History: Of the 3,935 Ausf H chassis produced, 3,774 were completed as Pz Kpfw IV, with 30 used for the first StuG IV and 130 for Brummbar. In November 1943, an attempt was made to alter the suspension to gain ground clearance. The experiment failed and the Pz Kpfw IV retained the same basic suspension from 1937 until the end of the war.
Specific features: The basic change from the Ausf G was the SSG77 transmission fitted to the Ausf H. The frontal armour on the Ausf H evolved from 50mm basic with 30mm additional, to 80mm basic, to 80mm basic interlocked with the hull sides. Minor modifications, introduced during the production run of the Ausf H, included external air-filters, all-steel return rollers, a cupola mount for an antiaircraft machine gun, a new style idler, and the deletion of the side vision ports for the driver and radio operator.
Combat service: From 1943, Panzer regiments in the Panzer divisions were to have one detachment equipped with Pz Kpfw IV and one detachment with Panthers. As a result of problems with the Panther, some Panzer divisions had a second detachment equipped with Pz Kpfw IV, while many had but a single detachment of four companies, each equipped with twenty-two Pz Kpfw IV, plus eight with the HQ Company. On 6 June 1944, most of the 748 Pz Kpfw IV with the nine Panzer divisions in France were Ausf H.
History: The Ausf J was the last series of the Pz Kpfw IV and was produced solely by Nibelungenwerke after Krupp had been switched to the StuG IV, and Vomag to the Jgd Pz IV. In addition to the 1,758 Pz Kpfw IV, 278 Ausf J chassis were used for Panzer IV/70(A) and 142 chassis were built for conversion to Brummbar.
Specific features: The main change introduced with the Ausf J was the elimination of the electric traverse and its associated auxiliary engine. A dual gear-ratio hand-traverse was fitted in its place, and the space previously occupied by the auxiliary engine was used to increase the fuel capacity. The armour thickness of the turret roof was increased and a 'Nahverteidigungswaffe' added as a smoke projector and for close defence. Minor improvements introduced during the Ausf J production run included the deletion of pistol ports and vision ports from the turret rear and side doors, wire-mesh 310 skirting on the hull sides, 3 instead of 4 return rollers, steel-tyred road wheels, vertical exhaust mufflers, and the hull sides extended beyond the front hull plate, and drilled to provide holes for towing shackles.
Combat service: As a result of combat attrition and loss of production through bombing, the number of Pz Kpfw IV per Company by official organization was cut back to 17, 14 or 10 in November 1944. Thus the Panzer divisions taking part in the Ardennes offensive had only 26 to 42 Pz Kpfw IV. A total of only 259 were on hand with eight Panzer divisions taking part in the offensive. During the war, Pz Kpfw IV had been furnished to Bulgaria, Croatia, Finland, Italy, Spain, Rumania, Turkey and Hungary.
History: The Sturmpanzer was developed by Alkett, who designed the superstructure, and Krupp, who altered the design of their Pz Kpfw IV chassis. On 20 October 1942, after seeing Alkett's plans, Hitler demanded that forty to sixty Brummbar be built as soon as possible. On 7 February 1943, it was decided that the forty must be completed by 12 May 1943, with a following production run of twenty. After this initial run from April to May 1943, the production of a long-term series went ahead in November 1943 and continued until the end of the war.
Specific features: The Brummbar had a box-like superstructure, housing the 15cm StuH43, mounted on a normal Pz Kpfw IV chassis. The first series was mounted on fifty-two new Pz Kpfw IV Ausf G chassis plus eight rebuilt Ausf E and F chassis. Instead of the 80mm armour on the hull front, the first sixty had a 50mm armour plate bolted to the basic 50mm hull front. This first series had a sliding-shutter visor for the driver, similar to that mounted on the Tiger I. In the later series, the driver was provided with a periscope and an StuH431 was fitted. The final series, produced from June 1944, had a redesigned superstructure with a ball-mounted machine-gun in the top right-hand corner of the front plate, and a cupola for the commander.
Combat service: Sturmpanzerabteilung 216 was issued with the first Brummbar, and was rushed off to the Eastern front for the summer offensive at Kursk. This unit was also active in defensive battles near Zaparozhye up to October 1943. Three additional Sturmpanzer detachments (217, 218 and 219) were formed during the war, and fought on the major eastern and western fronts, and also in Italy.