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Trouble Rebuilding NV5600

4K views 12 replies 5 participants last post by  CJGuy 
#1 ·
Hi folks,
I'm halfway through my rebuild and have hit a substantial road block. I have the mainshaft out and the input shaft bearing came off rather easily. However, the rear bearing in this transmission exploded, and I am having a hell of a time getting the inner race off.



This is where I am at, as you can see I've used a burr on a die grinder to cut a track pretty much right down to the bottom. There is a similar cut 180 degrees on the other side. This thing will not come off. It's been heated, hammered, chiseled, in the press, heated again, air hammered, pressed again, I've got 4 hours into this one race.

I am a mechanic by trade and have done a few transmissions of the Fuller variety, but I've never had a part so stubborn. I'm pretty sure the surface of the mainshaft is now screwed anyway, but have any of you got over this obstacle in your rebuilds?

At this point I'm wondering if the race was spinning on the shaft and has friction welded itself together. Any help is greatly appreciated
 
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#2 ·
What I would do, and do all the time with getting races off shafts, is just take the torch and cut it off. You can actually cut right through the race without putting a scratch in the shaft, if you know how to do it.
 
#3 ·
RJF, I've cut through the one side with the torch, but the remainder seems quite seized on there. It's stood up to incredible abuse this far
 
#4 ·
I had a cam gear that had tried to slide off the cam in 50+ years of abuse and a 20ton press would not press it back in place, even after soaking with penetrating oil or heating with a propane torch. I ended up heating it with a propane torch and melting candle wax onto it a couple times and all of the sudden I could see it suck the wax down between the cam and gear. After that it pressed on very easily with the press. I am not sure if this will work for you or not, but it is worth a try. If your race is welded onto the shaft, then I would replace the shaft due to it getting too hot, so at that point torch it off or grind it off whatever it takes to get everything else off the shaft that you need to reuse. Good luck, and let us know how it goes
 
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#5 ·
Wax, eh? That's an interesting method, I have two cores that I am combining and may try that method on the race I haven't yet touched.
I had a local machine shop agree to have a look at the shaft tomorrow to see if they can turn the race off in their lathe. I figure as the bearing is a fairly hefty press fit, some surface scoring shouldn't be a huge issue
 
#7 ·
I've got two cuts 180 degrees apart, right down to the shaft. It has been heated, pressed and air hammered, which has removed every other bearing I've worked with. Suppose one could just keep making cuts, however I'm more than a little worried It's friction welded on there
 
#8 ·
From your description it is welded to shaft. With it cut in two places, welded is the explanation. Shaft is ruined. Grind it down till get gears off.
A procedure for getting stubborn bearings off (won't work in your case) is put a weld bead on bearing. The heat will expand and race will fall off. Bearings are replaced anyway.
 
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#10 ·
Machine shop called, said they turned the bearing off in a lathe, and the shaft looks screwed. Will inspect myself for tomorrow. The wreckers I bought the trans from said they'd warranty their core, and would replace it if the core wasn't rebuild-able. At this point, I'm 0 for 2 on a box that's actually rebuild-able, starting to wonder if there's any middle ground for these transmissions between working fine and failing catastrophically
 
#11 ·
Headed back to the wrecker today to drop off the third bum transmission. Managed to talk them into letting go of their "good" 5600 for a couple dollars more than what I was payed for the cores. This trans was a take out from a truck that was in an accident, and the bellhousing has a crack in it. Otherwise they say the internals are just fine and the gearbox is ready to go into service. So I brought it home.

Only issue is it is marked as '00, indicating it's from a 2000 truck. My understanding of NV5600s is that the first two years, '99 and '00, had an undesirable 1 1/4" input shaft and non rebuild-able syncros. This trans has a rebuild tag on it that is recent and it has the 1 3/8s input shaft. Was the switch between transmissions mid model year as Dodge seems to like to do? Hmm :confused013:

Hopefully the ordeal is over now

 
#12 ·
Rear bearing is a weak part in these, poor oiling design. Remember, lube oil in a manual tranny is not only for wear protection, it supplies cooling to critical high load components.
Shops that specialize in the 5600 do a mod to the rear bearing oiling.
Order the mod kit from Standard Trans. & Gear
http://twitter.com/share
http://blog.genosgarage.com/wordpress1/wp-content/uploads/2012/05/TDR67_MyNV5600.pdf

Why don't you just buy a new shaft and replace instead for trying to find used unknown quality junke yard dogs?

Put the Geno Trans Coolers on and fill that sucker up with at least 8 quarts of Redline or Amsoil, don't go thick on the viscosity of the full synthetic lube, doesn't climb as well in the vertical design.
Finned Trans Coolers cool much better than the non finned POS they sell. And put a temperature gauge on the tranny.

http://www.genosgarage.com/product/transcool-3/transmission-coolers

Or you get to do it all over again in a year or so, your wallet.

And there are 3 input shaft diameters on these 1 1/8", 1 1/4" and 1 3/8"
 
#13 ·
Rear bearing is a weak part in these, poor oiling design. Remember, lube oil in a manual tranny is not only for wear protection, it supplies cooling to critical high load components.
Shops that specialize in the 5600 do a mod to the rear bearing oiling.
Order the mod kit from Standard Trans. & Gear
http://twitter.com/share
http://blog.genosgarage.com/wordpress1/wp-content/uploads/2012/05/TDR67_MyNV5600.pdf

Why don't you just buy a new shaft and replace instead for trying to find used unknown quality junke yard dogs?

Put the Geno Trans Coolers on and fill that sucker up with at least 8 quarts of Redline or Amsoil, don't go thick on the viscosity of the full synthetic lube, doesn't climb as well in the vertical design.
Finned Trans Coolers cool much better than the non finned POS they sell. And put a temperature gauge on the tranny.

Transmission Coolers - TRANSMISSION COOLER - TRANS-COOL ('94-'05, NV4500/NV5600)

Or you get to do it all over again in a year or so, your wallet.

And there are 3 input shaft diameters on these 1 1/8", 1 1/4" and 1 3/8"
This is excellent info, thank you sir. I have a stream of cores from this parts house and all I'm wasting at this point is my time, hard parts like a mainshaft are no where to be found up here in Canada and short of buying a running take out which can fetch north of 3500 bucks around here, rebuilding a core seemed like the best option
 
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