1959 871 transmission pressure test and band adjustment

[Wibblewobble]

Hello. i own 1959 871-D I have just adjusted my bands and also done a pressure test on all 3 servos. I own the older 801 service manual. followed instructions from the 801 service manual. The internet has the Ford 2000/4000 shop manual. In the 2000/4000 shop manual, they show a chart with the pressures for each servo in every gear. (Photo included) Question 1: Will this pressure chart apply to my 871? The book seems to have very similar information, just newer wording. My pressure issue, I believe I am having, is that my servo 3 shows pressures in every gear but park. The tractor moves in all gears, but gears R2, R1,1,2,3,4,and 9 nine put a heavy load on the tractor. 4th gear: more load is applied to engine then first for example. I have drained the fluid and removed the side cover plates and top cover plate. R2,R1,1,2,3,4 are the most noticeable. When I depress the inching pedal, the tractor also stops in the gears mentioned. Feels like the brakes are applied when I depress the inching pedal in any of those gears. 5, 6, 7, and 8 gears seem to function great. smooth running engine load for gear. If the inching pedal is depressed, the tractor will coast. In 5th, 6th, 7th, 8th, and 9th gear. 9th will coast also but seems to have to work harder than I think it should. 10th moves, but I did not drive it in that gear much before concern set in, and I then drained fluid. Thank you in advance for any info you can provide. Also, I'm sorry if I'm not posting this in the proper place. New guy problems.

 

[pomester]

Hello. i own 1959 871-D I have just adjusted my bands and also done a pressure test on all 3 servos. I own the older 801 service manual. followed instructions from the 801 service manual. The internet has the Ford 2000/4000 shop manual. In the 2000/4000 shop manual, they show a chart with the pressures for each servo in every gear. (Photo included) Question 1: Will this pressure chart apply to my 871? The book seems to have very similar information, just newer wording. My pressure issue, I believe I am having, is that my servo 3 shows pressures in every gear but park. The tractor moves in all gears, but gears R2, R1,1,2,3,4,and 9 nine put a heavy load on the tractor. 4th gear: more load is applied to engine then first for example. I have drained the fluid and removed the side cover plates and top cover plate. R2,R1,1,2,3,4 are the most noticeable. When I depress the inching pedal, the tractor also stops in the gears mentioned. Feels like the brakes are applied when I depress the inching pedal in any of those gears. 5, 6, 7, and 8 gears seem to function great. smooth running engine load for gear. If the inching pedal is depressed, the tractor will coast. In 5th, 6th, 7th, 8th, and 9th gear. 9th will coast also but seems to have to work harder than I think it should. 10th moves, but I did not drive it in that gear much before concern set in, and I then drained fluid. Thank you in advance for any info you can provide. Also, I'm sorry if I'm not posting this in the proper place. New guy problems.

Welcome to the board. You're in the right place.

Symptoms point to the valve body and a stuck valve. You'll need to pull the cover - follow the shop manual instructions carefully so as not to mangle any cables. The valve body is right on top and you'll be able to observe the action of the valves as you turn the control shaft. If necessary it's not difficult to remove the valve body and service it on the bench. Here's some pictures. https://forums.yesterdaystractors.com/threads/a-fresh-one-881.1778921/

Be sure to adhere to cleanliness when working on any SOS pieces.

 

[Wibblewobble]

Hello. Thank you for the reply. Just got home and was testing the movement of the valves. Servo 2 and servo 3 (two left-side valves) are hard to move and don't return back to their home position, like the clutch valves and servo 1 valve do in the control valve. Thank you! Truly believe that is the main problem. The fluid was black with some very fine clutch or band material in it. Bands needed a few turns for adjustment. Going to flush and wash down the inside of the trans with diesel fuel to get the insides as clean as I can. Will be removing the valve body. I am sure I will have more questions.

Wonderful thread that you posted! You seemed to have had almost the same valve body problem. So nice to get some answers. Thank you again. Great idea to leave the cover off and retest and adjust everything.

Thanks again
Doug

 

[pomester]

Hello. Thank you for the reply. Just got home and was testing the movement of the valves. Servo 2 and servo 3 (two left-side valves) are hard to move and don't return back to their home position, like the clutch valves and servo 1 valve do in the control valve. Thank you! Truly believe that is the main problem. The fluid was black with some very fine clutch or band material in it. Bands needed a few turns for adjustment. Going to flush and wash down the inside of the trans with diesel fuel to get the insides as clean as I can. Will be removing the valve body. I am sure I will have more questions.

Wonderful thread that you posted! You seemed to have had almost the same valve body problem. So nice to get some answers. Thank you again. Great idea to leave the cover off and retest and adjust everything.

Thanks again
Doug

With the description of the fluid it's probably a good idea to change the filter. I believe our host here has them, along with other suppliers.
David

 

[Tony Jacobs]

Hello. Thank you for the reply. Just got home and was testing the movement of the valves. Servo 2 and servo 3 (two left-side valves) are hard to move and don't return back to their home position, like the clutch valves and servo 1 valve do in the control valve. Thank you! Truly believe that is the main problem. The fluid was black with some very fine clutch or band material in it. Bands needed a few turns for adjustment. Going to flush and wash down the inside of the trans with diesel fuel to get the insides as clean as I can. Will be removing the valve body. I am sure I will have more questions.

Wonderful thread that you posted! You seemed to have had almost the same valve body problem. So nice to get some answers. Thank you again. Great idea to leave the cover off and retest and adjust everything.

Thanks again
Doug

Hello Doug , First off if your 871-D is a 1959
(Since you didn’t post a serial number and since Diesels are generally not legible anymore ) you have the first year SOS transmission . The casting number is 312259 on the left hand side . The band adjustments and pressure charts are different than the later Direct Clutch transmissions which have casting numbers of CONN7006B and C3NN7006B so yes you have to follow the manual for which type of SOS you have . The only CORRECT transmission fluid is Valvoline VV813 that you can pickup at any Napa store it matches the original Ford M2C41 spec and nothing else does especially the off brand cheap junk oils like tractor supply . Cleaning it out with diesel fuel is fine , change the filter and fill it the Valvoline oil to the fill plug then add another half gallon of ATF to it . Automatic trans fluid has a lot of detergents in it to keep the trans clean and when heated to normal operating temp will help break down the varnish in the SOS . SOS transmissions will cavitate on a steep side slope because of the low factory oil level . In all SOS’s I have worked on for the last 40 plus years that’s how I run the oil level on my own personal SOS tractors I run them one Gallon over the full level because I drag logs on 45 degree side slopes all the time with them . Thanks Tony

 

[Tony Jacobs]

Hello. Thank you for the reply. Just got home and was testing the movement of the valves. Servo 2 and servo 3 (two left-side valves) are hard to move and don't return back to their home position, like the clutch valves and servo 1 valve do in the control valve. Thank you! Truly believe that is the main problem. The fluid was black with some very fine clutch or band material in it. Bands needed a few turns for adjustment. Going to flush and wash down the inside of the trans with diesel fuel to get the insides as clean as I can. Will be removing the valve body. I am sure I will have more questions.

Wonderful thread that you posted! You seemed to have had almost the same valve body problem. So nice to get some answers. Thank you again. Great idea to leave the cover off and retest and adjust everything.

Thanks again
Doug

I forgot to mention when you get them up to normal operating temp you could burn your thighs on the sides of the transmission if you were wearing shorts that is Normal as these transmissions do not have external coolers on them . It doesnt do any damage to the transmission all clutch plates and bands are metallic not conventional asbestos’s type material like in automotive applications because of the high heat conditions . Tony

 

[Bern]

Bands needed a few turns for adjustment.

If true, you have big problems inside.

 

[Wibblewobble]

thank you all for the info hopefully, i can get to it this weekend and get you a up date

 

[Wibblewobble]

Guys can you confirm that I removed the correct bolts to remove the control valve. I have removed my fair share of gasketed assembly's this one is on their! Calling uncle for now on removing that. attached photo.

Thank you all again

 

[pomester]

Guys can you confirm that I removed the correct bolts to remove the control valve. I have removed my fair share of gasketed assembly's this one is on their! Calling uncle for now on removing that. attached photo.

Thank you all again

Remove the last two and it'll fall off - I'm not certain without looking at the book which are valve body bolts and which hold the valve body to the transmission, but if it won't fall off you haven't removed the right bolts.

 

[Tony Jacobs]

Guys can you confirm that I removed the correct bolts to remove the control valve. I have removed my fair share of gasketed assembly's this one is on their! Calling uncle for now on removing that. attached photo.

Thank you all again

Yes those are the correct bolts that hold the two halves together . With the TR markings on the heads those are factory bolts so it hasn’t been apart before or if it was the mechanic was careful enough to reuse the correct bolts and in the correct holes . I usually have to use longer grade 8 bolts on the 3 filter tube holes because they are usually the wrong ones or partially stripped . Tony

 

[Wibblewobble]

I just got it off!
Spent about one hour gently prying all the areas of the body that I though would not brake anything. The bolts that are removed in the photo are correct. You leave the two in to hold the valve body together. manual does not show to good. Going to take it to work with me tomorrow and hopefully I get some time to clean and inspect the surfaces. That was the most stuck gasket that I can rember ever getting off. 65+ years mated together i would not wand to move also..lol. The valve for Servo 3 is stuck good. servo2 does not feel that great also. compared to the 3 clutch valves. clutch valves feel smooth and return nicely

Again Thank you so much for your replays.
Doug

 

[Wibblewobble]

Got some time in between prying on the control valve to clean the sump area. My plan at the moment after going through the control valve.
I going to flush out the trans as much as i can. going to borrow solvent wand from work this weekend and and just spray the insides out. Looks pretty clean for 65 years. i have seen far worse fines in automotive transmissions that are 10 year old or newer. But I never really worked on one of these sos's. i hope that not totally horrible the fines in the trans. band adjust was maybe 2 turns at the most. Hoping that not real bad. I did see band #1 after control valve removal. looks ok, looks like a normal band that I have seen in automotive. Going to borrow works bore scope to see if I can look around some at the other 2. I like Pomester idea of leaving the top cover off and running the tractor through its gears in towing/service mode and inspecting everything. Tony, I did pick up 5 gal of tractor supply fluid, befor i started thread. I got the VP racing brand fluid. Thank you for the fluid info! I going to use the VP fluid first, just to test everything. Will be used as a system flush for any remaining fines that might be in tubes or passage ways. Trying best to make insides clean as possible. Might throw in some ATF like you said with the VP stuff to clean out any thing still inside. Will drain after a few runs and replace with the fluid you recommended. I am ordering filter for trans also. might make that 2 of them if things go good and start with fresh filter and the fluid you recommended

Truly thank you all again
Doug

 

[Tony Jacobs]

Got some time in between prying on the control valve to clean the sump area. My plan at the moment after going through the control valve.
I going to flush out the trans as much as i can. going to borrow solvent wand from work this weekend and and just spray the insides out. Looks pretty clean for 65 years. i have seen far worse fines in automotive transmissions that are 10 year old or newer. But I never really worked on one of these sos's. i hope that not totally horrible the fines in the trans. band adjust was maybe 2 turns at the most. Hoping that not real bad. I did see band #1 after control valve removal. looks ok, looks like a normal band that I have seen in automotive. Going to borrow works bore scope to see if I can look around some at the other 2. I like Pomester idea of leaving the top cover off and running the tractor through its gears in towing/service mode and inspecting everything. Tony, I did pick up 5 gal of tractor supply fluid, befor i started thread. I got the VP racing brand fluid. Thank you for the fluid info! I going to use the VP fluid first, just to test everything. Will be used as a system flush for any remaining fines that might be in tubes or passage ways. Trying best to make insides clean as possible. Might throw in some ATF like you said with the VP stuff to clean out any thing still inside. Will drain after a few runs and replace with the fluid you recommended. I am ordering filter for trans also. might make that 2 of them if things go good and start with fresh filter and the fluid you recommended

Truly thank you all again
Doug

Don’t worry about the ATF during flushing it won’t be in there long enough to do anything . Add the ATF after you get it cleaned out and add the correct 813 oil and leave it in there . Depending on how hard you use it will take a while to break down the varnish . As I said earlier the harder and longer you use and the hotter it gets the ATF will do its thing and clean it up . When I start dragging logs and moving firewood I get them hot and thats what works the best . A lot of these old beasts have had junk oil in them for years and it’s a while to get them cleaned up . Tony

 

[Wibblewobble]

Got some time today to clean and inspect the valve body. happy to report that it cleaned up nice. I did not see anything bad looking in it. ordering gasket material and filter. On hold till then. Valves feel great now with clean holes and some fresh oil.

thank you all again
Doug