So how to make an upside-down axle work?: Grassroots Motorsports forum: Grassroots Motorsports Magazine

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Dec. 13, 2011 3:27 p.m. oldopelguy Dork

My forklift has a 3' wide Dana 60 axle on the front of it and steers from the back. I am looking to re-power it and instead of using the original trans and transfer case and adapting it to the new motor it seems like it would make more sense to flip the engine around and dump the transfer case all together. Unfortunately that would have the driveshaft turning the wrong direction.

Is there some combination of high pinion or reverse cut ring and pinion that could be mounted in a regular housing and run backwards? Or how do I make an axle survive upside down? It'll be slow speed, so even grease might be an option?

Or, similar tack, is there one of the GM 60 degree bolt pattern FWD tranny's that has a spool available or is easy to lincoln lock? Running the axle shaft from one side to my current axle would be easy enough, turn the right direction, and be the right speed.
Dec. 13, 2011 3:38 p.m. Strizzo SuperDork

flip the axle over.
Dec. 13, 2011 3:47 p.m. familytruckster Reader

Front axle gears from a 4x4?
Dec. 13, 2011 4:23 p.m. Tom Heath Web Manager

Many 4x4s use the same ring and pinion set for the front and rear axles. The fronts push "backward" on the hypoid teeth, which is a big part of the reason trucks (ahem...JEEPS) are noisy. (NVH noisy, not necessarily exhaust.)

Some GM trucks (I'm sure there are others) use a reverse cut ring and pinion on the front axle; I know the later model Tahoe/Suburban/Hummers did. You're kinda stuck with a specific ring gear diameter that way though, so I'm not sure that will help at all. Also, I think the latest batch of Heavy Duty Dodge Rams have reverse cut ring/pinion sets on the front axle, and the pumpkin from those trucks is the same casting as K-5 era Chevy Blazers with different axle tubes and brackets.

And I thought my time in the axle factory was wasted...hope that helped a little.
Dec. 13, 2011 5:36 p.m. oldopelguy Dork

The problem with just flipping an axle is that the vent is on the bottom and the oil level would have to be wonky to get oil to the pinion bearing. I suspect a guy could pack those bearings with grease, and all the bearings for that matter, but would it work on the gears?

Front axles usually turn the wrong direction to use to what I need. Usually the front and rear driveshafts are connected with a chain or the like, which effectively reverses the direction of the driveshaft going into the axle. If you flip the engine,trans, and transfer case around in a 4WD truck, so the engine fan is towards the rear of the truck, the truck would have 5grars in reverse and one forward; the forward gears would go the direction the engine fan is. I need the back of the engine to be the front.

Some of the truck front axles use a housing that is a modified version (of say the Dana 44) set up for the pinion to be higher than axle centerline. Can those gears be installed in a regular low pinion axle to flip the direction?
Dec. 13, 2011 6:13 p.m. HappyAndy HalfDork

Forklifts are my business, what you are describing sounds odd. What kind of forklift is it?
Dec. 13, 2011 6:36 p.m. HappyAndy HalfDork

To be more specific, I've never seen a forklift with the "front" of the engine facing the drive axel. Everything relatively modern has the "front" of the engine towards the counterweight. I sounds like you are working on something really old, and probably very big.

BE AWARE THAT BY MAKING MAJOR CHANGES TO THE DRIVE TRAIN YOU WILL BE ADVERSELY ALTERING THE MACHINES CENTER OF GRAVITY! CAUSING THE WEIGHT THAT IT CAN SAFELY HANDLE TO BE DECREASED BY AN UNKNOWN AMOUNT!
Dec. 13, 2011 6:38 p.m. oldopelguy Dork

It's called a Big Dipper, made in ND I think by a company called Mobility which has been absorbed by someone else. It uses a Ford industrial engine and is FWD. I have two of them, one works but I'd like to convert the parts one to some more modern drivetrain.

Most of the units were set up with buckets and used like skid-loaders, but one of mine has a mast instead. Moving the engine rearwards in the chassis can't reduce the capacity nearly as much as the 300 lbs of weights I will be taking off to make the whole unit smaller. I'm looking to downsize the machine to something more yard friendly and less industrial. I want a smaller unit for hauling 800lb engines across the grass instead of 4k lb cars. For big loads I will still have the other unit.
Dec. 13, 2011 7:03 p.m. HappyAndy HalfDork

In reply to oldopelguy: I'm for DIY engineering as much as everyone else in this community, but as a professional technician in the lift truck industry, I think you are heading for trouble with this plan.

Just my .02¢ , but a hard earned and well informed .02¢
Dec. 13, 2011 7:33 p.m. T.J. SuperDork

In reply to HappyAndy:

2 hundredths of a cent isn't a whole lot of an opinion......a normal opinion is about 100 times that.
Dec. 13, 2011 11:19 p.m. curtis73 Dork

Dana 60s have ring and pinions made both ways. They're used a lot in Airplane tugs, forklifts, etc.

What you're looking for is a ring/pinion tooth slant that wants to push the ring gear and pinion away from each other when operating in the primary direction. That is to say for instance in a car, when operating in forward, the torque of the pinion should be trying to push the ring gear out the cover. So in a D60 (or any axle) in a RWD application, where the two mesh, the teeth would be pointing down toward the front of the car.

front 4x4 axles use the same ring and pinion, they just put the ring gear on the opposite side of the pinion. The tooth angle still wants to push the ring gear out the front of the cover, but the pinion meets it on its upward arc instead of its downward arc like in a rear axle.

I've seen both tooth angles in a forklift (not necessarily in a D60) because they spend pretty much equal time going forward and backward. Their goal is not long-term torque application in one direction like a vehicle.
Dec. 13, 2011 11:33 p.m. curtis73 Dork

I like the grease idea, but would require frequent greasing. You could plug the vent hole and drill a new on on top.

But... help me understand a little better. I'm assuming rear engine, mid tranny, then front axle. Longitudinal engine? I guess what I'm asking is, I assume its set up exactly like most RWD cars, its just that you face backwards, right?

If so, what direction does the engine turn when you look at the crank snout? And what direction does the driveshaft turn when you are moving forward (toward the forks?).

Basically I need to know which direction everything is turning. The Hyster we had at the shop was exactly like a car; engine pulleys turned clockwise, driveshaft clockwise, tranny clockwise. The only difference was that the labels for F and R were swapped. When you moved the forklift forward (toward the forks) the tranny was effectively in "reverse," meaning it was turning the driveshaft opposite the engine.
Dec. 14, 2011 9:17 a.m. iceracer SuperDork

I worked on fork lift for several years. All of them had a torque convertor and a planetary transmission for forward and reverse. and drove straight to the pinion. Engine turned in the normal direction..
Dec. 14, 2011 9:25 a.m. oldopelguy Dork

Currently it is set up just like the front half of a 4x4 truck, with the fan end of the engine up towards the forks. Engine, trans, then oddball transfer case with only a front output, and it directly under the center of the engine. The front axle has no steering, it steers with the non-driven rear axle. Engine turns normally, CW from the fan end, then a chain drops it to the driveshaft, which looking at the pinion on the rear of the front axle turns CCW to go in the forward direction

I would mostly like to replace the engine, but it s a weird Ford industrial one that seems to only share bolt patterns with tractors. That means weird adapters to hook something else up to an equally oddball transmission and transfer case. If I can figure out how to make the axle work in the opposite direction I can flip the engine and trans end-for end and have the fan end of the engine in the rear and drive the axle directly off the end of the trans.

My other thought was to use a FWD transverse transmission, mounted to the new engine and installed longitudinally and use one of the wheel speed axle shafts to drive the existing axle. This would also give me some more gear reduction and keep the speeds down, but it requires splitting some FWD trans case and welding up a diff, which I have never done before. I am also not sure the frame is wide enough for that combination, since the axle needs to be pretty centered and that would push the engine off to one side typically.

The things really are more of a home-brew tractor than forklift, it just so happens that one of them has a mast on it. They were used primarily in fertiliser plants with wide buckets to move bulk product around indoors in tight quarters. I would just like to take one of them a little further towards car/truck stuff and further from tractor, since modern fuel management and ignition systems are non-existent for tractor stuff as all the new ones are diesels. Doing the manual choke throttle lever control dance on something that gets started and driven only long enough to cross the yard seems silly to me.
Dec. 14, 2011 10:11 a.m. RossD SuperDork

Are you sure there isn't an adapter at the rear of the engine to get to that odd ball bolt pattern? I was under the assumption that Ford's industrial engines were typical Ford automoble blocks but with just slightly different stuff bolted on.
Dec. 14, 2011 12:07 p.m. jstand New Reader

I guess what I'm wondering if you are just looking at low speed operation, why worry about swappIng out the diff.

Just do like Curtis mentioned and swap the labels for R and D if it runs an auto tranny. Swap in whatever engine and tranny will fit in the space available and label the gear shift as required.

If you are goin to use a manual tranny you could look for an engine that has counter rotating marine version and spin the engine backwards.