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Nv 3550 On 4 Angry Squirrels.

80K views 337 replies 21 participants last post by  Mr.ThunderMakeR 
#1 · (Edited)
Ok. I am starting my new thread that will re-appear from time to time to chart my progress, and or set backs, or complete withdrawal from this project all together. However, I will put my best foot forward with pictures and give it my best shot. If I do withdraw, I will state why, and give notice. But I do not plan on doing that, and my progress will be over a period of time. There are kits out there for sale to do this, so I am following their guidelines, only I am buying my own parts that they list to do it, to save money of course. And I have a major part of the list of things needed already. So, I am starting my thread to start monitoring my own progress and take notes for myself. This application works for ax15 transmissions as well, however, I happened to stumble across a new nv3550 for an excellent price, so I jumped on it, and that is what I am using. I hope this is of interest to all of us blessed 2.5 owners as most of you 4.0 owners are probably just going to shake their collective heads side to side and ask, "why doesn't he just swap to a 4.0?" The answer is, all the things I have make it more cost effective to just stick with my 2.5. I already have the necessary 96-98 dakota bell housing, for 2.5 to mate with the ax15 as they did with the dakota pick ups back then, and it will also work with the nv 3550 as I am using. I have the new NV 3550 transmission, I have the 23 spline np231j dated 1997 that is necessary to work with the trans. as the one on it I have now is a 21 spline. I just bought the clutch disc that is needed to work with my original clutch. p/n cp4198 (autozone) 9 1/8 o.d. but splines to match my nv 3550. I am going to order from Advance Adaptors a pilot bushing p/n (716167) nv4500, and a slave kit p/n (716340) that is said to work with my jeep hopefully tomorrow. The pressure plate and flywheel are also new as well as the Timkin throwout bearing. I do plan on putting a slip yoke eliminator kit, jb conversions, and obviously a new rear drive shaft. Not sure what kind yet. I need it as the new transmission casting is 2 inches longer than the ax5. Well, let me get started with something I really don't like what I see already..This is the disc required to work with the original clutch. the o.d. looks right, the splines look right, but, I noticed the side view angle, the spline column for the ax5 disc appears to be taller. I haven't measured it, but that's what it looks like. My first thought is just to add a properly sized washer to make up for the difference but I am not sure about that yet, or even if this really matters. But I need to know. This clutch disc is an application originally for a 4 cyl. camaro, 1984.
 

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#129 ·
Quick overview of the throwout bearings, different angles. Basically very similar in dimensions. The clips are somewhat different in design. Dakota bearing is on the right.
 

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#134 ·
Various views of the difference in the clutch discs. The ax5 is a used disc, but still works for a good basic comparison. The o.d. on the dakota disc is approx. 1/8 inch larger. Dakota disc is on right side.
 

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#135 ·
One picture of the pilots. Not really much difference as far as the depth. The dakota pilot may just be a hair deeper but not enough to factor in here. There are the obvious differences in i.d. measurements.
 

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#137 · (Edited)
This far exceeded my expectation. I did hone out the pilot just enough for proper fitment.
I attached my bell housing to my transmission, and then bolted up the flywheel to my new old stock 2.5. After all this time calculating the pilot, there really is no test like the real world application test.
So here is what I did, I applied a healthy amount of bearing grease around the input shaft tip area, and mated the transmission to the engine. I repeated this test 4 times to make absolutely certain what I was seeing was correct, and it is. The shaft drops into the bushing a little over 1/2 of an inch. This is really something I did not expect at all. This is a very good surprise. I expected far less. So this is great news. I was not able to get an accurate measurement of my bell housing depth on my AX5 I am currently driving but will not be using for this conversion, so this may account for the fact that it is more than I expected.
I hope this helps someone who is considering doing this swap, as I know personally I could not find enough detailed information that I am trying to provide.
 

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#138 ·
Thank you for persisting in documenting all the vital details, and doing all the heavy-lifting in pioneering this swap for the forum. Great pictures!!
 
#139 ·
Thanks Opihi. I have been meaning to pick your brain about the bleeder fix you mentioned earlier in the thread. Slave cyl. fluid is some pretty nasty stuff, not looking forward to that stuff splashing around. If you have something that will work I would appreciate it. There really should be a bleeder for the slave cylinder. It really is not good to not have one. I don't fully understand why they wouldn't have designed one in with the cyl.


The shifter and shift knob I will be buying early this week from advance adapters. My application part numbers are:
Shift knob p/n 716050k $19.32
Shift handle p/n 716099 $25.00
 

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#140 ·
Well, back on post 98, I was musing about rigging up some mechanism of bleeding the ext slave unit by removing the plug in the base of the threaded tower, and then rigging up some sorta bleeder screw. I have to come up with a ext slave to play with though, and may have found one in a JY yesterday which I will try to go back and get tomorrow. I believe with a little time and access to a variety of fittings, I could rig up a bleeder. If so, I'll let you in on the process. Might even have to make my own thread up on it if it works out.
 
#141 ·
I came up with an original ext clutch slave cyl from a 94/5 YJ 4cyl. In getting the thing cleaned up I noticed that it had a threaded plug in the top, with a 4mm allen head socket in it. At any rate, this is how the original units were bled. I am not sure when they decided to stop making that plug in the top removable, but I know now how to rig up a bleeder to the current new version that just have a plug in the bottom of the tower with no designed way to remove the plug. I took a lot of photos, but I am not going to jam up your thread with a series of photos unless you allow me to, or if you prefer, I will post it up as another thread.
The only issue I haven't completely done is to drill a hole in the plug in the currently available clutch slaves, and back that out with an easy out, and then actually convert the new model to bleedable. I don't have a busted new version to experiment with. At any rate, let me know how you would prefer I proceed with this.
 
#142 ·
Feel free to post everything in this thread. Probably anyone wanting to do this conversion may have the internal slave, and need to convert to external. So, the kit from Advance Adapters will probably be the choice of many. If you are willing to post the process here, most definitely yes, post it here.
 
#143 · (Edited)
Well, back on post 88 you showed photos of the ext slave kit with the hose, etc. A few posts later I put some photos up of the external slave I am using which came as part of the one piece, pre bled master/hose/slave unit. On this there is no provision for bleeding the slave and of course it isn't needed to be bled, but if at any point bleeding would become necessary in the future, you're hosed. I suggested that the plug in the bottom of the bleeder tower (I'm calling it that for lack of a better term) could be drilled, then extracted with an easy-out, then you could rig a bleeding mechanism up. I came up with an original clutch slave and it had come with a bleeder in it so I'll post up the photos of that. This is the bleeder plug in the tower, you can see the roll pin pushed out that holds the hydraulic line in the end of the slave.



The plug itself is threaded 8mm X 1.25 pitch and has a 4mm hex socket.



At the base of the tower on one side, there is a 1/16" hole drilled to the inside of the tower, this is a bleeder hole. When you back out the threaded bleeder plug in the bleeding process, the brake fluid/air would come out thru this little hole.



I looked at the slave unit on my Jeep, it has that little bleeder hole, and I am sure yours does as well, it just doesn't have the fixture cut into the plug that allows you to back it out for bleeding. I am supposing the plug that looks like this: (my NEW slave shown below, "non-bleedable")



.....is threaded in on a twist off shaft of some sort, and it shears off when it is assembled at the factory. Why they are made this way is beyond me. I went to a local Checker's last night to see what is available in the clutch slave there, and was surprised to find that the version they have has the hex head bleeder plug exactly like I pictured a few photos up in this post. The price on the unit was like $73 with a part number 4826285. I do not have a spare slave with the "non-removable" plug in it to actually test my theory that you can drill the plug and then put in an easy out and remove the plug, then fashion a bleeder plug threaded 8mm X 1.25 etc, but I suspect that this can be done. Maybe the best tool to try to use to do that is one of those combination left-hand turn bits/easy out that drills in til it grabs, then the piece backs out. The assembly into which it is threaded is plastic, and won't tolerate a wandering bit, or if the standard bit grabs, it can tighten in the plug and shear plastic threads, and if you drill thru the plug too far you could damage something further down in the bore. If you're really careful, you could even drill two holes partway into the plug and make a "pin spanner" to back it out. It does pose a challenge though, and if I had a spare, I'd give it a go at getting out that plug. Who knows why they weren't all made with a bleedable plug though?

At some point you're going to have to face this dilemma because the technique of filling your slave, and the hose, and getting out the air in the line to get good pedal will likely be a challenge, and the parts manufacturer took a giant evolutionary step backwards by making the plug non-removable. I apologize for illuminating the problems without posing a cogent solution, but I have the theory, and you have photos now of what is otherwise available, but $73 and change for a bleedable version is a bit steep when you already have a new slave.

For me, I wouldn't get the Advanced Adaptors kit, I'd get the one-piece, pre-bled clutch master/slave/hose unit and bolt it in. Can you send the AA kit back for refund and perhaps try this route instead?
 
#146 · (Edited)
This is exactly what I need to consider. It is very good information. I had no idea they sold a pre-bled system. That sounds far better. I do think that is a much better option for sure. Thanks again.
The one-piece, pre-bled unit is a simple solution, and when I did my external slave conversion, that is the route I took. It has the hose/master/slave already filled and all together and you just bolt it right in and go. I ordered mine from Morris Jeep in Pompano Bch FL it cost about $160 shipped if I recall correctly. Here it is installed, you can read the part number for the system. I found that local parts stores do not carry this, so it has to be ordered as I did.



I ordered the 1994/5 version as I was updating my 93 to this style. The clutch master, etc is different for the 97 and up as it includes wiring for a clutch safety switch, and has a much longer throw.
 
#147 · (Edited)
czjeeper, you mentioned you did the conversion earlier in the thread. You also used the dakota bell housing as well right? I know you have the ax15, and your slv. cyl. is the same design as mine? And you are getting enough engagement as well from the pin to release arm as well, how is everything working out? Good I imagine. I am thinking the pin" on the slv. cyl. has a good range on it to make up for the distance travel for the release arm. It is a bit further due to retaining the stock pressure plate.
 
#155 ·
That is correct.
I just bought a slave from NAPA and it came w/out the line. I drove the retaining pin out from the one I had, bled the slave, and installed on my line.
From what I've read, the reason people had to modify the push rod was because of the length of the "pivot stud" on the bellhousing.
I don't have ANY issues with shifting or engagement/disengagement.
 
#148 ·
Post 149. Thanks Opihi. You know it looks exactly the same as the one I have, and is definitely a much more convenient route I would have taken, and may still. On my steel braided lines there is a tag that states, "for off road use only". I used to use steel braided lines all the time on my street bikes. Is this just something they have to write to cover themselves for some reason? I don't see how street use is limited as steel braided lines are plenty strong. I was looking at the slv. cyl. last night again and noticed the plastic seat that sits between the bell housing and the metal slv. cyl. mounting bolt area. It comes off. I was considering the idea of possibly removing it. I know it serves some purpose, but that will give me that much more travel for the pin contact on the release arm. What do you think? Your picture there shows it very clearly.
 
#149 · (Edited)
I can't imagine why the line would be labeled "For offroad use only." I would feel that it would be superior to the plastic line, and I imagine this is just a liability disclaimer since it represents a modification of OEM parts.

Regarding removing the plastic "shim" or whatever it is called--the only reason I would pull that off is if you find you need more throw to the clutch slave. I would install it as is, and if a modification is needed, then that would be the time to start making alterations. Remember though those white plastic shipping straps.....they are not meant to be removed as the piston could launch and then your slave cylinder is toast, you'd also be right back to trying to figure out how to make a bleedable system, though the bleeding procedure for a non-bleedable slave has been described in your AA instructions, and has worked for at least one contributor to your thread in post 148.

There was a writeup on here recently which described the modification of a pneumatic cylinder for use as an external slave cylinder. I'll look for it. On that thread, it involved smashing the old external slave to salvage the metal portion or it, and using several large washers.....when I find it I'll post it up because it seemed to imply that the plastic shim thing was not removable as a separate entity. I'll look at my "spare" tonight and let you know more.

Edit--here's the link to the thread, there may be something of use to you in the links, and the rest of the thread. http://www.jeepforum.com/forum/showthread.php?t=701577
 
#150 · (Edited)
Thanks. I am going to re-read all of this tonight at work. I did call A.A. today, talked to a rep. named Gino. He said no problem on the return within 90 days. All I have to do is get a Return number from them, and send it out, and they will process it if I decide to do that. I asked him if they could just put the amount towards credit for another purchase, he said yes no problem, so I might do that. I am looking at the 2 wheel drive low kit, and installing that, or just go right for the s.y.e. kit for the transfer case. Not sure yet.
I did order the shift handle today, that's on the way. They didn't have the knob in stock, it sounded like he said they just have to order more from the dealer.
 
#153 ·
.....and yes, that plastic "pad" under the metal part on the external slave just clips off, but you already knew that.....

I suppose if you found you needed further throw of the external slave, you could remove the plastic pad and it would gain you almost 3/32 throw. I imagine it will take a lot of careful measuring and calculating so that your TO bearing isn't always up against the pressure plate fingers and either spinning, or also decreasing clutch plate clamping pressure. It isn't really a simple process to be able to see up inside the bellhousing unless you happen to have a surplus video endoscope laying around or something similar.
 
#154 ·
:rofl::rofl::rofl::rofl: No, no surplus video endoscope hanging around the house.
I think it is going to be the opposite problem of the bearing up against the pressure plate spinning, I would think. I will try it as it is when the time comes, with the shim on the front of the slv. cyl. Majority have had no problem with it.
 
#156 ·
Ahh, see now that is good information! On post #110, I found mine to rise just about 1 3/8 inches above the cast. I don't suppose you could shed a little more light on this as far as which height was problematic? That would be great if you could.
 
#157 · (Edited)
One thing I did not mention yet was the fact that I am buying bolts right now. I bought 4 so far. This the size that is working to bolt the dakota bell housing to the nv3550 transmission. I have no idea if the ax5 bell housing bolts will work. I have not tried it. I found them at Lowe's Hardware. I think they are $1.75 a bolt. M10-1.25 x 30.
 

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