Banjo Differential
From Holdenpaedia
Original submission by T Apr 5th 2007:
Back to Gearboxes Transmissions and Differentials
Contents |
[edit] Banjo Differential:
A Banjo Differential has the gearset built into a removable centre in the rear axle housing. Note that the diff centre is held in the axle housing by a series of studs that look like the drum tuning keys on a banjo.
Thread1
9 Inch Banjo Thread
A Banjo diff does not have a removeable tinplate cover on the rear of the axle.
[edit] Ratios:
if the car is original and you can guarantee it has the original diff you could go off the body ID plate under the bonnet.
However if someones replaced the diff at some stage it may have a different ratio.
Look for the plate under the bonnet on the cowl with ENG TRANS RRAXLE down the bottom. compare the code next to RRAXLE to these:
GU4 = 3.08:1
GU7 = 2.78:1
GU8 = 3.90:1
GV2 = 3.36:1 (V8 HQ's Only)
GV4 = 3.36:1
GV7 = 3.55:1
G70 = 2.60:1
GM9 = 4.44:1
[edit] LSD:
Limited Slip Differentials have been made in either Banjo or Salisbury form.LSD
[edit] Banjo Advantages:
Their advantage is that they are easy to replace.[edit] Banjo Disadvantages:
Their disadvantage is that they rotate and break axles under high torque. |  |  |  |
 |  |  | |
| |  |
[edit] Ratios:
crownwheel.
2.78 and 3.08 share a common centre. Their centre requires 2 long studs on the driver's side. The other diffs use only short studs and nuts.
Note that Banjo Carrier bearings are bolted to the removable centre. When enough tailshaft torque
is presented to them the whole banjo centre can rotate and cause an axle breakage as in the famous Bob Morris 1976 L34 Bathurst 1000 win.
Only that the car had a Limited Slip Differential was power still provided to the unbroken axle which allowed him to cross the finish line.
[edit] Salisbury:
A Salisbury Rear Axle solves the rotating centre that Banjos have by placing the carrier bearingsin the axle housing rather than in the removable centre.
The diff is built into the axle rather than into a removable section.
[edit] Rear Axles:
Note that there are coarse and fine spline axles.[edit] Coarse Spline Axles:
The coarse spline axles have the fewest teeth and are the early type. These were prone to breaking. [edit] Fine Spline Axles:
The fine spline axles have the most teeth and are the later type. These solved the axle breaking problem.
[edit] Diff Change:
Note that when changing the differential the axle type must be observed. Changing the side gears inside the differential is a quick job for a diff ace and can make it easy to match axle type to the side gears.
[edit] 9 Inch:
A 9 inch is a type of Banjo diff that has been toughened considerably.
 |  |  |
[edit] Historical:
This is axle portrayed is not a traditional "Banjo" rear end. This is more like a "8"" type floating axle "modern" rear end. Typically, a banjo rear end is a 29-41 Ford (Merc) with two identical "bells" (look like trumpet bells) which bolt on each side. The axles are retained by the differential and axles drive unique brake drums through a tapered end of shaft square key which fits in slot on both hub and drive shaft. They are easy to identify by the center section/bell symmetric shape. The classic hot rod look uses the Halibrand, Winter or other center sections modified for quick change gears (used originally for racing) and can be (when fully modified to floating axles) be quite robust.
Regards;
Gregg (31 Coupe/PontiacV8/banjo in process) Schluntz
T adds - The diffs portrayed in this page are what GMH refers to as Banjos.
[edit] Links:
