it go away when you let off the throttle?
And the drop shackles will have no effect on vibration, I have 2" drop shackles for 3 yrs or so now and zero vibration, if they did cause a vibration you should have notice it right after you put them in not 2yrs later!

 

[SlvrSnake]

It starts around 40 mph and seems most noticeable at around 60 mph on smooth roads. Is more noticeable under light acceleration rather than heavy. If you drive it down a road with slight imperfections it feels like the rear end is on a razors edge (best way I can describe it, unsettled would be another term I would use). My old man order some blocks for the rear to change the angle on the rear diff but for some reason I feel it may be something else.

If you let off the gas you don't feel it as much but still present.

This is not a major vibration here. It is a slight shudder. The wheels have been balanced twice and rotated to eliminate that. Forgot to add that the first time.

I agreee with the shackles part. Would have been immediate. I don't want to waste my time taking the shackles off when I don't really feel they are the culprit.

 

[Yellow venom]

when was ur last tranny service? and what tranny fluid used? and have you changed oil in your rear dif?

 

[SlvrSnake]

Tranny has been taken apart about every 8k thousand miles since I have owned the thing, guess you could consider that being serviced. Was replaced with a rebuilt at 14K. Diff fluid was changed at 15K. Truck has 30k on it now. I was going to replace the diff fluid again this weekend just to see if it made a difference. Mopar ATF-4 has been used in trans.

 

[Yellow venom]

I would do a diff service on it and add that additive and see if that gets rid of it?
Im almost thinking u have a bearing in your tranny starting and theres a little bit of play in the rear bearing taking out the tail seal.

 

[SlvrSnake]

You and I are thinking along the same lines here. We'll see what happens. The tailshaft seal leaking again immediately made me think something was out of round. I hope it is just a bearing and not something more.

Thanks for taking the time to think about it and give me your thoughts. It is much appreciated. I will let u know what happens when I get a chance to change the diff fluid again.

 

[Troy's QC SRT]

have they checked your driveshaft balance?

 

[Yellow venom]

Sounds good,good luck on getting it right.

 

[SlvrSnake]

have they checked your driveshaft balance?

They replaced the entire driveshaft, carrier bearing and all. Sympton is still the same as it was with the old driveshaft, so I would rule the driveshaft balance out on that one.

 

[phxpoolguy]

Bent output shaft was the culprit in mine, fixed it this past weekend. Fairly easy to check but you have to drop that rear overdrive section, remove the clutches and spin it, had a bad bearing also, I would recommend replacing both bearings. Had the tranny rebuilt and this is something they normally don't check for is what I hear.

 

[Yellow venom]

Bent output shaft was the culprit in mine, fixed it this past weekend. Fairly easy to check but you have to drop that rear overdrive section, remove the clutches and spin it, had a bad bearing also, I would recommend replacing both bearings. Had the tranny rebuilt and this is something they normally don't check for is what I hear.

That would for sure do it!

 

[SlvrSnake]

Bent output shaft was the culprit in mine, fixed it this past weekend. Fairly easy to check but you have to drop that rear overdrive section, remove the clutches and spin it, had a bad bearing also, I would recommend replacing both bearings. Had the tranny rebuilt and this is something they normally don't check for is what I hear.

I honestly feel this is where the problem is myself, the trans. I guess you are refering to the front and rear output bearings. It really makes the most sense in my mind. We'll see. Good thing I bought the extend warranty. When that runs out I will probably get a built transmission from HTS and be done with all this BS if (sorry, when) it breaks again.

 

[Yellow venom]

I honestly feel this is where the problem is myself, the trans. I guess you are refering to the front and rear output bearings. It really makes the most sense in my mind. We'll see. Good thing I bought the extend warranty. When that runs out I will probably get a built transmission from HTS and be done with all this BS if (sorry, when) it breaks again.

If you were to buy the parts from HTS like I did would your dealership put them in and cover the install through the warranty??:dontknow:

 

[Troy's QC SRT]

When mine goes out I plan on going with an HTS as well but I hope by then we have a 4l80E options by then.....

 

[Yellow venom]

When mine goes out I plan on going with an HTS as well but I hope by then we have a 4l80E options by then.....

Good plan,my HTS parts are holding up perfectly,I had a tranny service done at the end of the year last fall after I beat on that tranny all summer and the oil was still like that day I put it in and no change in smell or colour,when he double checked the bands he said they were exactly where they were when he installed the parts meaning zero wear on the bands!!:rock:

 

[SlvrSnake]

If you were to buy the parts from HTS like I did would your dealership put them in and cover the install through the warranty??:dontknow:

Yes, I have the valve body, heavy duty band, 4.2 lever and billet accumulator from Dusty. I bought the parts about the same time you did. The thing shifts like a champ.

I guess I could see what could be done with Dusty. I would have to be sure before I ordered and that means truck at dealership for a long time, again. Those billet shafts are not cheap.