1966 856 transmission lower fill hole size question

[FLtractor 8]

Afternoon, 

wondering what size bolt this is for the lower transmission fill hole.. and what size extension would I need to fit this as pictured here? (What size wrench too) Orginal post stated that extension is factory but have yet to hear back from poster as thread is at least a decade old. Is there a name for such. 

[Achto 28,610]

  On 4/4/2025 at 6:40 PM, FLtractor said:

wondering what size bolt this is for the lower transmission fill hole

 

 Not a bolt at all. It's 3 pieces.

 

1 - 1" long 3/8" pipe nipple

1 - 3/8" pipe coupling.

1 - 3/8" pipe plug

 

All pieces should be readily available at any hardware store. 

I believe pipe plug takes a 9/16" wrench. 

 

Edited Friday at 07:14 PM by Achto

[FLtractor 8]

  On 4/4/2025 at 7:12 PM, Achto said:

 

 Not a bolt at all. It's 3 pieces.

 

1 - 1" long 3/8" pipe nipple

1 - 3/8" pipe coupling.

1 - 3/8" pipe plug

 

All pieces should be readily available at any hardware store. 

I believe pipe plug takes a 9/16" wrench. 

 

Poor wording on my part. Thank you. The orignal poster stated that if you fill the transmission full till it reaches the end of that extension hole.. then that is full enough oil for a well oiled transmission. If I did fill the transmission this way with the extension, would I need to tip the tractor anyway to fully fill the transmission? 

Edited Friday at 07:20 PM by FLtractor

[Achto 28,610]

  On 4/4/2025 at 7:19 PM, FLtractor said:

The orignal poster stated that if you fill the transmission full till it reaches the end of that extension hole.. then that is full enough oil for a well oiled transmission. 

 

True. Usually only the 6 & 8 speed trannys had the extension. On the 3 speed tranny the pipe plug went directly into the tranny with out the extensions, like in the pic below.

Edited Friday at 07:29 PM by Achto

[FLtractor 8]

  On 4/4/2025 at 7:22 PM, Achto said:

 

True. Usually only the 6 & 8 speed trannys had the extension. On the 3 speed tranny the pipe plug went directly into the tranny with out the extensions, like in the pic below.

So would the extension be of any real benefit to my 3 speed filling? 

[Achto 28,610]

  On 4/4/2025 at 7:44 PM, FLtractor said:

So would the extension be of any real benefit to my 3 speed filling? 

 

You would gain oil capacity that might be of benefit. Not sure it is necessary though. 

[FLtractor 8]

  On 4/4/2025 at 7:49 PM, Achto said:

 

You would gain oil capacity that might be of benefit. Not sure it is necessary though. 

Makes sense. I Would much rather fill the transmission thru that hole than having to remove the shifter. 

[SylvanLakeWH 27,241]

  On 4/4/2025 at 7:49 PM, Achto said:

 

You would gain oil capacity that might be of benefit. Not sure it is necessary though. 

I just filled one with 1/2 quart extra by tipping tractor up on left side, fill, put in plug and lower it... easy peasy... that trick brought to you by @Pullstart...

[FLtractor 8]

  On 4/4/2025 at 8:30 PM, SylvanLakeWH said:

I just filled one with 1/2 quart extra by tipping tractor up on left side, fill, put in plug and lower it... easy peasy... that trick brought to you by @Pullstart...

Ahh that’s where I’ve heard the tipping tractor to side before. Thanks 

[Racinbob 11,667]

I haven't bothered with that 'fill' hole for decades. Figure 1.5 quarts for the 3 and 4 speeds and 2 quarts for the 6 and 8 speeds and be done with it. The only thing that extension did was eliminate the need to tip the tractor to get the proper amount in if you insist on going that route. I think it was only factory installed on the 6 speeds making folks think they required more. Not so. In reality it would be fine to run 2 quarts in all of the Unidrive manuals.

 

[FLtractor 8]

  On 4/5/2025 at 9:14 AM, Racinbob said:

I haven't bothered with that 'fill' hole for decades. Figure 1.5 quarts for the 3 and 4 speeds and 2 quarts for the 6 and 8 speeds and be done with it. The only thing that extension did was eliminate the need to tip the tractor to get the proper amount in if you insist on going that route. I think it was only factory installed on the 6 speeds making folks think they required more. Not so. In reality it would be fine to run 2 quarts in all of the Unidrive manuals.

 

I was looking at this engine and gear oil amount for the 856. 

[Racinbob 11,667]

That highlighted 1075 was on that sheet when I saved it. Didn't mean to mislead you. 

[FLtractor 8]

  On 4/6/2025 at 2:06 AM, Racinbob said:

That highlighted 1075 was on that sheet when I saved it. Didn't mean to mislead you. 

Ahh ok. Thank you.

what kind of wrench is needed for the transmission drain hole on the bottom? Appears to be 6 sided. Not familiar with a socket or a Allen that is 6

[pfrederi 18,289]

1/4" allen wrench socket

Edited Sunday at 02:28 PM by pfrederi

[FLtractor 8]

  On 4/6/2025 at 2:26 PM, pfrederi said:

1/4" allen wrench socket

Thank you!! Also been attempting to use a pair of vice grips and channel locks to no progress whatsoever ever for over a hour to remove the engine oil drain plug threaded cap  here

Edited Sunday at 03:37 PM by FLtractor

[pfrederi 18,289]

Small Pipe Wrench or pliers like these

 

 

[FLtractor 8]

  On 4/6/2025 at 3:38 PM, pfrederi said:

Small Pipe Wrench or pliers like these

 

 

Been attempting to use those or a pair or vice grips but due to all the metal in the way I can’t seem to get any good grip with leverage.. I did remove a nut for the battery metal holding piece but the bolt doesn’t move and all the pressure that would be applied to the threaded end cap is applied to that bolt.. so that doesn’t help.. would be the prefect location to remove the threaded end cap.. maybe I should get a shorter smaller pair of channel locks. Seller did tell me he haven’t changed the oil in 4 years.. checked it thru dipstick hole.. oil level good and proper color.. just not having been removed in so long the threaded end cap doesn’t wanna come off 

Edited Sunday at 04:36 PM by FLtractor

[rjg854 11,865]

Does unhooking the brake/clutch pedal gain you any extra room to get at the cap?  Work from the other side?

Edited Sunday at 04:58 PM by rjg854
Add

[Pullstart 64,387]

Sometimes on pipe fittings, you’ll find that if you can’t loosen it, you can still tighten it.  It’s the weirdest thing.  Try opening up those slip groove pliers one more notch, and getting the jaws in there good.  Give it a hit to the right and I bet five bucks it’ll move.  Prizes redeemable in high fives, or worthless chatter at the Big Show!  

[FLtractor 8]

  On 4/6/2025 at 4:57 PM, rjg854 said:

Does unhooking the brake/clutch pedal gain you any extra room to get at the cap?  Work from the other side?

Attempted that.. no luck. Either unhooking cable or From other side. 

[FLtractor 8]

  On 4/6/2025 at 6:23 PM, Pullstart said:

Sometimes on pipe fittings, you’ll find that if you can’t loosen it, you can still tighten it.  It’s the weirdest thing.  Try opening up those slip groove pliers one more notch, and getting the jaws in there good.  Give it a hit to the right and I bet five bucks it’ll move.  Prizes redeemable in high fives, or worthless chatter at the Big Show!  

Will give that a go eventually.. took break for now. Under that threaded cap is there anything preventing oil from leaking out once it’s removed such as a nut? 
is there any simple recommended replacement such as a fitting or value for that dreaded threaded end cap once it’s off so don’t have to go through this everytime ? 

[Pullstart 64,387]

  On 4/6/2025 at 7:02 PM, FLtractor said:

Will give that a go eventually.. took break for now. Under that threaded cap is there anything preventing oil from leaking out once it’s removed such as a nut? 
is there any simple recommended replacement such as a fitting or value for that dreaded threaded end cap once it’s off so don’t have to go through this everytime ? 

You could opt for a 1/2” npt plug right into the block, opposed to a chute to get it outside the frame rail.  It might be a challenge to get to, but less potential leak points.

[Pullstart 64,387]

Putt Putt has no drain tube, as pointed out in this video:

 

 

[FLtractor 8]

Would someone have a link to which: 

-engine oil 

-transmission filters

-air filter

I need for my 1966 856… would like to replace all once I finally get the threaded cap off and then get to the transmission drain plug as well. 

[Blasterdad 3,005]

  On 4/7/2025 at 11:56 AM, FLtractor said:

Would someone have a link to which: 

-engine oil 

-transmission filters

-air filter

I need for my 1966 856… would like to replace all once I finally get the threaded cap off and then get to the transmission drain plug as well.