"Transformé" Sherman tanks


By the final months of World War II, the power plants of many of the French Army's Sherman Medium Tanks had worn out, and replacements were requested. The only engine that was readily available from the US was the Continental Radial. A late war report from a US Liaison Officer described the steps necessary to replace the M4A4's original Multibank Engine with a Radial. Other than this single test fit, it is believed that further engine replacements were done in the years after WW II. In the absence of any "paper" documentation, we have gathered clues from approximately 30 surviving Shermans in Europe regarding the details of the process. At present, all of the examples identified have been M4A4s, so it would seem that the engine exchange was limited to this single model. On a few surviving M4A4s, a "new" identification plate has been seen affixed to the wall to the left of the driver's seat, right next to the tank's original dataplate. The top line seen on the ID plate shown above reads "CHAR M4A4T - MOTEUR CONTINENTAL," with the "T" standing for "Transformé."

M4A4T plate location

The French received 274 M4A4s as Lend Lease. In addition, a small number, perhaps less than 50, former British/Commonwealth M4A4s (Sherman Vs) were passed on to them in early 1945. Based on our study of the M4A4Ts, we suspect that the French must have collected up more from European tank dumps in the post war years. In order to accommodate the massive 30 cylinder Chrysler Multibank engine, the M4A4 was made 11 inches longer than the standard Sherman. The Multibank with its front mounted radiator (position 1) was so large that there was no room for vertical fuel tanks in the front corners of the engine compartment, such as were present on Radial engined M4s and M4A1s. However, the elongated hull enabled the sponson fuel tanks (positions 2) to be enlarged to hold 80 gallons each. Thus, the two fuel tanks of the M4A4 held 160 gallons, versus the 175 gallon capacity of the four fuel tanks on M4s and M4A1 Shermans. There might have been room for them, but the examination of a few M4A4T wrecks suggests that no vertical fuel tanks were added, so that the Transformés retained the M4A4's 160 gallon capacity. We would note that the fuel tanks of M4s, M4A1s and M4A4s suffered in common from an excessive heat condition, which caused melted solder joints and other fire hazards. This was remedied by the addition of a pair grouser compartment covers with air inlet grills (3) that provided for greater air flow to the fuel tanks.

M4A4T plate    M4A4T plate location

Aside from the interior ID plate, some of the M4A4Ts examined have been noted to have "Rebuild" plates. These have been seen welded to the tank's exterior. In some cases, they have been found in three places on the same tank - affixed to the front and rear of the hull, as well as on the top of the turret. Of course in many instances, the plates have long since rusted away or have been removed. The photo on the left shows what is typically printed on one of these plates. The right side photo shows the "usual" location of the front plate as noted on M4A4 Serial Number 22169, a monument Sherman on display in Avranches in Normandy. The plate's first line reads "A R L," which indicates that the tank was "transformed" at the French Army Facility known as "Atelier de construction de Rueil." Evidence found on the ARL plates suggests that the Transformé Program took place in the early 1950s. We would note that other non M4A4T French Shermans have been observed with rebuild plates or stampings from other facilities, including "A B S," (Atelier de construction de Bourges) and "ERGMEB" (Etablissement de Réserve Générale du Matériel - Engins Blindés).
A translation of the plate above:
A R L (Atelier de construction de Rueil)

Char D57 (Thought to be the Serial Number of this particular M4A4T)
DATE 9.12.52 (9 December 1952, the date the M4A4T rebuild was accepted)

M4A4T serial   
M4A4T serial

It is thought that the French Army stamped the Ordnance Serial Number on most or all of the AFVs used in service in the post war years. This has been recorded from quite a few surviving Shermans tanks, to the extent that we refer to it informally as "the Serial Number inside a box." This stamping is not always exactly in the same place. Anyone wishing to see it is advised to look around on the front of the tank. While the SN stamping is not exclusive to the M4A4Ts, it has been noted on almost all surviving examples.

M4A4 engine deck    M4A4T engine deck

The photo on the left shows the typical M4A4 engine deck configuration. The forward sections include an air intake grill (1), and a cast armor blister (2) which protected the Multibank engine's oversize radiator. The middle section of the deck (3) was hinged, and could be lifted by means of a pair of handles in order to provide engine access. The rear section (4) was not removable, but permanently welded to the hull. The photo on the right shows the same view of an M4A4 after the Transformé engine swap. As best we can tell, the conversion retained the M4A4's middle engine deck plate (3), and simply replaced the forward sections with the forward section of an M4/M4A1. The air intake was protected by a large armored cover (5), and this in turn was protected by a surrounding bullet splash (6).

M4A4T engine deck

One might assume that the M4A4T's forward engine deck section was salvaged from surplus or obsolete M4s or M4A1s. That might have been the case on some, although we have not as yet encountered such an example. The twelve surviving M4A4Ts that we have seen that still have this section, are installed with what appear to be aftermarket components that seem to have been fabricated by a French firm specifically for the Transformé program. From personal examination we would judge that the entire "French" plate is a casting that includes the bullet splash surround. In contrast, the standard M4 or M4A1 forward engine deck section was an armor plate with the bullet splash welded on to it. The "French casting" features five additional bolt holes directly behind the bullet splash. These are NOT present on the standard US engine deck section. On 11 out of 12 examples examined so far, the "French" bullet splash is indented in order to accommodate three of the bolts. The examination of a few survivors reveals that these additional bolts held a baffle plate (inset) to the underside of the forward engine deck. The armored air intake covers have casting marks not seen on any of the same US produced intake covers we have encountered. Like the standard 1944 US produced version of this plate, there are no fuel filler locations on either side of the air intake opening (marked by Xs). We have also noted that there are six bolts along the sponson edges, as opposed to four on the standard US radial deck. Finally the hinges, with their slotted bolt heads are aftermarket parts, as they are not original to M4, M4A1 or M4A4 Shermans.

M4A4T engine deck    M4A4T engine deck

The photos above show the casting marks on two of the armored air intake covers. We would speculate that the name of the foundry that cast these pieces might be represented by the letter "C,” possibly CAIL (« Société française de constructions mécaniques (SFCM), » also known as « Anciens Établissements Cail ») the firm whose name is seen on the hull casting of the Somua S-35.  “No" might be for "numéro," and pertain to the serial number of the individual casting –  thought to be 3 on the left and 161 on the right. The part number or "numéro de pièce" would be the same on all of the castings, and looks to have been "64688." For comparison, the part number of US WW II produced intake covers is D51304, and has been seen cast on the underside, as in the inset. The dates that the French parts were cast appear to be 1 51 (January 1951) and 3 52 (March 1952), and provide something of a clue regarding the chronology of the Transformé program.

M4A4T engine deck    M4A4T engine deck

The above shows comparison shots of the reproduction radial engine deck of an M4A4T on the left, and an original radial engine deck of an M4(105) on the right. On first inspection these decks are almost identical in appearance, although the Transformé’s replacement deck does NOT include the additional engine oil filler cap (1) seen on Second Generation M4s& M4A1s. As noted above, the major identifier that the M4A4T’s deck is not a salvaged radial engine deck are the three indents (2) seen here, which allowed the fitting of the additional bolts. In some cases, the indentations are very subtle, and don’t show up in photos, but have been noted during “hands on” examinations. We can also see the welds attaching the bullet splash rail to the original deck (3), these welds not being required on the Transformé’s one piece casting. Another difference is that there are two bolts securing the forward edge on both sides of the air intake in the US configured deck (we’ve circled in red one of the bolts). These bolts are not present on any of the Transformé replacement decks we have examined. Also note the difference in location of the engine crank holes (4).

M4A4T engine

It is thought that the French received a number of replacement Continental R-975 engines as "Spare Parts" for the approximately 1500 radial engined M4(105)s and M4A1(76)s that they were issued as Mutual Defense Assistance in the early 1950s. These crated engine kits appear to have included a number of additional items including new instrument panels, air cleaners with all the necessary piping and fittings, and the Barber-Colman type of exhaust deflectors. The air cleaners (1) and the centrally mounted exhaust pipes (2) were adapted to fit the M4A4 hull. Although we have not encountered any surviving examples that still have it present, it is evident that the exhaust deflector was installed as indicated by the fittings (3) that secured it in the "down" position, as well as the fitting (4) which secured it in the "up" position in order to provide access to the engine doors (5).

M4A4T hull

About a half dozen of the surviving M4A4Ts have been recovered from Military Target Ranges. A few examples are very badly damaged, and have been reduced to hulks, missing so much that a proper ID is difficult.  In the case shown above, the primary clue that this was an M4A4T is the oblong engine crank hole (1) that was drilled or ground into the top center of the M4A4’s upper rear hull plate. Only Radial engine Shermans used a hand crank as part of the engine start up procedure. On Radial airplanes, a crewman would spin the propeller a few times so as to test for hydrostatic lock. On the radial Sherman, Step 1 of the start up procedure was, “Have engine turned over four complete crankshaft revolutions by hand (about 50 turns of the hand crank).” This would work to expel any excess fuel or oil that may have accumulated, particularly in the combustion chambers of the cylinders closest to the ground. A secondary M4A4T clue seen here is the fitting (2) that secured the exhaust deflector in the "up" position. The two 80 gallon fuel tanks of the M4A4 are missing from this hulk, but they sat on the sponsons in the area indicated by the number 3.

M4A4T hull

Atelier de construction de Rueil would have had to have provided a hand crank for each M4A4T, either fabricated in house or salvaged from a surplus M4 or M4A1. The photo above shows a restored example on display at Camp de Mourmelon in France. The hand crank (1) seen here, along with the track wrench (2), do NOT reflect the appearance of the same original equipment tools supplied in the US. It is not known if the crank was made during the Transformé program, or fashioned in later years for the display. We would note that the position of the hand crank fittings corresponds to what has been observed on other M4A4Ts. Also of note are the fittings with reflectors attached (3). These (or their weld scars) have been observed on most or all surviving M4A4Ts, so it is thought that they were added as part of the conversion process. This tank is Serial Number 4825. It would have been accepted in August, 1942, and is at present the earliest surviving M4A4 that we have recorded. It has the look of one of the 1610 M4A4s remanufactured by Chrysler, and supplied to the British as Lend Lease in 1944. Despite the fact that the French received 274 M4A4s as Lend Lease, a surprising number of the surviving M4A4Ts are remanufactured, former British/Commonwealth Shermans. We would assume that they were salvaged from post war Tank Dumps.

M4A4T turret    M4A4T turret

The commander's "split hatch" cupola was installed as original equipment on all new production and remanufactured M4A4 Shermans. The study of surviving M4A4Ts suggests that it was replaced with the "commander's vision cupola" (1) during the conversion process. The transition to the improved cupola on new production Shermans was completed in May, 1944. In addition, a Modification Work Order ((MWO G104-W112) kit was released in September, 1944. It was to be retrofitted to all "medium tanks of the M4 series located in overseas theaters of operation or those scheduled for overseas shipment." These cupolas were greatly superior to the old split hatches, and were in high demand in combat zones. However, in the end, very few of the approximately 10000 kits produced were shipped overseas for field installation before the end of WW II. About 1300 of the kits were retrofitted to Shermans remanufactured in 1945. Thus, thousands of the kits would have been available as "new old stock" after WW II, and it is thought that the French received some as MDAP "Spare Parts" in the early 1950s. The kit also included parts for an Anti-Aircraft Machine Gun Pintle Assembly (2), and a vane sight (3 and inset) to replace the old blade sight (4). Additionally, instructions were provided for relocating the commander’s seat bracket, "to permit tank commander to look through vision blocks while seated."  One of the final instructions in the vision cupola modification kit is "Install cal. .50 antiaircraft machine gun stowage brackets (5) on back of turret in accordance with  MWO G104-W108, if vehicle is not so equipped." Thus, these two modifications were to be installed together. It is thought that the French received some of the MG stowage kits as well, since this mod is installed on many of the turrets along with the commander's vision cupola.

M4A4T siren

From start to finish, Chrysler M4A4s, including the 1610 units remanufactured from December, 1943 though October, 1944, were built with a siren factory installed on the left front fender as shown in the upper left. The siren most commonly used on the M4A4 was the Federal Type 160 with the "V for victory" grill (1). Power was supplied by conduit, and the coupling (2) is often all that remains on many surviving Shermans. It is evident that the siren was relocated with the M4A4T conversion, since surviving examples show the siren mounted on a pad on the left front of the glacis plate just below the hull lifting ring. The sirens are long since gone on most of the extant M4A4Ts, but a mounting pad (3) remains. The presence of this pad on a surviving M4A4 is almost invariably a clue of a Transformé conversion. A siren guard (4) was fabricated, which on some hulls, is seen with wire mesh welded to its face. We would note in passing that a few M4A4Ts and other French rebuilt Shermans have a siren with stars around the faceplate (5).

M4A4T siren    M4A4T siren

The stars around the faceplate are not typical of any of the various US produced sirens supplied to Sherman manufacturers. This siren was made in France, probably during the late 1940s or early 1950s, by Cicca (Compagnie Industrielle et Commerciale du Cycle et de l’Automobile), an auto equipment and accessories manufacturer based in Neuilly-sur-Seine, near Paris.

M4A4T siren

Non standard mudguards (or traces of them) are seen on the rear of many of the M4A4Ts (1), so it is thought that they were added as part of the Transformé conversion. This M4A4 is Serial Number 21752, indicating that it was accepted in July, 1943.  The “no pistol port turret” was introduced in production at Chrysler in July, so the turret, if not the original, is appropriate. This tank is on display as a monument in Chavannes-le-Grand, France, and honors “Foch” an early 1943 production M4A4 of the 1er Régiment de Chasseurs d'Afrique, 5ème Division Blindée, that was knocked out there on November 23, 1944.

M4A4T siren

The French received large numbers of Armored Fighting Vehicles from the US as Military Assistance in the early years of the 1950s. Almost 3000 Medium Tanks were supplied. Aside from the close to 1500 Shermans mentioned earlier, 544 M26 Pershings and 854 "M46, M47, M48 Series" Pattons were reported to have been shipped as of January 31, 1954. Given that, it is somewhat surprising that the French would have needed to do the Transformé conversions at all, much less obtain more M4A4s from British/Commonwealth post war surplus. Considering that M4A4Ts represent a good number of the surviving M4A4s in France, we are somewhat frustrated in not having been able to find any period photos of them in French service. This leads us to suspect that they may have been intended for “off the books” export to Israel in the tense years before the outbreak of the Second Arab-Israeli war in October, 1956. It is obvious that the Israelis procured a number of ex British and French M4A4s, and a few sources state that some were Transformes. We can only observe that a small number of period photos, such as the above, taken in September, 1954 during an IDF Training Exercise in the Negev Desert, show what appear to be M4A4Ts with the “indents” characteristic of a French made forward engine deck section. This tank can also be seen with the exhaust deflector fitting (1). The surviving M4A4Ts in France (that have turrets) are equipped with the commander's vision cupola (2), but none that we have examined have retrofitted loader’s hatches (3) as seen on this example. So perhaps that and the VVSS track holders (4) were added by the Israelis? We would observe in passing that, while Foch from the preceding caption has a “no pistol port turret,” the turret on this example has a welded up pistol port (5). The decision to eliminate the pistol port in mid 1943 was universally unpopular, and it was reinstated in production in late 1943, coincident with the introduction of the loader’s hatch. A few surviving IDF Shermans actually have turrets that were painstakingly retrofitted with pistol ports, such as the M50 turret shown in the inset.

M4A4T siren

“First Generation” Shermans with 75mm guns were still in combat use during the 1956 Sinai Campaign. It is thought that a number of these would have been M4A4Ts with retrofitted loader’s hatches such as seen on the example in the previous caption. None of these appear to have been preserved by the Israelis, possibly because some or all were ultimately upgraded to the “legendary” M50 configuration. In that regard, some French made M4A4T engine deck components appear to have been recycled for reuse when Israeli Shermans were retrofitted with Cummins Diesel Engines. On the top left is shown the French type casting marks on an armored air intake cover half of an M4A4 based M50. On the bottom left are the “French indentations” on the bullet splash halves on another M4A4 based M50. On the right, we see both the indentations (arrow) and the French casting marks (circled in red) on an M4A1(76) based M51. Of course, an M4A1 would have been built with the appropriate forward engine deck components, but this example illustrates how original parts were not necessarily reinstalled on their “mother” vehicles. Note that the intake cover halves on the M50s on the left used only the original hinges, so each half is attached with a single hinge. On the M51’s deck, the original hinges can be seen to have been cut off, and two new hinges/fittings were added to each half, perhaps for greater stability. Photos and info courtesy of Tom Gannon.