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There is no question that I am worried something costly and inconveniently-timed is going to fail inside my GR6.

I searched a number of posts for specific info relating to Nissan's "Metal Cap" TSB and also the benefits of the Willall Gear Stoppers but didn't find exactly what I was looking for.

Are these two items designed to cure the exact same problem or are they unrelated? I.e. do I choose one "solution" over the other or install both?

The Nissan TSB doesn't give any technical details describing how the Metal Caps work or what they actually do to eliminate the MIL from reoccurring. Willall's site does provide some decent info.

In an older post John Shepherd of SHEPTRANS fame said:
We have been seeing these for awhile on the newer transmissions
This is to prevent the corners rounding and letting the pistons rotate.
Please explain how this is limiting travel in any way.

John
John's comment "Please explain how this is limiting travel in any way" has me even more confused. Is John suggesting that the Nissan Metal Caps don't limit the travel to protect the synchros?

This is the post I found from Willall:

Nissan have also chosen to address the problem the same way Willall have by limiting selection throw to the correct amount to prevent this over-selection.I would suggest we have a more elegant solution in our WR35GS Gear Stopper system that uses plastic acetyl parts that install internally in the shift pistons to prevent this damage rather than an external metal clip as Nissan have done. External clip-on solutions are easier to fit from a dealer point of view with the quoted 1.7 hours of labour in the TSB, however for a more durable and potentially safer solution - nothing can dislodge or drop into the transmission the way we do it - fitting WR35GS should only take in the order of 3 hours.
Once I can figure out which "fix" is best for my needs I will have the work done ASAP! While the ACM is out I would like to install a new filter and I understand the only option is the cylindrical mesh screen from Dodson. Other than it being fairly expensive, can anyone think of a reason why I should stay away from this aftermarket filter?
 

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These are actually different problems.

The "overselection" is breaking teeth off in the mechanism, and by limiting movement of the piston, the overselection is reduced. WillAll stops it with a small shim. Dodson solves it with a harder ring, that the teeth don't break.

Nissan's caps are dealing with a slightly different, but related problem, the fact that the forks seem to have some play. With this play, the piston shafts are "thrust" in different directions, rounding the edges of the shaft (supposed to be square), and forcing the piston one way, scoring the surface. WillAll's discs may help (because the piston limited may not flex as bad on the fork, but I have no way to vouch for that), but that's not what they were designed for. Dodson solves this problem with a much beefier shaft, with a totally square shaft with no play. It appears to not respond at all to flex in the fork.

Honestly, one could install ALL THREE of these updates, and they would likely play well together (although I cannot say the clips would fit properly over the Dodson shafts).

Shawn
 

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John's comment "Please explain how this is limiting travel in any way" has me even more confused. Is John suggesting that the Nissan Metal Caps don't limit the travel to protect the synchros?
Yes, he is. As above, I cannot say if WillAll or Nissan's solutions "cross fix" the other problem, or make it worse. WillAll and Dodson disagree on how to solve the problem they were discussing. Dodson redesigned the shift ring with teeth so they wouldn't break off. WillAll puts a small shim on the end of the piston to keep it from moving so far.

Shawn
 

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Thats essentially the crux of the situation Shawn.
We are great believers in reducing the travel that Nissan gives by installing WR35GS - which if not fitted can drastically overselect in some instances and is IMO partially responsible for the broken selector forks that some folks are starting to see now in upgraded transmissions.
Controlling shift travel as we do is nothing new in transmission design, only new to a dual clutch application.
We have never seen a broken dog ring or damaged selector fork with WR35GS in place.
 

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The two parts are totally exclusive of each other i.e. you can fit the caps without the WR35GS gear stops or the stops without the caps. Neither interferes with the other. The good news is that fitment of WR35GS Gear Stops is very similar in terms of work to fitting the caps, its probably only another 30mins of work if you are fitting the caps and doesnt require the transmission to be disassembled etc. Thats why we consider the WR35GS upgrade a good investment in the life of your transmission
 

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The two parts are totally exclusive of each other i.e. you can fit the caps without the WR35GS gear stops or the stops without the caps. Neither interferes with the other. The good news is that fitment of WR35GS Gear Stops is very similar in terms of work to fitting the caps, its probably only another 30mins of work if you are fitting the caps and doesnt require the transmission to be disassembled etc. Thats why we consider the WR35GS upgrade a good investment in the life of your transmission
I need instructions on this install, Martin. I am STRONGLY considering installing your gear stops when I open my transmission for wintertime maintainance.

Shawn
 

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No problems Shawn
Its as simple as popping the circlip out at the end of the shift piston, pushing the piston out, putting a stopper up the far end, pushing the piston back in, putting a stopper on the circlip end and reinstalling the circlip. WR35GS limits the travel of the piston, no more, no less
 

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I finally got my hands on a set of Gear Stoppers. They are nicely machined but I was a bit surprised to discover they are made from a resin material (Delrin?) and not metal. Willall must believe in this material but I wonder how long they will last being bathed in a petroleum product at 200F+ and smashed with each shift? Maybe it will become more obvious once I get around to fitting them.
 

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I finally got my hands on a set of Gear Stoppers. They are nicely machined but I was a bit surprised to discover they are made from a resin material (Delrin?) and not metal. Willall must believe in this material but I wonder how long they will last being bathed in a petroleum product at 200F+ and smashed with each shift? Maybe it will become more obvious once I get around to fitting them.
Looks like they are made of some of the same stuff that is on the valve body itself. That kind of plastic resin does just fine in that environment.

Shawn
 

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Shawn you are correct the material chosen will go the distance in a GTR transmission

The last thing we wanted to do was introduce more metal/metal clashing inside the transmission, so a plastic based stopper solution eliminates the chance of further component fracturing. Our original design used metal stops, and we very quickly moved away from that after analysing a set over a test distance.
 

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Should be not too hard to install.

Drain your tm oil.

Remove the oilpan and hold a plastic tray under it to avoid spillage.

Push two pins through the thin holes of the valve body to hold the shift solenoids

Remove four hexbolts that are holding the valve body.

Disconnect all the connectors including the big ones when removed the valve body.

The valve body should come off.

Remove the clips holding the valve stoppers.

Place inside it and do it on both sides.

Close both sides.

The rest can be done reverse wise from here.

Fill up with FFL-4 if there is no OEM TM oil.

Prime the clutches 1M 5sec > 2M 5 sec(only LC2).
 

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This past weekend i installed in my 2010 the Willall Gear Stops,Dodson Shim Caps,pan filter magnet kit and reusable trans filter.This was my first time ever working with an ACM.I am a mechanic by trade but specialize in Rotary Engines.All i did was follow the instructions on the Nissan Service Bulletin on how to install the metal caps.The Bulletin calls for two retaining pins that prevent rotation of the shift pistons.Well,i did not have them and do not worry about it at first ,because once you remove the ACM the article will show you how to find the correct alignment of the pistons and at this time you can make your retaining pins.(The article shows a picture of them)To install the Gear stops is as simple as Martin explained it earlier.I looked at all the pictures and read all the articles and it was still not very clear to me but once i had the ACM in my hands it all made sense.
 

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This past weekend i installed in my 2010 the Willall Gear Stops,Dodson Shim Caps,pan filter magnet kit and reusable trans filter.This was my first time ever working with an ACM.I am a mechanic by trade but specialize in Rotary Engines.All i did was follow the instructions on the Nissan Service Bulletin on how to install the metal caps.The Bulletin calls for two retaining pins that prevent rotation of the shift pistons.Well,i did not have them and do not worry about it at first ,because once you remove the ACM the article will show you how to find the correct alignment of the pistons and at this time you can make your retaining pins.(The article shows a picture of them)To install the Gear stops is as simple as Martin explained it earlier.I looked at all the pictures and read all the articles and it was still not very clear to me but once i had the ACM in my hands it all made sense.
I would also like to say how helpfull that Nissan service bulletin was! I sure would like to see more info like that available on the GR6.

I've currently got a GR6 in my shop with broken selector ring. A replacement selector ring from Dodson cost $1000!!!
 

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I would also like to say how helpfull that Nissan service bulletin was! I sure would like to see more info like that available on the GR6.

I've currently got a GR6 in my shop with broken selector ring. A replacement selector ring from Dodson cost $1000!!!
IF the shafts were not able to float and IF you properly blueprinted the stops it would be ok to limit travel. The fact is that the stops are not accurate and the design of the trans allows the shafts to have end play. This is a production based gearbox and there is no possible way a one size fits all stop is the right way to do it. We have different methods to get around this for the time being that go into every build we do. We are having replacement sliders made in large qty so that will bring the price down considerably.
 

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Shep, the stops work well enough to avoid broken synchro dogs, this is proven via use over time. In fact our WR35GS stops work well enough to intermittently stop first gear selection with some of the incorrectly machined indo-chinese first gear/1-6 upgrades out there that would normally smash the selector fork due to an incorrect lead-in on the gear. Each to their own on this one.
 

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Shep, the stops work well enough to avoid broken synchro dogs, this is proven via use over time. In fact our WR35GS stops work well enough to intermittently stop first gear selection with some of the incorrectly machined indo-chinese first gear/1-6 upgrades out there that would normally smash the selector fork due to an incorrect lead-in on the gear. Each to their own on this one.
I have not run across this on the gears we use ( PPG ). The stops also do not let the slider engage fully ( not even close ) on units we have had in the shop which I certainly hope that you would agree is not ideal by any means. The lead in on the engagement tooth angle is not meant to be partially engaged. The real answer is sliders with beefed up stops, not changing the way it stops. Obviously I am talking about a box that is already in for an upgrade.
 
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