Fast reverse, Case VAC

D Stobert · Apr 9, 2009

I have a 1945 Case VAC I got from someone in a trade. I was wondering if there is anyone knowledgable in the transmissions on these things? It backs up so fast you can hardly control the steering to keep up with it, and that's only on loads light enough for it to get moving. I can't imagine any designer being in such a hurry to go backwards on anything, much less a farm tractor. One hypothisis I have: Is it possible on this machine that the tranny was taken apart, and the gears got switched between the main shaft and countershaft? Thanks for any insight. Dan

Anonymous-0 · Apr 9, 2009

Mine is the exact same way. I throttle it down to nothing before I go in reverse. Luckily that little thing has power at low idle.

Anonymous-0 · Apr 9, 2009

You've got the french army version......... :shock: :roll:

Dave

Bob · Apr 9, 2009

It's PROBABLY not engineered that way, just done that way to save money.

MANY truck and tractor manual transmissions have a fast reverse. They often use the upper and lower gears used for another forward speed and sick a countershaft gear between them to reverse the direction.

Doing this saves $$$ for the manufacturer.

To get a slower reverse, you have to use a countergear (compound gear) with a wide ratio and this means a large "lump" on the side of the tranny case to house the large gears.

It could also be done with additional countershaft, but, offhand I can't think of a real-world example of that.

big jt · Apr 9, 2009

I have no knowledge of the VAC reverse. However, we have a 1939 John Deere B (purchased new) that has a rediculously fast reverse. The designing engineer did not use his good judgement.

JDemaris · Apr 9, 2009

Many older single range tractors are like that and some worse , especialy some older Fords.
VAC with the 10-28" tires goes 3.2 MPH backwards. Some Fords goe 4 - 6 MPH.

VAC at full throttle goes 3.2 MPH in reverse @ 1425 RPM.

VAH goes 3.7 MPH reverse @ 1425 RPM

Ford 601 with 4SP full throttle 4 MPH at 2000 RPM
and 3.45 MPH @ 1750 RPM.

IH B[-275 low range is 2.3 MPH in reverse @ 1875 RPM. High range it's 6.1 MPH.

Ford 8N 4 speed - 4.19 MPH @ 1500 RPM, 5.58 MPH @ 2000 RPM.

RobMD · Apr 9, 2009

most tractors have reverses oriented somewhere between the speeds of 2nd gear and sometimes 3rd.

As Bob said, a simple counter-idler is found in most tractors - except for John Deere horizontal 2 cylinders. In the putt putts, often the same gear that drives the second gear is slid right over onto the differential gear, making a reverse right onto the differential.

John Deere got away without putting money into a reverse - it basically already existed.

In most vertical engine vehicles, even cars and trucks, the reverse gear is basically another idler to counter the forward speeds.

A direction reverser works in the same way - another gear added into the train.

D Stobert · Apr 9, 2009

Thanks, Guys. I guess that's just the way it is. When I was a kid, my folks had a real tractor, Ford 8-N with hi low range. Boy I miss that tractor! Dan

Ill John · Apr 9, 2009

You could buy a Minnie, they have a slow reverse

Fast reverse, Case VAC

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