Page 1 of 9

SD2x transmission issues: FS5W71x series of 5-spds

Posted: Sun Dec 18, 2005 2:46 pm
by asavage
[I originally wrote this in July to August, 2004 in another venue; now I am reposting it here. I'm splicing several posts together here.]
crazydatsundriver wrote:> I guess the conclusion of this is that the Nissan 5-Speed transmissions are all very close, from 1977 to 1986 and that they all have some form of interchange, whether they be L20B, Z22, Z20, Z24, SD22 or SD25.
OK, I want to be clear on this . . .

I've acquired an '82 KC w/SD22. The previous owner replaced the input shaft brg, but too late: teeth snapped after about five miles after replacement. This is the condition in which I purchased it: 5-spd is now out of the truck, gear teeth in bottom of case, lots of metal on the magnetic drain plug and the speedo drive gear (nylon) is chewed up.

I'm not contemplating rebuilding this one; too much is shot.

However, I'm very interested in the possibility of acquiring a gasser 5-spd and swapping its internals to what I believe you are calling the bellhousing (but what I consider to be the transmission's case, as it includes a good 2/3rds of the length of the entire unit).

If I understand correctly, this can be done?

kamloopsblake implies that that's what he's done:

> I had no problem switchin in a 5 speed from an 82'
> 2wd gas. All that was required was to change the bell
> housing. The gas transmision does have very minor
> differences in ratios.

Assume that I'd replace the easy bearings in the process, of course.

So, just to be clear: is this possible?

crazydatsundriver replied
> Yes it is possible, and requires a lot less work than you would expect. Be
> sure that the transmission length matches. Some gas trannys are
> shorter than others.

I appreciate the confirmation. I'm going to go look at a possible donor vehicle today (gasser).

Some URLs of note:

FS5W71 rebuild kits, including gaskets, seals, shaft locknuts (latter confirmed via email), and extension housing bushing, part No. MRK100600 for 1974-85, $138. They also offer the synchronizer rings as a kit, part No. ASK600 for $49.

Exploded view of the FS5W71 transmission (the view is of the "C" and later version, but should be largely the same as the "B" and "A" versions).

Interchange listof various Nissan models. Well, more like a list of Datsuns that use the same basic FS5W71 design. Scroll down to the "rear drive" section, and you find that variously the 200sx, 240sx, 280zx, 300zx, and rear-drive Maxima share the same basic transmission in various years.

Omega Machine & Tool offers the extension housing bushing alone, part No. 71411

longgonesilver replies:
> Philip... and anyone else interested in the input bearing saga. I've posted
> a program (Windoze only: that models the life of this bearing on the general message
> board.
[ . . . ]
> . . . Regarding the loading of the input bearing of the 5 spd gearbox. I
> rashly offered to calculate how close it was to its load limit. A simple
> calculation showed it to be marginal, so I embarked on a project to model
> its lifetime given varaitions in the engine/driveline combination.
> I won't go into details of quite what it shows, except to say it confirms
> the need to be kind to this gearbox. The larger engines are quite
> capable of chewing the input bearing in as little as 30,000 miles.
> Even if you are not interested in the bearing life, it is quite a fun program
> in that it lets you change engines, tyres, drop in a different back axle, all
> without having to pull-over.
> Notes:
> a) I have tested only W2K, though XP will certainly be OK and W98 is
> likely to be OK.... apologies to the Mac folk, but there is only one of me :-)
>b) unzip the attached file and drop it on your desktop. It requires no
> installation.
> c) this program doesn't touch any settings on your PC. Delete it and it has
> gone... for absolute sure.
> d) I haven't covered every possibility..... post up any requests here and
> I'll see what I can do
> e) don't get upset if it doesn't tell you what you want to hear :-) I did it
> for fun, and when the fun stops so do I.

Just freakin' amazin', Dave. Good Job!

At 60 MPH on a level surface, an estimated 10% of input bearings on the early FS5W71 will fail at about 131k miles.

I suppose that explains why mine, which hauled around a camper much of its life, failed before 89k miles.

Well, I put the gearset guts from a '79 gasser's 5-spd into the '82 diesel case last night, and it all bolted up fine. Some things I noted:

* The method of gearset removal outlined in the FSM is the easiest way: remove the extension housing first (remember to turn the selector toward 1st gear!), then hold the mainshaft at the tail, and use a deadblow hammer on the bellhousing to separate the gearset adapter plate from the housing. I found that I could not do it the other way round: no amount of beating on the gearset adapter plate or input shaft or front of the CS would separate the two more than about 1/2", but less than 30 seconds of tapping the bellhousing, and both transmissions came right apart. Weird but true.

* The tailshaft housing on the '79 is slightly different. There is an additional mechanism that bolts into the side of the housing that interacts with the selector fork on the '82.

* The bolt flange on the housing, where the housing mates to the steel adapter plate, is taller on the '79. I discovered this because I am re-using my '82's housing, and tried to use the '79's bolts -- too long by about 1/2". They can probably still be interchanged, using appropriate bolts.

* I bought a new extension housing bushing for the driveshaft (about $16 at Transmission Exchange in Portland, Ore.) and had a machine shop down the street install it -- they're handy. I don't have the correct pilot to do that kind of work. I thought about using heat and an arbor press, but decided to just pay them to do it ($30). They constructed a plastic mandrel and did a nice job pressing it in. It has to be located in the housing in a specific way.

* The donor '79 trans drove perfectly, no noise, no grinding, before disassembly. When I got it apart, I'd already decided that I was going to replace the four "easy" bearings anyway. When I removed them and cleaned them off, I could see significant wear on the inner races of all four. If I was to do it again, I might perform further disassembly and replace the two larger bearings contained in the adaptor plate as well.

* I used a two- and three-jaw puller for the two "front" bearings. A jaw extension was necessary for the input shaft bearing, it's about 10" from the end. Both the rear mainshaft bearing (behind the speedo drive gear) and the rear CS bearing were easy to remove, once the requisite snap rings and swedged nut were removed, using a small punch and some light tapping (for the mainshaft brg) and a deadblow hammer (for the CS brg). No presswork needed in either direction, but I cleaned and lubed the shafts before disassembly, which helps.

* Input shaft seal = Federal Mogul/National No. 1981
Extension housing seal = 3771

* The speedo drive gear (the one on the mainshaft) is steel on the '79, nylon on the '82.

And, contrary to what I expected, both the gasser '79 and the diesel '82 had steel front bearing retaining plates, not the alum. casting I expected on the '79. Maybe somebody put a diesel one on it before I got it? Or, maybe Datsun didn't switch to the alum plate until after '79? Who knows?

In case anybody's interested, here's the prices for the bearings:

BCA 205 $26.64
BCA 306-LO $71.02
BCA 204 13.40
NTN 63/22 $90
Extension housing bushing $16

Fortunately, I pay a little less than that, but it's still not exactly cheap. Add in the two seals, front gasket, and a clutch, resurface flywheel, it adds up.

My '79 gasser's reverse idler has 23T and a couple of 1/8" chips.

I called Transmission Exchange in Portland, Ore. to order some other parts, and inquired about a reverse idler. They couldn't furnish a new one but offered a "good, used" one that didn't sound any better than mine. One thing to note: the tech said that there were (at least) three different tooth counts on that idler: 21T, 22T, 23T were mentioned specifically.

The local Nissan dealer said he should be able to get the 23T reverse idler for about $81. I declined to order one, and re-used mine instead.

I have an acquaintance who (ab)uses a 720 4WD gasser; he has three FS5W71s with reverse out of all of them.

My failure in the '82 FS5W71 was definitely the input shaft brg, 6306N (30mm ID, 72mm OD ?)

I'm pretty sure it was the CS brg (63/22X C3, 22mm ID x 56mm OD) that changed dia. Let me look it up . . . yup, the 4spd got 52mm OD, the early 5spd got 56mm (63/22x), and the later 5spd ('85-on) got 62mm OD for the front CS brg. Naturally, the case is different. I don't know if one could machine it out to use the later brg in an early case.

Reference for much of this is

[much later]
Input shaft bearing
6306N (BCA306-LO)
30mm ID
72mm OD

Countershaft bearing (front)
63/22X C3
22mm ID
56mm OD (thru '84)
62mm OD ('85-on)

Countershaft bearing (rear)
6204X (BCA 204)
20mm ID
47mm OD

Mainshaft bearing (rear) aka Overdrive Mainshaft bearing
6205 (BCA 205)
25mm ID
52mm OD



longgonesilver replied:
> The countershaft front bearing is clearly still the weak point, and
> apparantly one Nissan was aware of as they stepped the bearing size
> twice. Why twice I wonder? Surely they can do a bearing lifetime
> calculation? I would guess there was an economic factor such as getting
> return on investment in existing tooling.

I'll tell you, that mainshaft was a bugger to remove. First, the nut is not something that would yield to persuasion using a light touch -- unlike the CS nut, which came right off on both transmissions. But the real trouble was removing the damned "overdrive gear bushing", a sleeve that must be removed to remove the OD synchronizer hub, to allow the mainshaft to slide through its centre bearing.

I thought I could just unbolt the retaining plate (six T40 torx flathead screws, pull the plate back and read the brg Nos., but noooooo. I could read the CS brg but the mainshaft brg was installed with the numbers facing the shoulder.

Heat wouldn't budge that OD bushing, I had it nice and cherry red all 'round, and it was still locked hard. Ended up using a cutting wheel on a 4" angle grinder.

Good thing I didn't have to try to salvage any of these parts, as in the process of just looking at these two bearings, I ruined the mainshaft, OD bush, and OD hub -- though I wasn't really trying to keep them in good shape; they're now in the scrap pile out back.

Now I'm glad I didn't try for these two bearings on the other trans (the donor one I used to assemble a "good" box for my '82 diesel). I'd have had to send it out for the presswork, I don't have any jaw pullers with a long enough reach for that OD hub, and my split bearing puller would have fit behind it, but the assy wouldn't have fit in my press. My vocabulary isn't large enough!

[end of tale summary]
The '79-gasser-guts-into-'82-case project worked well. I replace the four "outer brgs, input & output seals, and extension housing bushing. In 12k miles, it's shifted perfectly. I don't notice the small difference in gear ratios. I've changed the gear oil twice since then, and the first time the magnet was slightly fuzzy, nothing on it the second time. Gear oil is cheap, compared to the alternative.

Keep the transmission oil clean and change it regularly for best FS5W71 life!

Posted: Thu Apr 20, 2006 7:41 pm
by asavage
I used 75W140 conventional gear oil by Chevron in that truck. If it had been my own truck at the second oil change, I would have switched to synthetic AMSOil 75W140, but the truck was a year out of my hands by that time, and she puts 3-6k a year on it.

Interval is hard to say, so much depends upon usage. When I was doing this for a living, I went by color. I used a subjective grading scale of 1-10 with 10 being new oil as a baseline and 5 being the point at which I recommended replacement. Three or lower was basically black/opaque. I would write (with paint pen) the number on the gearcase, for future reference. Because I used the same color of latex gloves, the same lighting, and the same reference oil, this worked well enough for me; I was doing a lot of it for a while.

However, recent model domestic differentials turn their oil opaque/black within 5k miles, hard to believe but I've had my (gloved) finger in the fill plug of hundreds of them, and it's true. Many of them are now factory fill with synthetic oil, but I still don't trust oil whose color is significantly darker than new. I'm an oil snob, and I like clean oil. I also wouldn't try to sell a diff service on a truck that new, it's like paddling upstream, but the black crap in some of those diffs is really nasty. Horsepower has gone way up in the truck market (I recently read something like 93% increase in HP in the light truck market since 1983) but diff technology hasn't changed, and who changes diff oil? It's not on most people's mind. Trans oil's the same way. Selling diff or trans service is tough on a new rig, I didn't bother after the first few tries. And you should see Toyota AT oil after 30k! Not red, not orange, BLACK. Still, they don't seem to fail any sooner than anybody else's.

Import diff oil is quite good looking after even 100k. Nissan, Toyota, Subaru manual trans & diff oil hold up extremely well (color-wise) compared to any of the domestics.

That said, with what I know about the FS5W71B, two years max would be my starting point. Oil is cheap, even synthetic oil is cheap compared to the alternative.

Posted: Thu Apr 20, 2006 8:29 pm
by philip
asavage wrote: SNIP

That said, with what I know about the FS5W71B, two years max would be my starting point. Oil is cheap, even synthetic oil is cheap compared to the alternative.
Thank you, Al. I have since thumbed through the FSM and found only a recommendation to check the transmission oil level ... no changes. How odd. Yet, for trucks pulling trailers, there is a 30k mile change called out for the differential.

At the moment, I -had- 29k miles on RedLine 75w-140.ns oil. I bought Royal Purple 75w-140 this time because it specifically mentions GL-4 (and GL-5) suitability. It's a synchro thing with me. :wink: I'm a 'short shifter' 1st-2nd gears.

The RedLine oil came out fairly clean on my fingers but definitly brown in a jar. With the last couple of days being in the mid 80's again, the Idle/Neutral gear chatter is pretty loud.

Posted: Thu Apr 20, 2006 8:30 pm
by kassim503
I am a big fan of synthetics, especially amsoil synths (hence, the amsoil sticker on the back of my car).

Make sure you dont use the mystery brand oils that you have never heard of. I ran the cheap oil in my differential after my unsucessful attempt at removing my cv joints because I was planning on flushing it a few times before putting a fluid in for good. Within 4k miles the gear oil was black and as thick as molasses, and that was just 4k! I ran a amsoil synth for 10k before changing it and it was completley uneffected by the mileage. Good oil can really make the difference on alot of things.

Posted: Sat Apr 29, 2006 10:31 pm
by asavage
I used to do a lot of diff. service work. With a diff with a removable rear cover, I would burn at least two cans of aerosol cleaner and blow off all the black coating on the diff's interiour housing, as well as on the ring gear etc. Before I began that routine, that crap would foul the new GL5 pretty fast. I was tracking the same vehicles for years and could see how the change in procedure affected the color of the oil during routine scheduled checks.

On diffs without a removeable cover, or ones that for whatever reason we don't pull the cover from (ie Toyota front diffs, late GM rear diffs, and most diffs with a drain plug: import trucks mostly), I was just putting up with changing the oil more often. Like AT flushes, the intervals gradually got longer with regular checks/oil changes -- after the first change got delayed.

I tend to use AMSOil lubricants, in spite of the tenor of the organisation as a whole that I feel is somewhat of a turn-off. The oil is proven good, and I can buy it reasonably easy. I'd prefer an over-the-counter retail operation, but I settle for having the stuff shipped UPS; AMSOil does make it easy to get their stuff. I keep the 5W30 Heavy Duty Diesel oil in my own stock for the diesels I own, and the 5W30 std motor oil for the Aerostar and assorted small engines I have around, plus their synthetic multipurpose grease for the greasegun and bearing packing duty.

I don't think the difference between the top five "real" synthetic motor oils is enough to worry about. "Real" synthetic motor oils is API Group IV base stock, and in that category resides AMSOil, Royal Purple, Redline, and Mobil 1 (must have the '1' in the title). Everyone else's motor oil (in the US, that I know about) is API Group III or III+ base stock, and though their product is often marketted as "synthetic", it's not in my book.

Around here, Mobil 1 is as expensive as AMSOil.

Posted: Sun Apr 30, 2006 3:21 pm
by ecomike
If you have never rebuilt one of these little JOYS from the ground up, you don't what you are missing!!!!!

It is a shear $!%#! JOY to work on! LOL. Especially when you get to take it all apart again because you left something out!

I spent well over $700.00 on parts and tools by the time I was finished with mine, not to mention about 16 saturday afternoons in the Houston heat and humidity working on it. OK, so every other weekend was spent waiting on parts from out of town.

As I recall I reused the fourth gear, and the case and the housing parts by the time it was all done!!!!! I was so afraid of having to do it again, any time soon, that I replaced every worn, suspect part I could find.

Still I would not have trusted a local shop to do it right! I just hope and pray I don't ever have to rebuild it again.

Posted: Tue May 09, 2006 9:36 pm
by asavage
EvergreenSD wrote:I'm not sure what to think about the bearing issue. I want to be thorough but I don't want to have mission creep to the point that it's too much to tackle. Is the input bearing accessible from inside the clutch housing without splitting the cases?

See the two odd plates sitting on the bench to the left of the trans' case? One of those is the front bearings retainer plate (the other is a spare). It covers the front countershaft brg & the input shaft bearing.


That's where that plate goes. Yes, you can unbolt it when you are doing the clutch. Removing and replacing the bearing isn't a lot of fun that way though.

The previous owner said that he replaced the brg that way, and I bought it a couple hundred miles later with the input shaft looking like this:


A major problem is that there is nothing to grab on to on the bearing when you get that plate off. There's a external snap ring on the bearing, and that's it. It's pressed on to the input shaft: how do you pull it off the input shaft if you can't get behind the outer race? That's why I would split the case. And since you have the front of the case off, change the front countershaft bearing too, it's no more work, and nearly as weak as the input shaft's front bearing.

You will want to pre-order the gasket for that plate (it's cheap, a couple of bux) and the bearing (it's not cheap). I paid $71 for it, and I didn't pay retail. If you're willing to go with a Chinese or Mexican brg, you can probably get one for half that much. I'm not.

There is a quite good annotated exploded view above. And a list of bearing numbers and the prices I paid for them two years ago. Most of the pictures can be clicked on for larger/clearer versions.
I'm guessing the input seal should be replaced too if I do this.
If you disturb it, yes.

Posted: Sat Sep 02, 2006 10:32 am
by goglio704
Looks like I'll be learning more about the 5 speed before many more miles pass on my blue (230K) car. Drained the trans fluid today and was unpleasantly surprised to see that it had a heavy metalic appearance. The magnetic plug was completely coated and had about 5 large pieces of metal. The large pieces appear to have been about 20 gauge sheet metal. One has a real nice zig zag crimp pattern which looks to me like it passed between two gears! The others are just sort of mangled. Not sure what the metal used to be. Either a shim or ball retainer in a bearing would be my guess. Strange part is the trans is not really noisy and it shifts very well. I am inclined to think I need to look for a later model trans with the bigger bearings, and then swap the newer innards into my case. For now I am going to change the lube, change it again soon after, and monitor the situation. My gut tells me that there is enough wrong inside this trans that it won't be practical to repair.

Posted: Sat Sep 02, 2006 10:52 am
by philip
goglio704 wrote:Looks like I'll be learning more about the 5 speed before many more miles pass on my blue (230K) car. Drained the trans fluid today and was unpleasantly surprised to see that it had a heavy metalic appearance. The magnetic plug was completely coated and had about 5 large pieces of metal. The large pieces appear to have been about 20 gauge sheet metal. One has a real nice zig zag crimp pattern which looks to me like it passed between two gears! The others are just sort of mangled. Not sure what the metal used to be. Either a shim or ball retainer in a bearing would be my guess.
Within the first couple months of ownership, the trans in my '82 720 started making what sounded like input shaft rattle and fairly suddenly. The old "hot trans, Neutral, clutch released, idle" rattle. I did not wait for the Big Failure. I got the truck to a transmission shop before this bearing came apart, thereafter ruining the input and cluster shaft gears. I suggest you not "monitor" the situation any further.

Interesting thing here are several missing rivits and the fractured ball retainer. Additionally, this bearing (63x22 CS) was not supposed to have shown up until 1985 model production. (Al ?)


Posted: Sat Sep 02, 2006 1:15 pm
by goglio704
I normally wouldn't just monitor something like this either, but, as previously stated, I really don't expect to repair this unit based on what came out of it. This car doesn't see much use, but if I pull it now and tear it apart, I will only be creating clutter. I want to get another trans - preferably one that is a direct replacement. I would settle for an internals donor like what Al did, but I'm hoping the Maxima trans is not that rare. Time will tell.

Posted: Sat Sep 02, 2006 3:39 pm
by goglio704
Put fresh fluid back in the trans and went for a test drive - with ears on alert because I know something is wrong. I still don't hear anything. Looked closer at the metal chunks. They still look like thin sheet metal that has been mangled. Had to have been at least 1/4" wide before mangling. Does this sound consistent with the ball retainer out of one of the bearings? Is the retainer one of the first things to go? Could I have a very early stage of failure that isn't noisy yet? The metal that came out didn't look like the early stages to me. The plug was absolutely coated, and the fluid was shiny with metal for the first 1/2 of the drain. I know, I won't know till I open it up, but does anybody think it might be salvageable?

Posted: Sat Sep 02, 2006 4:44 pm
by asavage
Philip: the "63/22X" is the series, 22mm ID yes, but either 56mm OD (thru '84) or 62mm OD later. This is what I'm reading off the "white page" exploded view I annotated upthread two years ago.

Matt: sure sounds like ball separater metal to me. Got a camera?

The mass of metal on the drain plug is typical, the first time you pull it. Almost nobody changes transmission lube, MT or AT, so there may have been a very long interval to accumulate metal. Put only very good oil back in -- you know I like synthetics, but there are good mineral oil lubes too.

I think (but do not know) that the 280Z(X) trans is a bolt-in behind the LD28, unlike the SD engine. Used 5-spd 280Z(X) transmissions run around $250 here.

Posted: Sat Sep 02, 2006 6:31 pm
by philip
asavage wrote:Philip: the "63/22X" is the series, 22mm ID yes, but either 56mm OD (thru '84) or 62mm OD later. This is what I'm reading off the "white page" exploded view I annotated upthread two years ago.
Ah. I tossed all those bearings quite some time back. Oh well.

Posted: Sun Sep 03, 2006 8:29 am
by goglio704

What makes you think I'm anal enough to keep the pieces? Oh wait, I am. I'll try to get some pics up later. Trying to think the scenario out. The races and balls wear and the fit gets sloppy. This loads the balls unevenly and causes the separator to break as a precursor to catastrophic bearing failure. Does this sound about right? By the way, you may be right about the fluid possibly not being changed. The plugs were a bear to get out.

Posted: Sun Sep 03, 2006 9:06 am
by asavage
On this trans, the plugs are in pretty tight, and I know the lower one will leak if you don't put significant torque on it.