I was wondering if everyone has ever put a sequential shifting trans into a Fiero and if they have any pictures or info on how they did it or what transmission was used. The idea of a sequential trans has always appealed to me, mainly because its different but also because of the benefits.

Are you talking about a tap-shift paddle trans, like the 4T65-E that has paddles?

Yeah, it's been done in a Fiero. Is it easy? Not that I recall from the build thread. Probably the reason why no one has really done it. There's a lot involved in making it work with whatever engine you have in your car, mostly because I believe most of these engines require both the transmission controller and the engine's ECM to communicate with one another. Darth Fiero would probably be able to explain more, since he does all the custom chips for the 3800SC cars that originally came equipped with paddle shift trans (I believe in these swaps the swappers use a normal 'shift' style trans).

Im talking about a true sequential trans, I think refer to it as a dog box? Basically a manual trans where the clutch is only needed in 1st gear and the rest of the shifts are up or down, no H pattern and selecting individual gears is not possible.

I have thought about it, even found some that would fit our stock engines. However, they are extremely expensive and not worth it. Sequential Shifting transmissions are not called Dog Boxes, any manual transmission with dog engagement is a dog box. All sequentials I know are dog boxes, but even an H pattern shifter transmission can be a dog box.

So far, only sequential I have seen in a Fiero was in a race car, severely modified, not street legal. They are good transmissions for racing, and racing only. Their engagement is extremely harsh, will do lots of wear and tear on all your bushings, mounts, etc. Unless your Fiero is a toy car, you bring out once in a blue moon for fun, and put her away in the garage most of the year, a Sequential trans will just be severely annoying.

The best workaround to it, is to use a paddle shifted electronic automatic transmission, or go for a DSG.

quote Originally posted by Jennings03: Im talking about a true sequential trans, I think refer to it as a dog box? Basically a manual trans where the clutch is only needed in 1st gear and the rest of the shifts are up or down, no H pattern and selecting individual gears is not possible.

Yeah I think you're a bit confused. With a dog box, you still have the standard H shift pattern. There are some in existence that have "slap" gears to go up and down, but a good variety still utilize an H pattern to shift.

What a dog box has is a gear set that allows little to no usage of the clutch. People often think this just means "straight cut" gears, but dog boxes can have both either helical or spur gearing. What a dog box won't have is syncros, like in a normal manual transmission, and it will allow for "flat shifting" (where the driver does not have to completely depress the clutch or left off completely on the gas to select gears). This is primarily through "dog engagement", which is a term to describe the very basic nature of how the gearing in a dog box works. It's akin to a setup that's like a simple set of cogs that have a wider space to slide into place, rather than the multiple engagers and syncros that are placed close together like on a normal syncro engagement transmission.

I don't see any advantages in having such gearing in a Fiero. As mentioned above, such a transmission in a Fiero is going to place it upon a tremendous amount of stress. Not just the transmission itself but the entire drivetrain is going to see excessive wear through vibrations. You also would have to be highly skilled at proper rev matching - not basic heel-&-toe, but at an advanced level to understand the movement of the gears in relation to the car's speed - to properly drive it on the streets. Finally, it would induce a tremendous cost upon the builder of the car. Not just in initial investment but also in upkeep and potential part replacement.

[This message has been edited by Fiero84Freak (edited 12-18-2011).]

I'll be honest I do not know much about them just a little reading here and there. And I figured the idea would be frowned upon. However I like having something thats original and different than everybody else. Its not something I plan on doing in the near future. And I wouldn't mind the style of shifting, my Mustang has a C4 with a full manual shift kit and I like the shifting. The main difference would be having the clutch for taking off. I think that the only way to get use from a trans like this would be to have the correct engine attached to it, I don't think a 2.8 or 3.4 is gonna cut it lol. Definitely sounds like it would limit the daily driving of the car but I think it would work great in an autocross car. As far as rev matching and stuff I'm not sure how much it relates but I find it fairly simple to do this with the Getrag 5 speed using no clutch. However like I said I don't know much about it I just think it would cool to do something different knowing I'm not gonna see another Fiero with the same set up.

quote Originally posted by Jennings03: As far as rev matching and stuff I'm not sure how much it relates but I find it fairly simple to do this with the Getrag 5 speed using no clutch.

You might want to reconsider doing that often if you like your syncros

Does it work on the synchros? Or just if you do it wrong? I've noticed that theres a fairly large range in rpm you can do this, however if you do it at the right rpm, about 2600 I believe, it glides in just as smooth as the clutch being pressed. But by all means if I'm potentially tearing something up I'd be happy to know sooner than later.

quote Originally posted by Jennings03: Does it work on the synchros? Or just if you do it wrong? I've noticed that theres a fairly large range in rpm you can do this, however if you do it at the right rpm, about 2600 I believe, it glides in just as smooth as the clutch being pressed. But by all means if I'm potentially tearing something up I'd be happy to know sooner than later.

Your synchros and blocking rings will be getting damaged yes. A very common sign to people who abuse their synchromesh transmissions in this way is when they change trans fluid, it comes out with golden colored particles, this indicates the blocking rings have been damaged and are very worn.

As for the sequential, the price of a sequential is in the range of $7,500-$50,000, FYI. If you want one, go ahead and throw it in, but expect to throw some serious coin and some serious engineering to make it work.

As for how it works, a motorcycle transmission is sequential. A shift kit in an automatic is NOT the same, not even close, the dog teeth in a synchromesh vs the teeth in the sequential are very different. RPM Matching is fairly easy in a sequential, however you have to properly load the dog teeth to allow the shift. So if you fully let off the throttle, it WILL damage the dog teeth, however if you are full on and try to shift, it wont shift or will grind. Also ALL sequential transmissions I know of have no reverse. You can throw a reverse add-in I believe, or have one made with reverse, but expect to pay some money. By default, they come no reverse, for they are for race cars only.

Best to get a dogbox conversion to a Getrag 5 speed or a F40 6 speed, with helical cut gears. Sequentials I believe are mostly spur cut, since again, made for racing not for daily driving.

This is hard to explain to someone who just knows they exist, and don't know the ramifications on adding them to mostly stock vehicles. Here is a list of things that need tending to, to add in a sequential.

Frame - Strengthening to take the shock loads
Bushings - Replaced to Poly or Solid
Engine - The engine would not be proper for the application
Subframe - Needs rebuilding to allow the sequential
Mounts - Trans mounts need replacement, Not reccomended to use rubber, due to shock loads. Rubber ones most likely will rip after a short while
Interior - Routing the new shifting cable
Axles - Obvious reasons

Just to do a proper sequential trans conversion, Expect to spend anywhere from $15,000-$75,000, depending on where you can get deals. You must factor in the cost of the engine swap, performance clutch, Rebuilding parts of the car, and the biggest cost, the transmission itself.

quote Originally posted by Jennings03: Definitely sounds like it would limit the daily driving of the car but I think it would work great in an autocross car.

A dog box actually would be horrendous for autocross, considering that in most autocross runs you hardly shift gears at all. Especially in converted parking lot circuits, you barely get enough speed up to warrant actually changing gears. Most of the time it's staying in between a 2nd to 3rd gear or maybe if you're lucky 4th gear range. You very rarely get enough speed to select higher gears. Having a dog box in this situation would just slow you down because you couldn't use it to it's full potential.

Hence, this is why a dog box is most effective in full-on race applications, such as straight line drag or circuit racing. If you're using every gear in the trans, then it's doing it's job. However, to be limited by the rather lower speeds that typical autocross can put on vehicles a dog box would be a wasted endeavor. Money is better spent elsewhere in building an autocross car.


It has to be quite a harsh ride if a dog box were in a Fiero. The design of the rear end of the car already allows for some movement naturally. Remember that very often some drivetrain power is lost through natural movement of the drivetrain itself as bushings soften the movement. To see such a big modification's full potential, you would have to solid mount just about everything back there and the suspension would have to be really stiff. I bet in a Fiero it would be a ridiculously harsh ride, especially in the shifts if you didn't know how to drive it right.

[This message has been edited by Fiero84Freak (edited 12-19-2011).]

If you want sequential shifting, and to avoid the clutch, you could swap in an auto with tap-shift, or a CVT. The CVT might be better depending on what you want to do with it, since you could program it for a near infinite amount of shift points between the two limits of the transmission.