Jack attachment and method of transmission removal

A novel attachment for a motor vehicle transmission jack of the type having a lift arm adapted to raise and lower motor vehicle transmission parts at its forward end. The attachment is adapted to support a fully assembled 4-wheel drive transmission unit, including the transfer case and the motor vehicle transmission support bracket, independently of a motor vehicle. The attachment includes a base member adapted to be connected to the forward portion of the lift arm and having a support portion adapted to supportably engage the motor vehicle transmission support bracket substantially vertical of the forward end of said lift arm. The attachment also includes a forward support member rigidly secured to the base member, having a support portion adapted to supportably engage the forward portion of the transmission. The support portions of the base member and the forward support member are spaced relative to each other to support the motor vehicle transmission unit in a substantially horizontal position. The method of removing a fully assembled 4-wheel drive transmission unit, including the transfer case and the motor vehicle transmission support bracket, from a motor vehicle utilizing this type of transmission jack and attachment includes positioning the jack under the transmission unit. The method further includes activating the jack to substantially simultaneously supportably engage the motor vehicle transmission support bracket and the forward portion of the transmission, disconnecting the transmission unit from the motor vehicle drive train and disconnecting the motor vehicle transmission support bracket from the motor vehicle.

BACKGROUND OF THE INVENTION 
This invention relates to an attachment for a motor vehicle transmission 
jack and more particularly to such an attachment adapted to support 
4-wheel drive transmission units independently of the motor vehicle during 
removal and installation as well as repair. 
Repair of model 350 and 400 turbo hydromatic transmissions for 4-wheel 
drive vehicles such as 1973 through 1978 half and three-quarter ton 
Chevrolet and GMC trucks has required removal of the transmission from the 
vehicles themselves. Instructions issued by the manufacturers of these 
vehicles direct that transfer case be removed separately from the 
remainder of the transmission unit. Accepted time for such removal and 
installation using the foregoing method has ranged from four to five and 
one-half hours; utilizing the novel attachment and method of this 
invention, the time for removal and installation is reduced to about two 
hours. 
SUMMARY OF THE INVENTION 
The present invention relates to a novel attachment for a motor vehicle 
transmission jack of the type having a lift arm adapted to raise and lower 
motor vehicle transmission parts at its forward end. The attachment is 
adapted to support a fully assembled 4-wheel drive transmission unit, 
including the transfer case and the motor vehicle transmission support 
bracket, independently of a motor vehicle. The attachment includes a base 
member adapted to be connected to the forward portion of the lift arm and 
having a support portion adapted to supportably engage the motor vehicle 
transmission support bracket substantially vertical of the forward end of 
said lift arm. The attachment also includes a forward support member 
rigidly secured to the base member, having a support portion adapted to 
supportably engage the forward portion of the transmission. The support 
portions of the base member and the forward support member are spaced 
relative to each other to support the motor vehicle transmission in a 
substantially horizontal position. 
The method of removing a fully assembled 4-wheel drive transmission unit, 
including the transfer case and the motor vehicle transmission support 
bracket, from a motor vehicle utilizing this type of transmission jack and 
attachment includes positioning the jack under the transmission unit. The 
method further includes activating the jack to substantially 
simultaneously supportably engage the motor vehicle transmission support 
bracket and the forward portion of the transmission, disconnecting the 
transmission from the motor vehicle drive train and disconnecting the 
motor vehicle transmission support bracket from the motor vehicle.

DESCRIPTION OF PREFERRED EMBODIMENT 
The novel jack attachment 10 is shown in the drawings mounted on a motor 
vehicle transmission jack 12. 
The transmission jack 12 is of the common type having a lift arm 14 adapted 
to raise and lower transmission parts at its forward end. A typical 
example of such a jack 12 is Hein Warner model 54. 
The attachment 10 may be secured to the jack 12 by any convenient means; in 
the drawings the attachment 10 is shown as being secured to jack 12 by 
bolts 16. 
The attachment 10 includes a base member 18 and a forward support member 
20. The support member 20 is shown as including a pair of forwardly and 
upwardly extending elongated members 22 and 22' rigidly secured to base 
member 18 and further including a cross member 24 rigidly secured to the 
elongated members 22 and 22' intermediate their ends. 
As best illustrated in FIG. 2, the jack attachment 10 is adapted to support 
a fully assembled 4-wheel drive transmission 26, including the transfer 
case 27 and the motor vehicle transmission support bracket 28. The forward 
portion of the elongated members 22 and 22' are adapted to supportably 
engage the forward casing of the transmission 26 and the base member 18 is 
adapted to supportably engage the transmission support bracket 28. 
The attachment 10 also is shown as including a means for positioning the 
transmission 26 relative to the attachment 10 and the jack arm 14. It is 
generally desirable that the transmission 26 be positioned on the 
attachment 10 so that the support bracket 28 is substantially vertical of 
the forward portion of jack arm 14. This assures good balance of the 
assembly. 
In the drawings the positioning means is shown as a pair of upright guide 
pegs 30 welded to the rear portion of base member 18 and adapted to be 
received through guide holes in bracket 28. With respect to model 350 and 
400 turbo-hydromatic transmissions used in 1973 through 1978 Chevrolet and 
GMC three-quarter ton and half ton trucks, it is generally not required 
that the guide holes be drilled in bracket 28 in that such bracket as 
manufactured generally have such guide holes. Such guide holes are 
centered with respect to the transmission and are spaced apart 
approximately 15 inches. If the guide pegs 30 are sufficiently long, e.g., 
one and one-half inches, the forward end of the transmission 26 may be 
tipped rearwardly and upwardly about an axis through the support bracket 
28 without danger of the transmission 26 dropping from the attachment 10; 
this is often desirable during repairs of the transmission 26. 
It is desirable that the attachment 10 be adapted to hold the transmission 
26 in a substantially horizontal position which is approximately the same 
position transmission 26 is mounted in the motor vehicle. It is further 
desirable that the elongated members 22 and 22' have such lengths, extend 
at such an angle and be so spaced apart that they engage the casing so 
that they do not interfere with the removal of the transmission 26 from 
the motor vehicle. 
The attachment 10 is also shown as including a drive shaft support member 
32 which keeps the forward drive shaft conveniently secured during 
removal, installation and repair. 
For model 350 and 400 turbo-hydromatic transmissions found in 1973 through 
1978 Chevrolet and GMC half-ton and three-quarter ton 4-wheel drive 
trucks, an attachment 10 having the following dimensions has been found to 
be particularly suitable: 
"A"--91/4 inches; 
"B"--121/4 inches; 
"C"--18 inches; 
"D"--143/4 inches. 
Utilizing the above dimensions and one and one-half inch angle iron to form 
elongated members 22 and 22', a suitable angle between the base member 18 
and the elongated members 22 and 22' is 143 degrees. 
The method for removing a fully assembled 4-wheel drive transmission 26 
from a motor vehicle includes positioning jack 12 mounted with attachment 
10 under the transmission unit and activating the jack arm 14 to 
supportably engage the motor vehicle transmission support bracket 28 and 
the forward portion of the casing of transmission 26. Since the attachment 
10 is adapted to support the transmission 26 in substantially the same 
position as it is mounted in the motor vehicle, the base 18 and the 
elongated members 22 and 22' will engage the transmission 26 approximately 
simultaneously. 
In the event the positioning means utilized is guide pegs 30, it may be 
required to drill guide holes in the bracket 28 in some models prior to 
positioning and activating the arm 14. 
After the jack 12 has been positioned the transmission 26 may be 
disconnected from the drive train of the vehicle and the motor vehicle 
transmission support bracket may be disconnected from the vehicle as well. 
When the transmission 26 is fully disconnected from the motor vehicle, the 
jack arm 14 is activated to lower the transmission 26; it may then be 
moved to a convenient work area where the transmission may be repaired. 
Installation may be accomplished by following substantially the same 
procedure in reverse. 
Other embodiments of the invention will, of course, be apparent to those 
skilled in the art.