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Dodge Ram NV5600 six speed manual transmission problem update. 
6-speed Manual Transmission Status
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Difficult shifts:

Posted to the TDRoundtable by Michael Brolin on 11-22-2001:
There have been cases of the 6spds not wanting to go into gear at idle. In one case, the dealer called the DC Star Center and was told to replace the clutch, pressure plate and flywheel under warranty. There have been rare occurrences, especially when towing at or near max GCVW, of weak pressure plates. After the tech removed the clutch, they saw that the throwout bearing was not hitting all of the forks on the pressure plate. At this time Star said to replace the slave cylinder because a small internal part will break off unbeknownst to the driver. All of this was done under warranty and has happened to about 600 trucks. BTW, the clutch had no signs of wear.

Gear Grind:

Many people (myself included) have reported a gear grind when shifting into 3rd gear while the transmission is cold. After the transmission has been driven for 5-10 miles, it shifts fine. Some owners have reported that after 12,000 miles or so, the transmission "loosens" and the shifting problem goes away. DC has issued TSB 21-009-01 NV5600 Countershaft Service to address the shifting problem..

NV5600 swap into older models:

JP Callan has installed the NV5600 in his 1998 12 Valve Ram. NV5600 Specs, and Swap Information are under construction.

NV5600 Test Drive:

My test drive of the new transmission at the 1999 Columbus IN TDR rally:

      The transmission is huge compared to the NV4500! Dodge provided 5 Rams with the 24Valve engine / NV5600 combination for us to test drive, and they stayed busy throughout the rally.
      My test drive was in a 2500 QC pulling a trailer of unknown weight, and this engine/transmission combination impressed me! The transmission shifted easily, I had no trouble finding the gears, the transmission was quieter than my NV4500 5 speed and, unlike my 5 speed which always seems to scratch through the 3rd gear synchronizer, the 6 speed was buttery smooth. The new truck (pulling a trailer) would quickly buzz to the red line gear after gear.

My seat of pants observations:

Conclusion: I thought the 6 speed was ideally suited to the power band of the 24 valve ISB, the engine just needs to be run at higher rpm than the 12 valves can turn under load. FWIW: I would like to try a 6 speed with a 12 valve engine sometime just to see how the extra gear would help with the narrow powerband of the older engines.

I spent some time asking questions about the problems with the transmission that caused the NV5600 production delays for the last two years. The story I received was that Jayco had been testing the transmissions for Dodge, and experienced repeated failures with 3rd gear and reverse. Reverse on the 5600 is installed on the tailshaft in the same place that 5th gear was mounted on the NV4500, hmmmm....

Third gear problems may have been due to a lubrication problem, but no one would say. I also heard that the input shaft bearing has been made larger.

A year after the 2001 models reach the market, more than a few people have complained about the shift from second to third gear when the transmission is cold. This is a definite grind into third, (much worse than a synchro scratch) that sets your teeth on edge. It usually occurs during the first few 2nd to 3rd shifts when temperatures are below 35° F. Double clutching the first couple of 3rd shifts is about the only way to avoid this grind. Some have reported that 10,000 miles loosens the shifting and the grind goes away. With 18600 miles on Sue's truck, it occasionally grinds into 3rd in cold weather, but the problem appears to be going away as miles accumulate.




Page last updated: August 6, 2002