Engineers sprag is slipping

Hello, I am far from a tractor mechanic. I am pretty good at doing some heavy hydraulic maintenance on level D full flight simulators motion systems and control loading control system but tractors are a mystery to me.

How this ampli-torc works is a mystery to me, maybe once I have it out and can see it moving etc and play with it, it will be clearer but in mean time....

An animated youtube video would be great for MM amplitorcs but I have never found one.

Half century ago I grew up on a small Ohio farm and my Dad owned a new Super Jet 3.

Well now I live on a corner of the old farm and disabled. I bought a U302 to get around land and area with. Problem is low torc is slipping.

Reverse almost ever time (I don't know why rev would matter and maybe consequence). Others gears its a 50/50 shot if it grabs or not.

If it slips and I cycle clutch slow, most times it takes.

I dont let it sit and slip. I bought it this way and dont know what may have happened in past.

I can get by but want to fix one day. What is a man looking at to fix this? Split tractor?

This engine is VERY good. I bet it dont roll over 2 cycles and it takes off every time. VERY strong.

Nice looking U302 with good rubber. It is worth fixing torc.

Any advice for a layman would be great!!!

Thank you.
 
First, Do you let the tractor warm up before you engage the low range? It also needs to run a few minutes in order to fill the a/t cavity at
the front of the transmission so nothing in there is running dry when you shift it. In high range it all spins together except for the sprag
clutch.

Those came with 90 wt. oil in the gearbox and it needs to be warm before it works reliably.

I have a 335 that I thought had a bad low range. But one day bush-hogging (in grass as tall as the hood) I needed to go slower, by that time
it was warm and it latched right in and worked fine the rest of the day.

An operator manual can probably be found available on Ebay. That should explain how the Amplitorque works.
 
If I did it right clicking on the link will take you to the U302 parts book.

If yours is serial number 1300 or before go to the ampli-torq group 1 or else go
to group 2.
U302 parts book
 
The clutch has a bunch of rollers and if the rollers do not all lock up at the same time the one that does lock up may break. I got rid of the heavy lub and put in 40 wt. transhydraulic lube and have had no problem
 

I wish it were warm up, I really do. Full operating temp on a hot day and it still does it. Especially when using reverse, not sure why that would make a difference.
 

No it does not. It seems like perhaps you were logged in and then made link. If so I would need be logged in also.

I have a G1000 Vista shop and repair manual I forgot about. It has a great exploded diagram I been looking at.

Need to have diagram and clutch in hand at same time for stare and compare.

Thank you!
 

Here is something I dont understand. If you start in low range and it is not slipping it would seem things are locked and working.

Why would it be running in low and then start slipping?

Also one other question. Way MM with amplitorc works if your on a hill in high range and shove clutch in, it does not roll backwards.

With a failing amplitorc, is there a way that would not work?

In other words, you cannot count on if in forward gear and high range it may not hold tractor on hill when you shove clutch is in as normal.
 
From what you are saying it sounds like your sprage is worn but not completely shot. If when warm it will start out in low range and work fine, and also if in high range and shift to low it slips push in on the clutch and release slowly it grabs hold and works. Then it is working after a fashion. I have a couple of tractors I have used for years in this condition. The problem it is worn to a point that it won't grab and hold on the fly when you shift from high to low on the go. You can use it this way till it won't work at all without doing any damage.

MMDEL
 

Here is what i am saying/asking:

When we talk about amplitorc failures I mainly here people talk about low side not working.

It seems high side it a direct connect of motor to transmission?

It seems sprag is part of high side? Or used for both low and high?

Is there a time when torc fails that it no longer holds on a hill when clutch is shoved in?
 

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