Vibration after Southbend Dual Disc Clutch installed

[Mopar1973Man]

One thing about someone doing a clutch I've got to ask did they force the transmission in place using bolts or did they get it fully seat before putting bolts in? 

 

This is a key point of most clutch and transmission failures. When its forced in place then thing tends to be out of alignment and possibly forced bearings into running with tension. 

[cuda]

You might ask about the rubber rivets that come with the new street DD clutches,  They are little rubber rivots that go sideways (not on the face or back) of the intermediate plate that sits between the clutches. There are 4 flat points that have little holes that the rubber goes in they keep the plate quiet. If they are installed then it can also be the normal noise that Duals are known for?

[CUMMINSDIESELPWR]

2 hours ago, Mopar1973Man said:

One thing about someone doing a clutch I've got to ask did they force the transmission in place using bolts or did they get it fully seat before putting bolts in? 

 

This is a key point of most clutch and transmission failures. When its forced in place then thing tends to be out of alignment and possibly forced bearings into running with tension. 

took me and a friend and a tranny jack 3 hours to get it perfectly aligned to slide in with minimal force....   holy crap that thing with tcase married is heavy as hell.  but we got it done right.

[LegendaryKing]

UPDATE!

My regular maintenance/repair mechanic is an obsessive compulsive perfectionist.  I drove my truck last week because he didn't like the "noise and vibration" he was getting from the trans.  It's actually quieter than when it was stock and has less vibration (almost zero) through the shifter.  It's actually a little on the disappointing side as it use to feel like a truck, and now the clutch/shifter/noise feels civilized.  I believe that is due to a proper install and a high quality clutch.  I wonder how much more mass/dampening you get from the twin-disc over a factory clutch?

 

I had a few other problems that are getting repaired but I have to wait my turn in line so hopefully the truck will be ready soon but at least I'm out of the woods. 

[CUMMINSDIESELPWR]

good to hear!

[LegendaryKing]

And I spoke too soon.  When the transmission is cold I get a grinding noise when shifting and the transmission ALWAYS grinds going into reverse.  As soon as you put a few miles on it the trans shifts into fwd gears without issue.  It has Redline MTL in it and my shop is telling me they think the syncros are toast and it might need a rebuild.

 

What do you guys think?

[Mopar1973Man]

Most likely the gear lube was too thin. Couldn't protect the synchros. With the dual disc clutch, there is a lot more mass spinning and the synchros have to sync the input and output speeds and since the fluid is then by factory specs and the added mass most likely ate the synchros.

 

The other possible problem is the dual disc is having issues and dragging the input a bit too much and causing the grind and shift problems. 

Edited May 3, 2019 by Mopar1973Man

[LegendaryKing]

34 minutes ago, Mopar1973Man said:

Most likely the gear lube was too thin. Couldn't protect the synchros. With the dual disc clutch, there is a lot more mass spinning and the synchros have to sync the input and output speeds and since the fluid is then by factory specs and the added mass most likely ate the synchros.

 

The other possible problem is the dual disc is having issues and dragging the input a bit too much and causing the grind and shift problems. 

 

Shop thought the same thing (thin fluid) and wanted to do a drain and refil to make sure the trans fluid was ok.  Did a drain a refil with Redline MTL.  The truck had Redline MTL in it before the drain and refil.  No change.   After a mile or two of driving all forward gears shift like butter. 

 

Is Redline MTL too thin?  If so what is the recommended fluid for a trans with dual disc?  Doing a fluid drain and refil is a lot easier than pulling the trans out again. 

[Mopar1973Man]

Personally, I think all of it is too thin. Even the factory fluids. When shift quality goes down people opt for thinner fluids then the wear sets in faster. Like I found out the factory 75w 85 for the NV4500 isn't enough and I ate the 5th gear hard facing off. The gear was replaced but it proved to me that factory fluids don't protect good enough. 

 

Thinner the fluid better the shift quality this why the dealer is now filling both NV4500 and NV5600 with ATF+4 just like the G56 transmission. Shift quality is great but the protection of the gears and parts is really poor. Pennzoil SyncroMech fluid is technically a GL-4 fluid but doesn't make the rating because it's too thin to make the full GL-4 rating. Again here we are with thin fluids. The gearbox is going to generate heat the fluid has to protect the gears and bearing. If the heat gets too much the fluid gets to thin and it starts creating wear.

 

Kind of like why we don't run 0w 20 engine oil it would get to thin to protect the moving parts of the engine. But it would have the least amount of drag and produce the most power. Same thing with a gearbox it needs to be thick enough to protect the parts and synchros. 

[LegendaryKing]

44 minutes ago, Mopar1973Man said:

Personally, I think all of it is too thin. Even the factory fluids. When shift quality goes down people opt for thinner fluids then the wear sets in faster. Like I found out the factory 75w 85 for the NV4500 isn't enough and I ate the 5th gear hard facing off. The gear was replaced but it proved to me that factory fluids don't protect good enough. 

 

Thinner the fluid better the shift quality this why the dealer is now filling both NV4500 and NV5600 with ATF+4 just like the G56 transmission. Shift quality is great but the protection of the gears and parts is really poor. Pennzoil SyncroMech fluid is technically a GL-4 fluid but doesn't make the rating because it's too thin to make the full GL-4 rating. Again here we are with thin fluids. The gearbox is going to generate heat the fluid has to protect the gears and bearing. If the heat gets too much the fluid gets to thin and it starts creating wear.

 

Kind of like why we don't run 0w 20 engine oil it would get to thin to protect the moving parts of the engine. But it would have the least amount of drag and produce the most power. Same thing with a gearbox it needs to be thick enough to protect the parts and synchros. 

 

So putting thicker oil in my transmission isn't going to improve my shifting problems, there is more than likely a mechanical problem with the transmission that needs to be diagnosed?  Thinner transmission fluid would make the transmission shift better, but will reduce the life expectancy and since I'm already running Redline MTL I'm at the thinnest I can go so time to start looking at hard parts and stop swapping fluids around?

[Mopar1973Man]

46 minutes ago, LegendaryKing said:

So putting thicker oil in my transmission isn't going to improve my shifting problems, there is more than likely a mechanical problem with the transmission that needs to be diagnosed?

Typically this what happens people swap to thinner fluids and gain a bit of time before it all goes bad. 

 

46 minutes ago, LegendaryKing said:

Thinner transmission fluid would make the transmission shift better, but will reduce the life expectancy and since I'm already running Redline MTL I'm at the thinnest I can go so time to start looking at hard parts and stop swapping fluids around?

Yeah, 6 speeds (NV5600) are not cheap to fix either. Nearly 2 times the price of a 5 speed (NV4500) to rebuild. Like mine was $1,800 to rebuild new bearing, synchros and 5th gear replaced, and a main shaft. The reason 6 speed is so expensive is not really many building parts and really kind of tough to get. 

Edited May 3, 2019 by Mopar1973Man

[Dieselfuture]

Could be something with the clutch too. Mine always shifted tough until it warmed up. 

[LegendaryKing]

Spoke with the good people at South bend and they gave me some diagnostics to run on the hydraulic system.  The test is found on their website.  If the link breaks it is under resources and is called Hydraulic Testing. 

 

According to South bend I'm running the exact fluid I should be (Redline MTL) and it is apparently normal for the dual disc to have issues going into reverse.  It is recommended to shift the transmission into 4th first, then reverse.  Seems hokey but at least it's expected.  South bend recommends AGAINST running thicker fluid as it has a high probability of pushing/blowing out transmission seals. 

 

In addition they believe my cold shifting problems in forward gears could stem from the hydraulics and I have one or a few problems.  1. installed wrong, 2. adjusted incorrectly, 3. bad and require warranty replacement.  The shop that installed the clutch correctly will be looking into the hydraulics (South bend hydraulics and installed by previous shop) in the next few days when they have time in the schedule.

 

I'll update this thread when I hear more, but I wouldn't be surprised if the hydraulics were installed incorrectly by the previous shop. 

 

 

Edited May 10, 2019 by LegendaryKing

[LegendaryKing]

Hydraulics passed the tests and the clutch is coming out of the truck.

[dripley]

Just to add, any 6 speed can be a bit difficult to go into reverse or first right off the lot. Putting it into 4th to get reverse is not abnormal. Still have to do it mine sometimes to this day. The dual disk from what I know just makes it a bit worse. The 5600 is a big tranny and a lot different from the 5 speed.

[LegendaryKing]

Update:

Transmission is out getting rebuilt.

 

Here is the lowdown:

Apparently the input shaft was damaged on the initial install and that damaged the pilot bearing and the throw out bearing.  Everything was so galled up it was difficult to get the bearings off the input shaft.

I'm told the Dual Disc looks clean and should be problem free.

The pilot bearing, throw out bearing (TOB), and input shaft are trashed.  Ordered all new parts from DAP. 

When the transmission came down, there were TONS of brass shavings around the shifter, in the fluid, etc.  Apparently the TOB wasn't releasing causing the input shaft to continue rotating and destroyed the syncros.

 

I hope this helps someone in the future because it has been an expensive HUGE pain in the ***.

 

[dripley]

That does suck. Is the installer helping with any of this?

 

Who do you have building the tranny?

[LegendaryKing]

37 minutes ago, dripley said:

That does suck. Is the installer helping with any of this?

 

Who do you have building the tranny?

 

The installer is pulling and re-installing the transmission.  We have a good relationship as I have known them for 25+ years.  This is not their fault; this is all due to the original installer royally screwing up a clutch replacement job.

 

The original installer who caused all of these issues from the beginning is unavailable for comment.

 

The installer sent the trans out to a local guy that apparently knows this transmission inside and out.  It comes with a 2 year unlimited mileage warranty.  As I said, I trust THIS installer as I have known them for years, if they say the re-builder is good I believe them.

 

I'll update once I get my truck back.  Hopefully my shoulder/arm/back will be healed up shortly so I can drive a stick shift.  I was rear-ended in the wife's crossover suv and my arm is in a sling.  The good news just keeps rolling in doesn't it? 

[dripley]

Good you have someone to trust. Sounds like you might have time to heal too.

[Mopar1973Man]

On 6/2/2019 at 12:03 PM, LegendaryKing said:

Hopefully my shoulder/arm/back will be healed up shortly so I can drive a stick shift.  I was rear-ended in the wife's crossover suv and my arm is in a sling.

Man that sucks... Now you got the arm issues, the wrecked SUV and your truck out of action. Take a deep breathe and work your way through it.