OK, I want to be clear on this . . .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.
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?
> 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, Drivetrain.com 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 list of 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
> Philip... and anyone else interested in the input bearing saga. I've posted
> a program (Windoze only: IPBCV1.0.zip) that models the life of this bearing on the general message
[ . . . ]
> . . . 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.
> 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
> 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 http://www.drivetrain.com/nissian4_5sprwd.html
Input shaft bearing
Countershaft bearing (front)
56mm OD (thru '84)
62mm OD ('85-on)
Countershaft bearing (rear)
6204X (BCA 204)
Mainshaft bearing (rear) aka Overdrive Mainshaft bearing
6205 (BCA 205)
> 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!