Borg Warner T10 vs Toploader
 

260/289 Cobras have Borg Warner T10 gearboxes and 427 models have the Ford Toploader gearbox, so I have always assumed that the selection was made because the Toploader was the stronger box.
However....I was reading in Greg Kolasa's book on Shelby Mustangs that close-ratio BW T10 gearboxes were fitted to Shelby Mustangs on the Ford production line, rather than the Ford Toploader box fitted to non-Shelby manual transmission Mustangs (this is 1965, so no BBF under the Mustang hood)
I had always thought that the Toploader was the stronger gearbox, so why did Shelby specify the T10 instead of the Toploader? I think the ratios available to both were the same or similar. Was the T10 chosen because it was lighter (I'm guessing here....) or what was the story?

Cheers,
Glen

I don't know why but the T10 they used in the Shelby was aluminum case so the weight factor is probably a good guess. Interesting but I think Ford installed Toploaders in similiar, non-Shelby Mustangs at the same time.

Yes I agree, the T10 housings going into GT350s were aluminium, and yes the standard Mustangs going down the same line, with the same engine fitted, were fitted with Toploaders.
Can anybody comment on the torque capacity of both gearboxes?
Cheers,
Glen

I doubt that anyone ever tagged them with a specific power or torque capacity back then. I would think the Toploader could handle more torque than a regular T10 - at least with the big input/output. I wasn't until the Super T10 came out that it was regarded as a HD transmission.

With the exception of the GM Saginaw 4 speed, the T-10 is the weakest 4 speed on the planet. If you have decent power and a little bit of traction, the main shaft will twist just ahead of the yolk. I've rebuilt many of them and would conservatively say that 90% had twisted main shafts. Another weak point are the synchros. Unless you rebuild them using Torque-Lok sliders, you're guaranteed they will jump out of gear on deceleration. They are okay for a cruiser but I wouldn't put one in anything I planned on "driving hard".

...hence my surprise that for a car that was to be raced, a T10 was specified over a Toploader.

Dear all,
sorry to reopen another old thread.

But I would be deligthed if once and forever the question regarding which gearbox type/specification was used on which original MKII could be solved.
I am speaking standard specs.

? Is it Borg Warner T-10 "M" (Cobra registry says) or "L" (some literature says) or something else???
Or did they change from #2126 onwards for even different codes??

? Always iron casing? (I understand alloy casing as option, says some literature?)

? How do later T10 differ from the earlier ones?

I hope some one can clear this. It is really hard to understand even reading through lots of books on the subject.

Toploader came later I believe, evolution if you will

I am by no means a Cobra transmission expert but the expert had helped me and many other original Cobra owners. Cobras used a variety of T10 models. His notes are pages long. Short version.

Design wise think 1963-64 289 Ford Galaxie T10 physical dimensions. Early transmissions included cast iron main cases and tail shaft housings. After Ford created the aluminum main cases and tail shaft housings for the “lightweight” Galaxies, Cobras started using aluminum main cases and tail shaft housing. In the aluminum cases units more than one gear set was available, standard ones used Ford design all the way while a racing option used a GM input. When the GM input was used the engine installers had to remove the clutch disc Ford installed and replace it with a GM disc. Some street cars received GM input gear sets, my black car is one of them.

The aluminum tail shaft housings tended to break in any kind of competition so SAI sometimes replaced aluminum tail shaft housings with cast iron ones. They did this for their team cars sometimes and offered new transmissions fitted that way to independent racers.

A common point of confusion is the main case front flange. Cobras used five bolt engine blocks so their transmissions had the early narrow bolt pattern. 1965 and later Fords used six bolt engine blocks so a different aluminum main case was required for 1965-66 MUSTANG GT350s.

Tables don't paste in well so this will be jammed left.

B close (1962)* L & J close** M close*** K close (GM)****
1 36 1 36 1 36 1 36 (GM 1358577/Ford C3AZ-7100-F/BW T10-E12)
2 32 2 30 2 29 2 30 (GM 1358579/Ford C3AZ-7102-E/BW T10-E31)
3 29 3 29 3 27 3 29 (GM 1358576/Ford C3AZ-7B340-A/BW T10-E11)
4 26 4 26 4 26 4 27 (GM 9771377/BW T10-K16)
C 29-23-20-17 C 29-23-19-17 C 29-25-20-17 C 28-23-19-17 (GM 9771378/BW T10-K8)

* The B gear set was used on early Cobras.
** L gear sets are nickel alloy, J gear sets are not and the J sets were used in Hi Po 289 Fairlanes
and 390 Galaxies.
*** The M set is nickel alloy and also called the "Sebring" gears and was first available in 1964.
**** The K close ratio gear set is a nickel alloy gear set originally used in GM cars (Pontiacs) from 1957 to 1963 and it was used in some HP289 powered Cobras. A GM clutch disc is used because the GM input shaft diameter is larger. 1st, 2nd & 3rd gears in the K set are the same as used in the L ratio gear set.



Transmission case material. Not the documentation you would like but Dick Roush has known CSX2115 and CSX2165 since the 1960s he told me. CSX2115 had an iron case unit and CSX2165 had an aluminum case unit. The street car implementation date and or chassis of the family of aluminum cased transmission assemblies (more than one gear set version) is not known. Based on SAI photos for FIA registration the first LeMans Replica race cars in the CSX213x range received transmissions with aluminum main cases and tail shaft housings.

Thanks Dan! :D

Dear Dan,
thanks as always!

I knew this chart from wasaac.org. What remains unclear is:

"B" gear sets are asid to be used in 260s and early 289s - but until which date? They were steel casings, correct?

"J" gear sets used potentially again in 260s and early 289s -> can we asume that there is no record on which car had which type?

Most importantly: Common literature knoweldeg seems to be most 289s used "M". Except "M" (Sebrings) were first available late 1963 only. That would mean around CSX2240?


Sorry for picking on this topic. But today so many 289s are described as "period correct t10 gearbox". I think that is not enough, if we consider for what period T10s had been built!!

Quote:

Originally Posted by Dan Case (Post 1416614) I am by no means a Cobra transmission expert but the expert had helped me and many other original Cobra owners. Cobras used a variety of T10 models. His notes are pages long. Short version. Design wise think 1963-64 289 Ford Galaxie T10 physical dimensions. Early transmissions included cast iron main cases and tail shaft housings. After Ford created the aluminum main cases and tail shaft housings for the “lightweight” Galaxies, Cobras started using aluminum main cases and tail shaft housing. In the aluminum cases units more than one gear set was available, standard ones used Ford design all the way while a racing option used a GM input. When the GM input was used the engine installers had to remove the clutch disc Ford installed and replace it with a GM disc. Some street cars received GM input gear sets, my black car is one of them. The aluminum tail shaft housings tended to break in any kind of competition so SAI sometimes replaced aluminum tail shaft housings with cast iron ones. They did this for their team cars sometimes and offered new transmissions fitted that way to independent racers. A common point of confusion is the main case front flange. Cobras used five bolt engine blocks so their transmissions had the early narrow bolt pattern. 1965 and later Fords used six bolt engine blocks so a different aluminum main case was required for 1965-66 MUSTANG GT350s. Tables don't paste in well so this will be jammed left. B close (1962)* L & J close** M close*** K close (GM)**** 1 36 1 36 1 36 1 36 (GM 1358577/Ford C3AZ-7100-F/BW T10-E12) 2 32 2 30 2 29 2 30 (GM 1358579/Ford C3AZ-7102-E/BW T10-E31) 3 29 3 29 3 27 3 29 (GM 1358576/Ford C3AZ-7B340-A/BW T10-E11) 4 26 4 26 4 26 4 27 (GM 9771377/BW T10-K16) C 29-23-20-17 C 29-23-19-17 C 29-25-20-17 C 28-23-19-17 (GM 9771378/BW T10-K8) * The B gear set was used on early Cobras. ** L gear sets are nickel alloy, J gear sets are not and the J sets were used in Hi Po 289 Fairlanes and 390 Galaxies. *** The M set is nickel alloy and also called the "Sebring" gears and was first available in 1964. **** The K close ratio gear set is a nickel alloy gear set originally used in GM cars (Pontiacs) from 1957 to 1963 and it was used in some HP289 powered Cobras. A GM clutch disc is used because the GM input shaft diameter is larger. 1st, 2nd & 3rd gears in the K set are the same as used in the L ratio gear set. Transmission case material. Not the documentation you would like but Dick Roush has known CSX2115 and CSX2165 since the 1960s he told me. CSX2115 had an iron case unit and CSX2165 had an aluminum case unit. The street car implementation date and or chassis of the family of aluminum cased transmission assemblies (more than one gear set version) is not known. Based on SAI photos for FIA registration the first LeMans Replica race cars in the CSX213x range received transmissions with aluminum main cases and tail shaft housings.

Case Material
Between SAI and Mr. Roush’s research the mystery time frame is roughly between when “iron” CSX2115 was completed (June 1963) and “aluminum” CSX2136-2138 (about August 1963). From your first post today I don’t think CSX2126 would be in the discussion because it was finished at AC Cars before CSX2080. Circa early February 1963 CSX2126 was a running car.

Gears
I just called Dick Roush. Dick has helped find parts and coordinate shop work of many Cobra owners repairing or rebuilding their original transmissions. As far as he recalled:

B sets = only in the iron cased Galaxie transmissions that happened to get redirected to new Cobras

J sets = he does not recall finding a J set in a genuine Cobra transmission, he allowed that it could have been possible but doesn’t recall any.

L (high nickel) sets = aluminum cased Cobra transmissions

K (high nickel) sets = aluminum cased Cobra transmissions introduced sometime in the CSX22xx range, example he knows CSX2246 had a K set originally, my black car CSX2310 was fitted with a K set.

M (high nickel) sets = aluminum cased Cobra transmissions introduced sometime in the CSX23xx range, his belief was that the later the chassis was the more likely it was fitted with a M set.

The tough part to deal with is chassis were not finished in order so it is meanless to think that since car CSX2xxx was fitted with "such and such" that chassis CSX2xxx±1 or 2 or whatever got the same part or assembly. Case in point AC Cars wise CSX2126 was finished at AC before CSX2080 was completed at AC. CSX2126 was rushed to SAI ahead of other chassis so even at SAI it was running much earlier than any other cars numercialy close to it.

I believe I heard CS say that SAI used Pontiac gears in the race car transmissions. Can you shed any light...

Sorry no. I used to hear that decades ago myself, more specifically different gear sets were used for different venues along with different diameter rear tires and differential gear ratios. Most of the Cobra transmission information I have comes from Dick Roush. He can quote Ford, BW, and GM part numbers for all the sets without having to look them up usually.

The Feb. 6, 1964 reconfirmation of what was submitted to the FIA (with pictures of CSX2138 and the first Daytona Coupe included) shows L gear ratios standard and K ratios as an alternative. The M ratios are not listed at all on that document. SAI was into finishing late CSX22xx and early CSX23xx chassis at the time.

My black car (CSX2310, end of March 1964) came with a K set and I really like the ratios. Back when I use to run open track events at Hallet the car did extremely well on that short course. Extremely well means it was gears wise better for that track than any of the other Cobras running at the same time.

People working on Cobras with K sets can get real frustrated trying to make a Ford specification clutch disc slide onto the splines, they won’t. I know of a few main cases that got broken as people tried to force a transmission in place using the mounting bolts to attempt to make the transmission pull up into place. Won’t work, the ears on the transmission snap right off. I have heard of owners ditching K sets and installing M sets so they won’t have to worry about getting the correct clutch disc design again.

That would explain why I never was able to find a Pontiac T10.

So where did the GM input gear sets come from?

Dick's only comment, "The K close ratio gear set is a nickel alloy gear set originally used in some 1957- 63 GM high performance cars."

Maybe that meant Corvette T10 ?

GM gear sets probably came from 409 or Corvette applications if they were used, the book below references gear sets sourced from Pontiacs. The book I have was printed in period (circa 1964) that was authored by Bill Carrol. There are gear ratios referenced in this book also.
I have an early cast iron T10 that belongs to a 20XX Cobra that I am restoring, maybe I'll pull the side cover and check the ratios.

You are my hero!

I think today we can just try to be as accurate as possible and have "Likely atches of VIN sequences".
In any case that means if you have a "M" on a 1962 car, it very likely means it is correct type, but not the exact one.

Last question: The cast iron were Grey or "Ford blue"?

Ford transmissions are always natural when new, they did not paint them. And "Ford Blue" was not introduced until 1966 model year production.