Johnson bar

Always believed the term Johnson Bar referred to the reverse lever on a steam locomotive in the US.

Depends on what you mean by "special transmission).....on late units the tractor will move forward in third and fourth (one combo) or third and fifth (another combo)....with the forward/reverse lever in either forward or neutral positions.

The term "Johnson Bar" seems to have many applications of which the "forward/reverse" lever on Caterpillars is a correct one.

This 2U must have been ordered w/ this special tranny for use as push cat- in 1 or 2 or 4th gear the neat shuttle lever will move you forward -neutral in center & backwards { in every gear reverse is faster} except for 3rd- in which case the lever has no control of anything- compared to my other 2U there is 1 gear option missing to get the fast reverse- this machine will go 5 in forward and 7 in reverse- 3rd is aprox 3mph forward only option- I was worried that something wouldn't get lube is shuttle lever was in wrong position all day long {ie- like RD7 will give tranny oil problems if run in reverse to long}--😞 was no problem today as ground was loose enough that I ran in 2nd as reverse was required when blades decided to stall.- if this condition isn't noticed quickly the 30 ft dbl offset becomes a huge dump rake..

There is a 8F8501 Transmission Group - High Reverse for 2U15001-2U21512 (one of many options) that shows speeds of 2.2 mph 1st, 3.1mph 2nd and 6.9mph 3rd in reverse and only four gears forward.
What is your serial number?

There is a 8F8501 Transmission Group - High Reverse for 2U15001-2U21512 (one of many options) that shows speeds of 2.2 mph 1st, 3.1mph 2nd and 6.9mph 3rd in reverse and only four gears forward.
What is your serial number?

[quote="Old Magnet"]There is a 8F8501 Transmission Group - High Reverse for 2U15001-2U21512 (one of many options) that shows speeds of 2.2 mph 1st, 3.1mph 2nd and 6.9mph 3rd in reverse and only four gears forward.
What is your serial number?[/quote]
Just put her away for night-serial plate is hard to read but it looks like 2U21434SP- and it does have the 8F8501 option- along w/ much bigger air cleaner & for some reason the hood has been extended & hard nose redrilled & moved forward & spacer to move fan ahead{found all these goodies when I sandblasted to paint} also had nice enameled plates on side of hard nose that said Hi output D-8- I was wondering if there is a proper setting for the forward/reverse lever[old timer around here call it Johnson bar??] when in 3rd gear-- maybe it doesn't matter since it doesn't do anything? but would hate to ruin something for not knowing..I am pretty proud of this old cat & would like to keep it in top notch shape-I could share pics if I knew how..

Hi, Tanker.
The thought did occur to me when I saw your first posts about your D8 that it might have been modified for scraper pushing. I didn't know that some of these jiggers were fitted with a 6.9 mph reverse gear. I suspect that if you had posted photos of the beast, you would have been inundated with information about it 'cos the Hi-Output D8's seem to spark a LOT of interest on these boards.

So, WHERE are the photos? LOL. Lookee here for 'destructions' on posting photos.

http://www.acmocbb.org/ACMOC_BB/showthread.php?t=288

You can see one man's Hi-Output D8 restoration story here - carefull, this is an opposition site and you become infected.

http://www.antiquecaterpillar.net/ACF_v2/showthread.php?t=10118

Make yourself a sandwich and a coffee before you settle down to read it. It's now 90 pages long.