Did the googling and came away more confused than ever ... Heading out to a charity rally in a few weeks, getting some overdue manitenance done on the Formula.

Lube in the transl ast switched out in the early 2000's with Royal Purple Synchromax, still listed on their site in MT applications for Dexron II/III and others.

Wondering two things: Is there a better choice for a NWC '87 T-5 (all stock) say in the Mobil 1 family? And is it wise or advisable to add the small bottle of Slick 50 trans additive?

Apppreciate the patience and collected wisdom!

 

If it's the 1st design transmission, with brass blocker rings like older 3- and 4-speeds and straight roller bearings (in fact the rear countergear bearing is the exact same part # as a 10-bolt axle bearing), it needs gear lube. Mobil1 75W-90 works great.

If it's the 2nd design, with the composition blocker rings like automatic transmissions and tapered roller bearings with preload, it needs ATF or Synchromesh.

ATF is too thin for the older transmission, in spite of it having occasionally specified in a year here or there by the car mfrs. It NEVER was specified by the transmission mfr, NO MATTER WHAT you see in some years of the FSMs. The car mfrs decided to "cheat" the fuel mileage by a tenth or whatever, regardless of the inevitable shortening of the transmissions' life by inadequate lube.

Gear lube is not good for the material in the newer type.

I'm not a big fan of "additives". Can't see where there's very much for them to do, especially in the 1st design.

 

So, what is the tell between first and second-design NWC T-5s? My car was built after the TPI / 5-speed was released for production in Jan/Feb 1987 (Norwood, one of the last out the door there.)

Service manual and owners manual are defininte about the Dexron II/Synchromax.

My '84 SE with the HO V6 shifted like a cement mixer, just not as refined. That felt like a first design...

The '87 (LB9/MM5 (think it is MK6 on the broadcast) still shifts pretty much like the day I picked it up, notchy but that is not a bad thing, seems to be temperature dependent (?)

Thanks!

 

No idea what "notchy" is. If it is what I think it is, it means that you can feel the gears crash just a little bit when shifting. Probably especially from 3rd to 4th. If that's what yours does, it's not the transmission, and changing the fluid won't fix it (which is NOT to say "don't change the fluid", only that doing so won't fix THAT one thing). The cause of that is imperfect clutch disengagement, perhaps involving the pilot bushing, which even if the clutch itself is fine, a loose-fitting pilot bushing will allow the clutch gear (the thing that looks like a shaft, that the disc rides on) to flutter around in there, and the disc will touch the flywheel and pressure plate when it's supposed to be free-wheeling, which is what makes the gears crash.

Also note that I REFUSE to use that stuuuuuuuupid 80s "total quality" "PIT team" "six sigma" BUZZWORD that somebody's summer sophomore intern in the marketing department thought that it would be "trendy" and "modern" and "youthful" and all such as that to apply to the 2nd design of that product, and which later on in hindsight, the 1st design, by way of "features from the future" thinking, is now colloquially referred to as "non" ... that. It makes me vomit.

Anyway...

Here's photos of both. 1st on top, 2nd on the bottom.



Observe the front countergear bearing. It's the object about 2" diameter, down low on the pass side of the case front. 1st design is flat, very shiny, with its edge looking rolled-over since it was a disc of sheet metal kinda pressed into a receptacle in a die. 2nd design is dull grey, has a depressed center leaving about ¼" that looks raised around the edge, and has very sharp edges, since it was forged and machined that way. You can see it easily while the transmission is installed in the car; it's left partly exposed by the bell housing. You can see the witness mark from the BH on the 2nd design one.

Observe also, the brownish stain below it, on the 1st design one. That's from the inevitable leeeeeek where that bearing is supposed to be a press-fit into the case butt no longer is. The case is too weeeeeeeek to hold it, and "stretches" across the front from the force trying to pry the gears apart when loaded heavily, such that the hole becomes an oval instead of round. Then, since the press-fit is supposed to be the seal to hold the fluid in, it leeeeeeeks out around it. Meanwhile, since the hole "ovals" out in the direction of allowing the countergear to move away from the clutch gear, it allows the gears to misalign (too far apart). When the gears misalign, the force spreading them apart is multiplied, leading to the case becoming more "oval". The more the case ovals out, the higher the spreading force is; the higher the spreading force is, the more the case ovals; the more the case ovals, the faster the fluid leeeeeeks; the faster the fluid leeeeeeks, the more the gears tear up; the worse the gears wear, the higher the spreading force is; the higher the spreading force, the more it ovals; the more it ovals, the higher the spreading force; and so on. I think you can figure out where this is headed. Once it starts, which it ALWAYS does, it speeds itself up, and inevitably runs its course to the same end if the transmission continues to be used. It's a "positive feedback" loop (the kind of sequence that perpetuates itself, can't be stopped once it starts, and grows on its own) with seriously negative consequences, and is utterly inevitable and unpreventable except by not driving it: it's too weeeeek even for that lame 2.8 they put in these cars back then, you can tear one up even with THAT. You might call it "circling the drain". The case in the photo is one of MANY I destroyed, and the clutch gear in it is one of at least a dozen I bought and tore up, before I (a) quit trying to drive it like it was a 4-speed and reluctantly began to take my foot off the gas while shifting, and then (b) replaced it with a 2nd design which I treated like an egg in the drive train, and then when I got tired of babying THAT, (c) completely got rid of those POSs and replaced them with a T-56 which solved the whole issue.

Observe yet further, that on the 1st design, there's a kind of strange wear or witness mark maybe 3/8" wide all the way around the edge of the countergear bearing. Note how it fits neatly up under the edge of the clutch gear bearing retainer (very large round rusty thing). That's because the case in that transmission "stretched" to the point that the bearing was SO LOOSE, that it spun in the case, and rubbed the retainer. Obviously that is a COMPLETELY FORNICATED transmission, and obviously a bearing that fits so loosely in an oval hole that it can spin, doesn't have a prayer of holding the fluid in. I'm so glad I don't have to deal with those POSs anymore, and I hope yours isn't as bad, yet. The 2nd design bearing is NOT a press-fit, butt rather, drops in loosely, butt it ALSO has an O-ring for sealing rather than hallucinating that the bearing itself is gonna handle that, so the rotation in the case is expected and accounted for, and isn't harmful.

 

I would also point out, that a driver behavior that further aggravates this, is jamming the transmission into Reverse while the clutch is still spinning. You know, where the car is sitting there running, and the driver decides to back up, and they try to jam it into Reverse, and there's a good 2 seconds of loud gear-grinding noise before it goes into gear.

In the T-5, like practically ALL manual transmissions built before 1990 or so, Reverse is not synchronized. Gears are selected by locking one of the intermediate gears that normally floats on the mainshaft, to the shaft, by way of the shifting mechanism including the synchronizers. What synchros do, is to provide a mechanism that stops the shifting device (the sleeve) from meeting the teeth that mate it to the gear the driver is shifting into, by blocking the sleeve from moving all the way, until the speeds of the sleeve and the new gear are equalized (synchronized). They work by way of a ring (blocker ring) with teeth matching the sleeve, and a clutch surface (brass or composition, as referred to earlier), that as long as the gears aren't at the same speed, is rotated a little bit to one side. The teeth on everything, by way of being tweeeeeeked out of alignment and mashing against each other due to this slight rotation, press the ring's clutch surface against a mating surface on the next gear, until the speeds equalize. Then once the RPMs of the parts are equalized, the force rotating the blocker ring to where it blocks, is removed; and the sleeve can slide over its teeth and onto the teeth of the intermediate gear, gracefully and quietly. The sections of the drive train whose speeds must be matched up, are the part connected to the engine (clutch disc, clutch gear, countergear, and all the intermediate gears), and the part connected to the wheels (the transmission mainshaft, drive shaft, etc.). One of the parts whose RPMs must be equalized is the clutch disc, which is in fact the dominant carrier of angular momentum in the system, i.e. the hardest thing to speed up or slow down to the correct RPM, because it's massive and also the largest diameter piece.

Reverse is not equipped with this mechanism, therefore if you try to shift into reverse while the disc is spinning, the gears - the reverse intermediate gear, which is spinning at the speed the engine left it at when the driver pushed the clutch in, and the reverse gear on the mainshaft, with which it mates to put it in reverse, and which is largely sitting still just like the car is - EAT each other, until the engine side of things slows down and stops so that the gears can finally mate. LOUDLY. Most transmissions from before the 60s, for example the old Chevrolet 3-speed that they used until about 64 or so, didn't have synchros on 1st either; only 2nd & 3rd. 18-wheelers don't have synchronizers at all, so EVERY gear has to be double-clutched while shifting, to equalize the clutch RPM manually (pedally?) to approximately what it will be in the next gear. As the gears grind, they shed metal chips into the fluid, which then do what metal chips in any fluid always do; namely, EAT every moving part touched by the fluid. Bearings, gears, shafts, EVERYTHING. This is VERY EEEEEEEEEZZZZZY to prevent in a T-5: all the driver has to do, is to put the transmission into ANY forward (synchronized) gear BEFORE Reverse, to stop the clutch and transmission guts from spinning, and THEN put it into Reverse. So, ignorant driving technique is yet another detail that factors into shortened transmission life.

 

Beautiful car! Now, that’s a car you don’t see every day even on the interwebz.

 

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