I recently got to sit in a manual f-body (99 Trans AM) and got to go through the gears. Ive been in a few C5's and it seems that they're 6 speeds are lighter and more precises than this trans ams. I also noticed that in neutral(going right and left) it felt alot heavier than the vettes. So do you think that this T/A's 6 speed was a little messed up or is it supposed to feel less precise and heavier than a vettes? If so whats the difference other than the vettes have a transaxle?

 

Vettes have a triple synchro design where as the fbodies have a dual synchro design. The vettes are also an external rail shifter with a linkage (the reason they feel tighter) where a fbody has an internal linkage design.

 

Yup...the vettes have a different trans setup because the transmission is mounted to the Independent Rear Suspension and connected to the engine via a "torque tube".

 

The vette also has a remote( not direct mount) shifter. The detent loading is somewhat"tunable" in any T56. If you just sat in the car and went through the gears( not driving) you did not get a real measure of the shift quality as dynamic shifting is what you really experience when driving. If the shifter / stick were aftermarket, this would also affect the feel.

 

Both are internal rail shift system. The vette, as Calhoon stated has a remote/non-integrated shifter.

Corvette

http://www.rsgear.com/TREMEC/T56Corvette.pdf

Features and Benefits:
• Double overdrive Provides extended ratio coverage and allows for closer ratio steps
• Aluminum die cast housings Lightweight, durable construction
• Tapered roller bearings on shafts Reduced noise and improved durability
• Needle bearings under speed gears Improved high speed performance and reduced shift effort
• Advanced synchronizer technology -

Powered steel formed blocker rings Consistency, high quality

Organic friction material Improved durability

Triple cone design Lower shift effort

Patented strut-type design Improved durability
• Overdrive synchronizers placed on countershaft Lower shift effort and reduced noise
• Constant mesh, synchronized reverse Positive engagement, improved durability and reduced noise
• Internal, single rail shift system Enhanced shift feel, improved durability


F-Body

http://www.rsgear.com/TREMEC/T56.pdf

Features and Benefits:
Six-speeds Applicable to a wide range of vehicles requirements
Double overdrive Provides extended ratio coverage and allows for closer ratio steps
Aluminum die cast housings Lightweight, durable construction
Internal, single rail shift system Enhanced shift feel, improved durability
Tapered roller bearings on shafts Reduced noise and improved durability
Constant mesh, synchronized reverse Positive engagement, improved durability and reduced noise
Integral clutch housing w/adapter ring Increased driveline bending strength with mounting flexibility
Overdrive synchronizers placed on countershaft Lower shift effort and reduced noise
Advanced synchronizer technology -

Powered steel formed blocker rings Consistency, high quality

Organic friction material Improved durability

Double cone design Lower shift effort

Patented strut-type design Improved durability

 

sorry to resurrect this thread, but my interest is this precise topic:

The issue is "double" -v- "triple" cone synchronizers.

I've seen the parts for what I call a double cone synchro. I call it couble because there are 2 friction surfaces rather than the single surface of conventional designs. (All muscle car synchros are single surface: brass ring bearing on gear cone.)

The multiple cone synchros are an evolution of the synchro "clutch" into a multiple clutch setup like motorcycle clutches.

So for the double cone, the brass ring stays the same, but the inner cone is moved from the gear to the hub. A new part is added, the middle ring which is between the brass ring and the inner cone. This middle ring is dogged to the gear. The middle ring inner and outer surfaces are utilized resulting in the "double."

So for a triple cone, you should need 3 surfaces. Once you see how you "stack up" the synchro "clutches," you see that the inner cone would have to go back to the gear and 2 middle rings would have to be employed: one dogged to the gear, the other dogged to the hub. The outer brass ring stays the same in all these designs.

My only concern is that I've never seen a so-called triple cone synchro and suspect that they actually do not exist (3 friction surfaces.) The misnomer may be that the triple cone indicates there are 3 parts where there were once 2 which still leaves us at 2 friction surfaces.

At SEMA or PRI, one of the transmission gurus there said there was no difference between the double and triple cone and that it was just semantics.

Can anyone verify this???

NOTE: I've spent a lot of time surfing trying to find cross-sections of these designs and have come up empty. It was only until I saw a transmission at SEMA (or PRI) was I able to actually see the double cone in the flesh and to my delight it was configured exactly as I hypothesized. That was cool.

Thanks

 

You have taken information from a bogus "guru". The Tripple cone sychros that are in T56s do, in fact, have 3 friction-lines elements.If they say they make no difference then they may have been selling 2-cone(lower capacity)units . T56 synchros., both 2 & 3 cone designs,do not use brass( a very old-school/ low RPM material)but a carbon-particle lining. The tri-cone are used in 1st&2nd only.

 

well, I used "brass" as a generic word. yes they are using automatic transmission clutch material on them.

he maybe have been referring to 3-4 since the 2-3 shift is the killer.

I really, want to see a cross-section or description of the 3 surface sunchro.

Is the design just an extension of the cone method? For 3 surfaces, the inner cone would go back onto the gear. Is that true?

 

No ,they are not using auto clutch material on them( they used to).The carbon-particle lining was enginered specificly for manual transmission cone clutches.It replaced the composite paper linings ( auto tranny stuff) due to the great increase in durability.The Brass is hardly a generic for high end synchros as it is most definitly old school.
I think you have a mental block seeing the tri-cone stack . There are 3 friction elenets and 3 cones. One element has friction material on the inner and outersurfaces. There is a cone on the gear and there is an element that has a cone on the exterior and friction element( the 3rd) on the inner surface.In the T56 this stack fits in the same axial space as the double cone parts.
BTW when we say 3-cone it is for 1st and 2nd. In the tri cone design 3rd &4th and 5th & 6th are double cones.It the double cone design 1st and 2nd are double and the remainder are single cones.

 

Let me try to describe my vision of the 3 cone stack:

Starting from the innermost:

1) Gear w/cone,
2) Ring: ID: Friction Material, OD: smooth cone (dogged to synchro hub)
3) Ring: ID: Friction Material, OD: friction Material (dogged to gear)
4) Ring, Outer (i.e."brass ring"): ID: smooth cone (dogged to synchro hub)

Friction surfaces between 1-2, 2-3, 3-4
Friction surface consists of friction material bearing against metal cone.

 

Here's a set( yes its old , yes composite- paper-lined)

 

Thanks for the picture.

The big issues is getting the Corvette synchros into the F-body.

What I find interesting is that the triple cone is "more similar" to the single cone since a "conventional" cone is used on the gear. The obvious question is how hard would it be to mod the triple cone system into 3-4, 5-6???

(I have T10 and Toploader parts coming out my ears.... wish I had piles of T56's to play with.)[BTW the 2.78 low Toploader Rules the muscle car 4-spds.]

 

It would not be too hard at all to get these into an Fcar. The GTO has'em and they are thes ame basic dimensions. It will have a 2.97 1st instead of a 2.66.Gotta swap shifters.
To convert your trans requires a change of all the clutched gears(5), mainsaft, input shaft and all the sinchro parts.

 

I was at PRI and some of the vendors were making this mainshaft that has an added flange to use the Corvette parts in the base T56.

But, like you said, if the GTO has it, then that would be the one to sub w/o replacing internals. Does the new Viper have it? That T56, I think, is rated at 550 lbs ft or something like that - a BIG increase over all other models. I was wondering how they justified that leaving main-counter shaft spacing the same. Usually reducing low gear ratio is only way to significantly boost torque capacity.

Have you thought about the triple cone modded into the 3-4?

Someone needs to do a GTO conversion kit or instructions, eh?

 

The torque rating(higher) of the new Viper is accomplished with gear/ shaft design & materials. The ratios were unchanged .The synchros are the double-cone design.

 

I'll bet they changed the helical angle, a la RockCrusher (that was an M-22, right?)

 

Only the helix of 2nd gear was revised. The remaining change was material/ process based.

 

That's interesting, I know back in the 70's when they were promoting high strength gear sets based on some 9000 series alloy, a lot of the local drag racers said they completely disappointed by the claimed increases.

I'd still like to get my hands on one since I have a 96 GTS.