2005 new to me 6 speed trouble

[AH64ID]

What happened to its not compatible with 5600 synchronizers. That was the statement of fact you made that I questioned.

Nothing happened with it... If you don't like it do your own research.

You are only postings info about fluid not rated for a NV5600.

 

[jhenderson]

I asked because you made a declarative statement about synchro wear with Mobil 50. I did the research, listed the Mobil fluid you referred to and then compared it to Mobil 50. I also told you of Mobil's claim of it being safe for all yellow metal synchros. I'm waiting for your explaination of supplying false info to the other members. I bring this all up because bad info is often worse than none at all and we should all exercise caution when giving advise without direct knowledge. Whether any particular fluid is factory recommended is irrelevant, when one makes a declarative statement that is factually incorrect.

 

[ELK311]

93k on my NV5600 and clutch is on its way out. I tow a 5k RV only a few times a year otherwise its a commuter and I have certainly towed in 6th gear :-( I did not know that you shouldn't. I also downshift a lot and was recently told not to do that with new diesels and transmissions...??? So I have been using more brakes vice downshifting. I also have a Jacobs brake that is used almost all the time.

Sounds like my clutch is failing early, any of the things above that I am doing wrong?

Thanks for any advice.

Garth

 

[jhenderson]

You aren't doing anything wrong. The stock clutch is just barely adequate for the job. I ran an exhaust brake on my 04 for 398,000 miles, driving just as you describe. 2 quarts over full on the trans and never a transmission problem. Most of my clutch trouble came from the release bearing drying out and coming apart, 3 times. Being hydraulic they're always in contact with the persuade plate and have no means of lubrication.That's most likely due to a 15 hr residential snow plow route. A little glazing from traffic, maybe a little contamination or a hung release bearing is all it takes to slip under the right conditions. I'd recommend talking to Peter at South Bend for a slight upgrade. Be sure to get a new pilot bearing at the same time. My 2 cents.

 

[Tuesdak]

Select the proper gear for the conditions IMO what you have been doing is ok. Flat, no wind, no hills 6th is fine. You have a feel for your truck and know that even without lugging there is a limit of what you should push power-wise through 6th. As soon as you hit a hill do drop it down a gear. Downshift when you like after all automatics shift when they need to. Every shift does take some life from things, but, wear items they are and thus "So What!?"

Stripping the teeth from 6th gear from lugging it too much is more of a concern than extra clutch wear from shifting often. Nothing wrong with winding the engine RPM up and leaving it there. This isn't a gas engine and won't blow up from sitting just under red line all day. More water pump RPM, more oil flow, more cooling fan RPM available when towing. Sure shift to 6 for economy when it makes sense, but, do not be afraid to wind it up on less than 1/2 throttle for a grade.

Best advice is to keep your foot off the clutch at stoplights.

Downshifting to slow down and using the Jake all the time is not as good of an idea. Use it when towing of course. Exercise the Jake at least once a month, but, constant DD use you are trading brake wear for clutch and transmission wear. Note clutches are designed to torque in one direction only so Jake Brakes do take life off them. Downshifting to slow down as a DD is just wasting the clutch (transmission, syncros, etc) when you could just burn off the long life, cheaper, and easier to replace brake pads instead.

 

[jhenderson]

Everyone's entitled to their opinion but I never turned off my EB in 398,000 miles except for icy roads. Never failed a clutch, just release bearings and never opened the NV 5600. I also towed 18,000lbs in sixth when conditions were right.

 

[Tuesdak]

Everyone's entitled to their opinion but I never turned off my EB in 398,000 miles except for icy roads. Never failed a clutch, just release bearings and never opened the NV 5600. I also towed 18,000lbs in sixth when conditions were right.

Glad you got good life from your stuff. However it's NOT an opinion. 2nd to the last question explains using the clutch as a brake and last time I spoke to Standard Transmission they had some unlucky SOB's NV5600 in the shop that didn't last under Jake Brake use.

http://www.southbendclutch.com/troubleshooting.html

 

[NIsaacs]

Glad you got good life from your stuff. However it's NOT an opinion. 2nd to the last question explains using the clutch as a brake and last time I spoke to Standard Transmission they had some unlucky SOB's NV5600 in the shop that didn't last under Jake Brake use.

http://www.southbendclutch.com/troubleshooting.html

When you down shift and RPM match, the clutch is fine. What kills them is a down shift at idle. The Jake did not trash the NV5600, poor maintenance, high mileage and or non skilled driver did.

Nick

 

[photowrite]

Select the proper gear for the conditions IMO what you have been doing is ok. Flat, no wind, no hills 6th is fine. You have a feel for your truck and know that even without lugging there is a limit of what you should push power-wise through 6th. As soon as you hit a hill do drop it down a gear. Downshift when you like after all automatics shift when they need to. Every shift does take some life from things, but, wear items they are and thus "So What!?"

Stripping the teeth from 6th gear from lugging it too much is more of a concern than extra clutch wear from shifting often. Nothing wrong with winding the engine RPM up and leaving it there. This isn't a gas engine and won't blow up from sitting just under red line all day. More water pump RPM, more oil flow, more cooling fan RPM available when towing. Sure shift to 6 for economy when it makes sense, but, do not be afraid to wind it up on less than 1/2 throttle for a grade.

Best advice is to keep your foot off the clutch at stoplights.

Downshifting to slow down and using the Jake all the time is not as good of an idea. Use it when towing of course. Exercise the Jake at least once a month, but, constant DD use you are trading brake wear for clutch and transmission wear. Note clutches are designed to torque in one direction only so Jake Brakes do take life off them. Downshifting to slow down as a DD is just wasting the clutch (transmission, syncros, etc) when you could just burn off the long life, cheaper, and easier to replace brake pads instead.

A very good post with lots of good tips and reminders.

 

[photowrite]

When you down shift and RPM match, the clutch is fine. What kills them is a down shift at idle. The Jake did not trash the NV5600, poor maintenance, high mileage and or non skilled driver did.

Nick

Also a good comment/observation.

 

[South Bend Clutch]

JDoremire would you like a job manning our phones? LOL You are spot on!!

Peter

 

[seafish]

When you down shift and RPM match, the clutch is fine. What kills them is a down shift at idle. The Jake did not trash the NV5600, poor maintenance, high mileage and or non skilled driver did.

Nick

In my understanding, using an exhaust brake in some circumstances will put the same "reverse" stress on a clutch disc as improperly downshifting.

 

[lpennock]

@South Bend Clutch

I'm having trouble understanding how engine braking is any harder on a clutch than acceleration. In general the torque to accelerate is higher than the torque in engine braking cases. So would you explain?

What mechanical issue is at work that causes greater wear on clutch when doing engine braking?

Does the pressure plate increase the clamping force when the torque is applied from the engine side rather than the transmission side? I've only seen systems that increase clamping based on centrifugal force and that is RPM based so the clamping force would be the same at a certain RPM regardless of acceleration or deceleration. Since engine braking increases RPM when you down shift this would actually result in more clamping force.

Is the friction material some how made to have a different coefficient of friction in one direction that the other? Seems this would be a Chemical Engineering and manufacturing nightmare to insure a consistent material with a different coefficient of friction depending on the forces applied..

 

[NIsaacs]

In my understanding, using an exhaust brake in some circumstances will put the same "reverse" stress on a clutch disc as improperly downshifting.

They do put some reverse stress on the clutch but not enough to really matter as long as the clutch is fully engaged when the brake goes on. I have not seen any damage on any of my Cummins powered trucks, they are all exhaust brake equipped. My '91 has 318k on the original clutch. At 280,000 miles I changed out the throwout bearing and re-installed the oem clutch, it was fine. An exhaust brake only has about 190 retarding horsepower at max rpm, if a clutch will handle 300/400 hp it will handle that.

I grew up driving non syncro manual trannys, if you didn't learn to rpm match you didn't go anywhere. Syncro's are a trannys worst nightmare, as a general rule, they cover up all the sorry shifting of the general public. I wonder how many 6spd manual trannys were subjected to a 4th gear acceleration going for 5th only to end up in 3rd? All kinds of things break clutches and trannys, the exhaust brake is not one of them.

Nick

 

[photowrite]

I grew up driving non syncro manual trannys, if you didn't learn to rpm match you didn't go anywhere. Syncro's are a trannys worst nightmare, as a general rule, they cover up all the sorry shifting of the general public.
Nick

Amen to that!

My wife drives a manual transmission [her car] fairly well, but just a few days ago I decided to 'diplomatically' remind her of something I'd shared a few years ago... If she would shift just a little slower, letting the transmission fall into the next gear when it's ready, and use less force, particularly on the 1-2 shift, the gearbox would be happier. I told her it might not be an issue soon [the car is newish], but possibly for the second or third 100k if we keep it that long.

 

[NIsaacs]

Everyone's entitled to their opinion but I never turned off my EB in 398,000 miles except for icy roads. Never failed a clutch, just release bearings and never opened the NV 5600. I also towed 18,000lbs in sixth when conditions were right.

I do the same thing with my NV5600, they are tough. Here is a picture of one, I will try and explain why they are so strong. Note where 6th gear is, it is up front next to the input shaft, very little room for torque related torsion. If I am running freeway speeds I stay in 6th if I can maintain 65 mph. With 400hp/950tq that's most of the time. On big hills or 2 lane slow roads I stay in 5th. Note the 3 counter shaft bearings and the 2 rear main shaft bearings, most trannys only have 1 on each end total.

The reason the NV4500 5th gear runs hot and or fails is because it only uses the one bearing per shaft end, and of all things, 5th is out side the main case. 5th is on the opposite end of the input shaft so the torque travels the full length of the shafts and case. Then to top it off, 5th gear is outboard of the rear bearing, it has a cantilever affect, huge no no.

I love my NV5600

Nick

 

[photowrite]

That is a cool cut-away, I'd like to see one like it for the G56 if it exists?

 

[AH64ID]

93k on my NV5600 and clutch is on its way out. I tow a 5k RV only a few times a year otherwise its a commuter and I have certainly towed in 6th gear :-( I did not know that you shouldn't. I also downshift a lot and was recently told not to do that with new diesels and transmissions...??? So I have been using more brakes vice downshifting. I also have a Jacobs brake that is used almost all the time.

Sounds like my clutch is failing early, any of the things above that I am doing wrong?

Thanks for any advice.

Garth

I don't think you are doing anything wrong, as others have said. Towing in 6th is fine, but rpms won't hurt either.

I typically hold 6th if I am around 2000 or higher rpms but have no issues dropping a couple mph and running 2500-2600 in 5th if needed. I don't like towing in 6th too much below 2000 rpms on any sort of grade but that is mainly due to lower oil pressure, airflow, etc.

I run about 400/850 to the ground and will often use most of that torque in 6th on grades with the engine load above 80%. The load rarely gets above 90% in 6th or 80% in 5th at the 19-21K GCW I generally run in the summer, even on 7-8% grades.

I asked because you made a declarative statement about synchro wear with Mobil 50. I did the research, listed the Mobil fluid you referred to and then compared it to Mobil 50. I also told you of Mobil's claim of it being safe for all yellow metal synchros. I'm waiting for your explaination of supplying false info to the other members. I bring this all up because bad info is often worse than none at all and we should all exercise caution when giving advise without direct knowledge. Whether any particular fluid is factory recommended is irrelevant, when one makes a declarative statement that is factually incorrect.

I really cannot figure out what your issue is.

Neither of the fluids you listed are NV5600 compatible, simple, factual, and really hard to ignore... you know that ATF isn't compatible with all auto's too right??? And didn't you have shifting issues with it? Cold or warm fluid shifting issues means the syncro's and fluids aren't working like they should be.

Just because a trans fluid is listed as a yellow metal compatible manual transmission fluid does NOT make it compatible with all manual transmissions. You used some good transmission fluid that was designed for different transmissions/syncro's regardless of their colors.

The only factually incorrect information is your ASSumption that Mobil50 is compatible with the NV5600. It's fairly mute for you now as you run an Aisin; however, some more research and fewer assumptions would have shown you that Mobil 50 isn't the proper fluid for an NV5600, despite how well it may work in a G56.

The NV5600 is one of just a few manual transmissions that has a different fluid requirement than most. It's not a big deal, and not hard to figure out.

But that's my last input on the subject as it is obvious this isn't going anywhere.

 

[ELK311]

Thanks all!!! I think it's time for a replacement 1947-OK-HD clutch and some better shifting habits.