battery or alternator

I'm in sort of the same boat Old is in. 856 diesel. Batteries were dead from sitting. Jump, it runs fine no gauge, light not blinking or on, so assume alternator is good. Couple days later I have to drag it to start. Yes it will drag to start. So finished what I needed it for, now I would like to fix it. Took alternator in and had it tested, says it is not good. I question the ability of the place and came home with it to keep the belt tight while using. It has the 3EH batteries in it and both batteries when charged are not reading with meter the next day after removing charger. Posts look warped on the positive posts to both batteries and sides look a bit swelled. I'm figuring battery time. Tractor was charging when it was run fairly regularly. This has the old square regulator for charging and one of the reasons for the doubt in the test of alternator at auto parts store. Would like to solve this though don't want to just throw parts at it. I'm going to probably rob a battery out of something else to start this week. Then I guess see what happens then.

(quoted from post at 09:21:26 10/21/21) I'm in sort of the same boat Old is in. 856 diesel. Batteries were dead from sitting. Jump, it runs fine no gauge, light not blinking or on, so assume alternator is good. Couple days later I have to drag it to start. Yes it will drag to start. So finished what I needed it for, now I would like to fix it. Took alternator in and had it tested, says it is not good. I question the ability of the place and came home with it to keep the belt tight while using. It has the 3EH batteries in it and both batteries when charged are not reading with meter the next day after removing charger. Posts look warped on the positive posts to both batteries and sides look a bit swelled. I'm figuring battery time. Tractor was charging when it was run fairly regularly. This has the old square regulator for charging and one of the reasons for the doubt in the test of alternator at auto parts store. Would like to solve this though don't want to just throw parts at it. I'm going to probably rob a battery out of something else to start this week. Then I guess see what happens then.

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With the tractor running full field the alternator (bypassing the regulator) and see if it charges.

How do you full field the alternator on the old Pre 10si models? This is from the 60's model with the old square regulator with the 4 wire plug on it.

(quoted from post at 09:47:24 10/21/21) How do you full field the alternator on the old Pre 10si models? This is from the 60's model with the old square regulator with the 4 wire plug on it.

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Jumper wire from a battery power source to the alternator field terminal. You can do it at the alternator or the regulator plug.

I believed that an 856 could not be started by pulling (dragging). Does it not have the TA? I'm a little bit puzzled?!

Your battery are toast.You may have charging issues,but the batterys are done.Charge the battery and check with a load tester.If they fail(they will),replace them.Both as a pair.

Im bettimg it's factory'TA Delete'.Or has a'TA Eliminator' kit installed.

To full field test it, at the regulator, unplug the harness, put a jumper from F to 3.

With the engine revved up, it should go to full charge. Just test it, don't leave it for more than a few seconds.

If the alternator proves to be bad, now would be a good time to upgrade to an internal regulator alternator. Probably be cheaper and easier to find. Requires a harness plug and minor wiring mods, easy!

Hope your problem doesn't turn out as odd as mine seems to be. I just jumped the VAC and took it to the shop. Volt reading across the battery when running was around 8-10 volts not running 5-6 volts across the battery. Seem odd unless the battery is so bad it pull that much voltage from the alternator

Give Berry a call at Elliot's Starter and Alt. shop in down town Oak Grove MI.Google their web site. Berry worked with
Bill for years and took over after Bill Elliot passed, they used to be just north of Howell at a house Bill owned. They can fix about anything to do with starters, gen, alt, or voltage reg.And their prices are good. Phone 517-546-2199.

Thanks Guys. I'm going to swap out a battery out of another tractor to start with then I can do the full field check on the Alternator. If it passes then will look at the regulator for problems. If it fails I will be going with the 3 wire conversion of the internal regulated model. That would put me with the same set ups as a few of the other tractors around here. For the battery I just put the Group 31's with the stud tops in again for standardization. I just put a plate over the old battery tray with an edge around it then set the battery in and hook up with new cables. Solves a lot of connection problems. I have not replaced a set of those long skinny 3EH's in 30 years. As for the TA deal. I could not tell you if it is delete or not the lever has been froze since I hauled it home for my brother before I bought it from him. I just know I can drag start it and my 806 and dad's 1466 and those I do know are TA deletes. I know the 806 should have a TA and the 1466 used to have one. When I went through the complete transmission for dad I deleted it then since it would slip pulling it on the chisel plow and never used them anyway. So don't miss them. Now I'm getting off track.