Dirk

Are there any specific physical differences between the T-5 and the T-5 World Class i.e. internal parts? Is it possible to build a regular T-5 to World Class standards? Also is there a difference in the flywheels? Will the internals from a WC T5 fit in a non-WC T5 case?

I know the internal parts question has been answered, but I am posting this for a friend

Thanks!

Jim85IROC

iTrader: (2)

www.5speeds.com should show the internal differences.

The case is the same. My 2.8 uses the same case as my 91 World Class unit. Oddly enough, it looks pretty much the same inside too. I've "borrowed" parts from the 2.8 trans.

RB83L69

The case is not the same inside at all.

It is not possible to do that, unfortunately. The 1st design uses straight roller bearings on the countergear (in fact the rear one is the same part # as a 10-bolt axle bearing) while the 2nd design uses tapered rollers with preload on the CG. The bearing bores are different diameters and the 2nd design rear has a place to bolt the retainer which the 1st design lacks.

The internals will not interchange, although I believe that you might be able to swap the later mainshaft and all the gears on it into the earlier case, and get the compostion synchros that way. But that is of very limited benefit by itself.

The flywheel is irrelevant. It's not part of the trans. You just have to use the right flywheel for the motor you have (1-piece RMS or 2-piece, balanced or unbalanced, 153-tooth or 168-tooth)

Dante93GTZ

iTrader: (5)

Long dead topic, but I am curious; what is the difference... with 8 more years of info being collected by users, someone has to have some pics by now.

sofakingdom

iTrader: (1)

Pics aren't really necessary, but I'll supply one anyway, just .... because I can.

https://www.thirdgen.org/forums/atta...c-t-5s-1st-2nd

The answer above is correct. It's all you need to know.

"World Class" is a "1-minute manager", "total quality", "ISO-9000", etc. etc. etc. TRENDY BUZZWORD from the 80s that for some reason, some inexperienced middle-management idiot in the marketing dept at B-W probably straight out of Ops Mgmt class at night school must have decided was a good idea to use as the name for the updated design of the T-5. Of course, like all "trendy" things, it is now LAUGHABLE, as no self-respecting person in any kind of corporate responsibility role would actually utter that meaningless drivel any more, for fear of people thinking they fell asleep in 1985 and just woke up yesterday like Rip Van Winkle. It belongs FORGOTTEN, along with disco "music" and Harvest Gold appliances and fender flares and sidepipes. It means ABSOLUTELY NOTHING WHATSOEVER, except as a "trade" name for "2nd design". It is not a matter of "standards"; it was a minor design revision that somehow got that stupid buzzword attached to it, is all.

As stated above, the original design had the countergear mounted on straight roller bearings. The inner race IS the gear, so when the bearing gets destroyed, the gear is ruined too, just like axles. In fact as stated above the rear CG bearing is the same part # as the axle bearings in the 10-bolt rear in these cars. You can spot the difference in the front countergear bearings instantly from outside the case, with the trans installed in the car even. It is a large round thing in the front surface of the case, down low, up against the bell housing, about 2½" in diameter, about ¼" of which is visible below the BH while installed. The 1st design one looks like an inside-out freeze plug, with a sort of rolled-over looking edge and a completely flat shiny surface, while the 2nd design one has a depression in the center that leaves about a 1/8" wide rim sort of feature all the way around, and has sharp edges and a dull finish, and has the brand name "Timken" visible around the edge.

The 2nd design case has different size bores from the 1st design for both CG bearings, and uses a bolt-in retainer on the rear of the case to hold the rear one. The 1st design does not have any of that. Therefore the cases do not interchange and the gears do not interchange from one case to the other. The 1st design CG is free to float a few .001"s from front to rear and has a tanged thrust washer at the front and a tiny Torrington at the rear for thrust; but the 2nd design uses tapered rollers with about .008" or so of preload and no discrete thrust bearings. The extension housing, where the 1st design Torrington goes, is therefore also different.

So, bottom line, they are completely interchangeable externally, but very little can be swapped internally from one to the other. All exterior dimensions are identical. Either will bolt in where the other was, subject to application-specific differences. A Mustang one or a S-10 one won't bolt into a Camaro or Firebird, for example, but a 91 Camaro one will bolt right into a 84 Firebird, if they're both V8s or both 6-cyls. Different mfrs changed over from ordering the 1st design to the 2nd design in different years, and maybe even for different car models; Frod started ordering the 2nd design for Mustangs a year or 2 before GM changed over the ones for these cars which was in 87 IIRC. Not sure when the S-10 changed. There are many application-specific details; these cars require the shifter pad to be rotated the same amount as the trans is rotated in the car and of course have the unique torque arm mount, the S-10 ones have the shifter about 6" farther forward, Mustang ones have all different splines and bolt patterns everywhere from GM ones, there are various clutch splines and shaft sizes on different ones, different gear ratios available, etc., all of which prevent one from one application from being useable in any other.

People make some kind of a big deal over the torque "ratings" of the 2 models. IMO there is no difference in actual strength, regardless of the fantasy-land "ratings": both are too weak to have any business behind ANY V8 motor, even one as gutless as the LG4 or L03. People even shred them all the time with 6-cyl motors. There simply isn't enough metal in them, period. Both revisions have the same tiny shafts, the same itty bitty gears, the same weak flimsy case thickness, and so forth, which ultimately is what determines the "strength" in terms of breaking, not the bearings which is almost all that's different. About the only significant effect the design change made was a slight improvement in gas mileage, since the 2nd design has all the intermediate gears spinning on roller bearings on the mainshaft when they're not engaged, instead of on bushings in the 1st design like older 4-speeds and such. Also some of the synchro clutch frictions in the 2nd design are composition, like auto trans clutches, where the 1st design uses all traditional brass ones. Much ado is made about the fluid as well, which IMO is a bunch of useless noise and chatter about nothing; GM themselves flip-flopped back and forth between gear lube and ATF a time or 2 with the 1st design probably due to either the gas-mileage or the warranty-cost concerns being more financially important in that particular year, and settled on ATF for the 2nd design although gear lube will work fine in spite of hot-rodder myth lore that says the clutches need ATF. This is not true, the primary reason for changing from gear lube to ATF was - you guessed it - gas mileage, as a tweeeek to help lessen the huge hit to the impossibly stringent CAFE requirements in those days that these cars made.

I could take pics of internal parts, as I have about a half-dozen of them laying around, but they wouldn't really mean much. Note in the pic, that on the 1st design one (the top one), the case has failed; the stain of leaking fluid below the CG bearing shows that it is stretched making the hole oval, which misaligns the gears, which renders it impossible to successfully rebuild a transmission inside this case. Note also that you can see a mark on that bearing where it has been spinning in its bore and rubbing against the back of the clutch gear bearing retainer, which has left a witness mark pattern about 3/8" wide all the way around it. That trans is wasted in the most common failure mode.