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Life with the new 6 Speed Manual


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Hi Cummins Mopar Fans,

 

Just wanted to give an update on my auto to 6 speed swap. I couldn't be happier. First off, I had everyone on here giving me things to try over the last eight (8) years to help me get my automatic problems solved, gear hunt fix, something like 6 altenators, ground cleaning, let alone hundreds of hours researching trying to find a cure. I want to thank Whie98Lightning for suggesting a swap after he sent me a diagram for the TC lockup switch. Mine even wanted to hunt w the switch on. Like he told me & I agree, that (the switch) was the only thing I could do to keep driving the truck.

 

Also, all the deap pedal issues are gone, the truck seems like it picked up 50HP, my turbo now lights at 1500 instead of 1700 RPM. I can shift when "I" want to hold the truck at the best gear for any situation. Yesterday I sold my Dad's 57 Chevy 1/2 ton & delivered it on a car hauer w no issues, that's a first, I would usually have at least a gear hunt or dead pedal issue of some sort. Now I can tow in OD w/o worrying about killing the 47RE. Yippie! Seems like my fuel mileage is up a little as well.

 

6 in a row & 6 on the flow,

Dave

 

 

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I've heard that when towing you should never use 6th.   Use 5th gear since it's straight through 1:1 ratio. 6th uses an intermediary gear & I've read somewhere that it can't take the extra stress of towing, something about the bearings being weak & heating up.

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I've heard that when towing you should never use 6th.   Use 5th gear since it's straight through 1:1 ratio. 6th uses an intermediary gear & I've read somewhere that it can't take the extra stress of towing, something about the bearings being weak & heating up.

You can use 6th gear but I wouldn't suggest climbing grade with it. Make sure you don't lug in a high gear it does put a lot of stress on bearings and such.

6 Speed in 6th Gear is 0.73:1 ratio

5 speed in 5th gear is 0.75:1 ratio

6 Speed in 5th Gear is 1:1 ratio

5 speed in 4th gear is 1:1 ratio

Not much difference...

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The used 6 speed came w all the parts to convert, cost me $2,000. Went w a 13" South Bend single disc clutch. Was going to go w a 2 piece driveshaft, had it made, but was so out of balance that it was cheaper to go w a one piece 4" driveshaft. So the transmission was gone through, new 6th gear bearing & 6 1/2 quarts of syncro fluid.

 

Thanks for the 5th & 6 Speed comparison Michael. I was sort of hoping that 5 & 6 would be more OD like they do on the new Chrysler Automatics, but I'm more than happy w what I have! I will be careful w towing uphill in 6th. After driving w an auto truck all these years, I know the comfort zone for the truck. I drive my vehicles for longevity so I will heed you words of wisdom!

 

I totally recommend the auto to manual swap!

Dave

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It is way more important to have a tranny temp gauge on any manual tranny that tows, when I worked at the gear shop it was truly amazing how many 5 and 6 speed trannies we got in behind the cummins that were literally melted down from input shafts and bearings on the 5 speeds to bearings and shafts and 6th gear totally melted on 6 speeds.

 

We talked most into putting tranny temp gauges in the rigs that towed heavy a lot and several customers came back thanking us and were in total amazement at how hot they got and also at how fast and cool they stayed by dropping one gear while towing.

 

 

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It is way more important to have a tranny temp gauge on any manual tranny that tows, when I worked at the gear shop it was truly amazing how many 5 and 6 speed trannies we got in behind the cummins that were literally melted down from input shafts and bearings on the 5 speeds to bearings and shafts and 6th gear totally melted on 6 speeds.

 

We talked most into putting tranny temp gauges in the rigs that towed heavy a lot and several customers came back thanking us and were in total amazement at how hot they got and also at how fast and cool they stayed by dropping one gear while towing.

I agree here,  but  for  additional  reasons!

Heat  (there is  plenty in these  transmissions for sure!)    isn't  what's killing  the  trans....  It's the  oxidized  oil.     So   keeping   the  lube  changed out    waaay  earlier than    recommended   is   paramount.    Pretty sure   most  owners   only  start  considering   oil  AFTER  the  transmission's been rebuilt!

Added   capacity....  Oil coolers   add  what,  a quart each side?     the  increased  fill  level,      Wrapping the exhaust   along the trans  can't hurt either.

WF's   idea of  adding   a  gauge   will    help you   find  out if  YOUR  driving style is  detrimental.   it'll sure  clue you in if  you need to   add  additional  cooling devices. 

I  plan on  installing one..  just to  keep a  mental  file  on hand.   If  I see   long runs  at  higher  temps...  I'll  change the fluid  more often.    It's  annually for now.  (about  15-18 k  miles)

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It is way more important to have a tranny temp gauge on any manual tranny that tows, when I worked at the gear shop it was truly amazing how many 5 and 6 speed trannies we got in behind the cummins that were literally melted down from input shafts and bearings on the 5 speeds to bearings and shafts and 6th gear totally melted on 6 speeds.

 

We talked most into putting tranny temp gauges in the rigs that towed heavy a lot and several customers came back thanking us and were in total amazement at how hot they got and also at how fast and cool they stayed by dropping one gear while towing.

  What should the normal operating temp be for the NV5600 towing and not towing?

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Standard of any component, want to stay under 230+- a few, anything over 240+ is what breaks down the oil and things go down hill fast at that point. It also depends a lot on if it is synthetic or standard oils used and what weight of oil as well. Synthetics can handle closer to 300 for short periods and dino oils will degrade at a lower temp and sooner.

You get into oil flash points where it becomes extremely flammable at between 350-500 depending on oils and viscosities, this is well beyond any oils capabilities of protection, it was long gone dead before getting to this point.

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I know what you mean...... Mine just got out of a transmission shop yesterday!

I hope you have better luck w that than I did. Had mine rebuilt w an RV TC, all new sensors, thought I was set, WRONG, 4th gear hunt came w a vengeance this time! Bye bye 47RE.

Guys I still have the trans temp gauge for my auto, where should the temp sensor go on the manual?

Thanks for the words of wisdom guys, I won't be towing that heavy, but heat is the enemy here!

Dave

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Drill a hole in the side pto cover and mount it right there about mid point of the oil level. depending on the sender you may need to weld or braze a fitting into the cover to screw the sender into. They do make pan fittings that have a seal washer on both sides and the sender screws into the fitting.

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Joecool, I was able to use my original ECM. Now the only issue w my truck is the nut behind the steering wheel!

 

Since my fluid is updated in my trans, what should I run in the rear diff?

 

Thanks,

Dave

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what should I run in the rear diff?

 

Lots of people will most likely jump for synthetic lubes.

 

Me personally I tend to hop for the petroleum GL-5 80w-90 (light duty) 85w-140 (heavy duty). When people clear 1 million miles without axle failures that run truck for hotshotting I would say it a good selection.

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Lots of people will most likely jump for synthetic lubes.

 

Me personally I tend to hop for the petroleum GL-5 80w-90 (light duty) 85w-140 (heavy duty). When people clear 1 million miles without axle failures that run truck for hotshotting I would say it a good selection.

 +1 ^^^^^

Just  as   you'll need to keep  the  trans  fluid    changed  ( for  heat damage)       axles  need     love too!        Contamination  from  water  and   low  levels  due to  leaks    are  probably  the   #1   consideration.

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I asked the guys at my local diesel performance place, they said to use two (2) quarts of 80-90W.(May call the dealer just to be sure.) They also said that I don't need a temp gauge on a manual trans. Mine's a mechanical gauge that I have tucked out of the way, have the sensor, just need a bung! I'm going to hook the gauge back up, think you guys know what's up on this one!

Dave

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