This is a pair of Colotti dog box transmissions for AlfaRomeo 4 cylinder cars. They will fit anyAlfa 1965 to 1974. May fit earlier cars as well. They are not fortransaxle cars.

First, what is a Colotti dog box transmission…It’s builtinside a stock Alfa transmission case so it bolts right up to your clutch, but the similarity stops there. The gears can be interchanged, so you can setup a custom transmission for each track.And in fact, you can set up two transmissions because what I have hereis two complete transmissions plus a selection of extra gear pairs.

A Colotti dog box transmission,as the name implies, does not have synchronizers—it has dogs to engage thegears instead. This is a significanttime saver on the track. For upshiftsyou just let off the gas and jam the shifter into the next gear. It wants to be shifted quickly, don’tdawdle. For downshifts you can use theclutch and double clutch like you would on a normal transmission, or in theheat of battle just unload the gear with steady throttle, blip the throttle asyou go through neutral, and push the lever firmly into the lower gear. Starting off from a dead start can be trickybecause there is no synchro and the dogs that have to engage rarely lineup. So typically you can put thetransmission in neutral and let out the clutch to get things spinning, then depressthe clutch and engage first gear.

Theshift pattern is different from a normal transmission. Reverse is where first normally would be,first is where second would normally be, second is where third would normallybe, etc. So you have an H pattern for 2,3, 4, and 5. Also, instead of fourthgear being direct drive, fifth gear is direct drive. So you may need to get a longer rear axlelike a 4:10 for fast tracks like Willow Springs.

The gears themselves are straightcut and some have rather coarse teeth.This means that the load at any instant is only shared across one or twoteeth instead of multiple teeth like on a normal transmission with diagonallycut teeth. So the perfect use of thistransmission is for a smaller higher revving engine like a 1600. And you can make the ratios as close as youwant to suit a peaky engine.

Currently I have two transmissionsset up and ready to go. One, with allnew gears, is an ultra close ratio set up (2.17, 1.54, 1.25, 1.11, 1.0) and theother, currently with a good set of used gears, has wider ratios (2.54, 1.61,1.30, 1.13, 1.0).

In addition to these I include agood selection of additional gear pairs (11 in total, of which 5 are unused): A new 2.17, a new 1.73, a good 1.61, twopairs of unused 1.42, a new 1.16, and a good 1.13. The 1.73, 1.16, and 1.13 have some surfacecorrosion in the bearing surface of the mainshaft gears and should bepolished. There are also marginal gearpairs at 1.54, 1.35, and 1.2, and a good pair of input gears. Each gear pair from Colotti cost $500 or moreseveral years ago so this inventory of used gears is itself worth quite a bit.

And there’s more. Some of the bearings (like the large inputbearing) are standard Alfa items, and rather pricy. But some of the gears run on needle bearingswhich I could only find from Colotti, at a cost of $300 each. I have quite a selection of extra bearings,at least one additional transmission’s worth, and more like 2. See the picture.

Finally, I went through bothtransmissions in some detail. One of thecases was cracked so I replaced it and made sure both have everything in toporder. And then I never used either oneof them, they just sat on my shelf for years and years. So what you will get is essentially one brandnew Colotti close ratio transmission, another with slightly used gears, andenough spare gears and bearings (but not dogs, sliders, case) for at least yet another.

A word on parts: Colotti is still in business. They’ve been doing business since 1958,specializing in race transmissions. Here’stheir website: [link removed by ] As far as I know you can still order gears,bearings, etc from them. I did severalyears ago and the service was good.These transmissions are T118 in their parts system: [link removed by ] Colotti has made two types of gears for thisbox over the years. The onlydifference is the internal splines. Thetransmissions I am selling have the course splines, not the fine splines.

Oh, and I will include anoriginal factory CAD drawing of the transmission.

I’ll ship the two transmissionscomplete but with the covers loosely attached so you can inspect and change outthe gears as you wish.

If you want some additionalspares I have a box or two of miscellaneous standard Alfa transmission parts aswell I can include. But keep in mind ifI need to ship this stuff it will add to shipping cost.

The cost new for all this if youbought it from Colotti would be well over $10K, maybe closer to $20K.My reserve is less but not ridiculously low.

Obviously this is easier to shipif you can pick it up in Southern California.I can leave the whole shebang at Omega Motorsports in Culver City. Otherwise I can ship it at cost.

On Jun-03-17 at 09:20:24 PDT, seller added the following information:

I\'ve been buttoning up these transmissions this week getting ready to ship them to the successful buyer. I cannot seem to quite get the tailhouses on. There\'s about a 1 mm gap. You may need to put in a gasket worst case. I\'m taking them to my mechanic Uwe today for some help. I\'ll make sure they all fit together before shipping them.