Some 8 Speed Transmission Hints

Not doing a full tutorial but I have one in the shop right now and I thought I would put some helpful pics + hints in here.

This one is a 310-8 that lost the right outer bearing and over time took the expensive inner bearing out with it. The outer bearing for a 1" axle shaft (part # 1528) has 36 needles in it and I've found them all so I didn't feel the need to remove the shift forks and gears which is the biggest part of a complete tear down. A good strong magnet is good for finding all these loose parts that may cause more damage in the future.

Hint #1- If you take everything off of the tractor minus the transmission itself and give it a good pressure washing or cleaning it will make for less mess and be less mess to deal with while working on it. Removing the brake and input shaft pulleys before clean up will also help to get the mess out from under them.
Hint #2 - It's easiest to remove all the pulleys and hitch and clean the shafts before the transmission is removed from the tractor if possible so the tractor can hold the transmission for you while doing this.
Hint #3 - When taking a case apart the small (right) side always goes down.
Hint #4 - If you have some steel laying around (or wish to find some) making a jig to hold the transmission while working on it makes things much easier. You can see the one we made here, nothing fancy, just made from an old piece of used angle iron that was laying in the back...

** If replacing a bearing on the large (left) side of the case then they will all be easy to access. If any bearing needles, balls, or pieces are missing it would be a good idea to pull the differential and axles, cluster, brake shaft assy, and reverse idler because it only takes a min. It is also a good idea to do just to check out the other bearings and do a better clean up inside. But there is 1 trick, see hints below.

Hint #5 - Axles and differential come out first.

** If you are working on the differential or axles shafts then that is all you need to do to work on them.

Hint #6 - Shift the 2nd and 3rd gear fork upward into the 2nd gear position. It will be the fork closest to the rear of the transmission. This will allow for easy removal of the cluster and brake shaft assy. The reverse idler is the wide gear at the bottom front off to itself. There is also a labeled pic below.
Hint #7 - After reassembly before the case is put back together remember to shift the 2nd and 3rd gear fork back to neutral.
Hint #8 - This would be a good time to replace all of the seals, needed or not, since everything is cleaned up and apart already.

That is as far as this one is going to be disassembled to do what needs to be done. It will get the inner and outer small (right) side bearings, and all the seals replaced. I'll put more pics and details in here as it is done.

A few more things done today.

Hint #9 - If you are not doing a total tear down like this one lay some type of shop towel or otherwise over the bearings to keep debris out of them before you start cleaning.
Hint #10 - When cleaning off the old gasket old fashioned is best. I have an old Craftsman gasket scraper (left of the trans in the first pic) that I keep sharp, a razor blade type works well too.
Hint #11 - After scraping it use at most a knotted wire wheel with light pressure, or a less aggressive means on an air or electric grinder if you have one. If you do a test spot you should still be able to see most all of the marks from the mill used to true up the housing. We want to clean it, not damage it or make in untrue by removing material.
Hint #12 - Make sure to get all of the rust off of the entire surface, especially areas that were not covered by the gasket like the protrusion for the rear hitch, etc.

** Whatever you do DO NOT use a flap disc, grinding wheel, a Roloc style disc, or anything that removes material. These eat material, cause an uneven surface, and produce a fine dust that can get in places you don't want it. All vehicle, small engine, transmission, etc, manufacturers have had service bulletins on not using the Roloc style since they came out many years ago because they produce a fine dust that the filter will not catch that will cause damage, and cause uneven surfaces that become a sealing problem. I understand these transmissions will prob handle the dust but I don't even keep Rolocs in the shop. Fast is not always best...

Hint #13 - After cleanup check all of the bearings again and make sure all of the needles are still there, then pack them with your finger with a light lithium grease to make sure they stay put while moving the cases around, or reassembly. I use the white because it will dissolve easily into oil once it is filled and parts start moving, holds well, and it won't run all over the place like other prelubes.
Hint #14 - If you care about looks, sometime before the transmission is put back together you can clean up and paint all of the outside pulleys, shifter, brake drum, hubs, etc so they will have time to dry and be ready when you are to put them on.

Today's jobs were finishing clean up of everything, (including the mess on the bench and floor), and blasting + painting the external parts so they would be cured when I'm ready for them.

I thought I put a little update in here last week with the bearings in but I guess not oops.

Hint #15 - If you painted the hubs you can check the fit on them now or later, but do it at some point and get them where they slide on and off easily instead of trying to hammer them on, you'll be glad you did. I went on and cleaned the extra paint out from inside the hubs and made sure they went on easily when I had a few extra minutes last week.
Hint #16 - Clean up the drain plug and check for damage, then thread tape it and put it in. If the thread tape unravels when installing then the tape was put on in the wrong direction. They also have to be pretty tight to not leak so I use what you see in the pic to tighten it.
Hint #17 - The inside bearing is easy and prob doesn't need explanation, just don't hammer it or put pressure on the center race to put it in, it could damage the cage.
Hint #18 - Just for fun there's a pic with the dipstick in to show where the fluid level will actually be when filled, the level is above the left side plug which isn't used any more on these but was never removed from the mold.

I'll do the outer bearing in the next post here shortly.

I'm not sure where the day goes sometimes but it up and went again. I'll do the other updates in the morning...

Moving right along lol... This post mainly deals with the outer axle bearing.

Hint #19 - You will have to turn the trans over or on it's side to do this so securing the gear assy is a good thing to do. This time shift the shift fork into the 3rd gear position, it's the shift fork closest to the rear and it should be in the full down position. Then secure the splined pinion gear with a rubber band. (I learned this old trick from someone in the late 70's that did a lot of manual transmission work.) These 2 tricks will hold everything in place while the case is rotated or flipped. See the 1st pic.
Hint #20 - This bearing has a very tight fit to hold it in place, there is no shoulder or clip to hold it in. Clean and check the bore, get it as clean as possible and lube the bore and outer race of the bearing before installing. I use a wire brush on an air grinder to do this like I do with all inside bores, and lube with light (white) lithium grease.

** DO NOT take a hammer to this type of open needle bearing. If you think you are going to find something that fits these type of bearings and just hammer it in there then you may as well quit now and take it to someone who can install it properly, it will not survive that type of install. If you hammer it it you will find that the outer race has collapsed enough that the bearing is locked up and you will have to drive it out and throw it away...

** A simple bearing press can be bought at some local parts houses, or are easy to make yourself. I made this one years ago with a piece of 1/2" threaded rod and a heavy meal plate that can be changed as need be for each situation.

Hint #21 - The bearing should be installed with the more squared end with the numbers, manufacturer, and ID facing outward where you can see them, the other end will be more of a roll with no ID on it. Install the bearing with the bearing press. The bearing is 1.250 (1 1-4") so once you get it flush you will need a 1.240-1.245 adapter to recess it to a depth of .30 (about 5/16") or close to it to allow for the double seals. The seals need .25 or so to install them where they will be flush with the case.

** If you use something too small it can still crush the bearing casing into the needles making it unusable meaning you have to drive it out, throw it away, and start over... If you use something the same size as the bearing (1.250 or 1 1-4"), then you have to deal with getting it out... If you can't find something that will work use something that starts at 1.250 or 1 1/4" and take a little off of it. My adapter is 1.243 and has almost no play when in the case but spins freely and comes out by hand.

** I measured and scribed a small mark at .30 on my depth adapter before setting it on the installer so I would be close to right the first time. It is the 5th pic but I couldn't get a good pic of the mark. If you go too deep just reverse everything on the installer and move it out a little then recheck everything.

Hint #22 - Check the depth of the bearing, mine is close enough to .30 as the seals only really need .25 and will be easy to install without hitting the bearing.
Hint #23 - Check the bearing, you can stick your finger in the new bearing and make sure the needles still roll freely, if they do then you are good and haven't damaged it installing it. If you can't get them to roll around then drive it out and throw it away unless you want to damage the axle or do the job over again soon...

This is the most tedious part of the job so I spent the most time on this post trying to make sure you don't have to yell, scream, cuss, or do whatever you usually do sometimes when you have to start from scratch over and over lol.

It gets really easy from here.

Hint #24 - Install the reverse idler gear, put some lithium grease on the end with the shoulder, then install with the shoulder facing down.
Hint #25 - Put grease on the case around the surfaces where the gears will be going back in.
Hint #26 - Put the transmission in 2nd gear, it will be in the up position (fork toward the rear), and test fit the cluster, it should go right in. If it does you can spin things around and make sure there is no binding, then remove it.
Hint #27 - There may or may not have been a thrust washer on the bottom below the large pinion gear. (Prior to 1973 the thrust washer was welded to the gear) This one had one and it goes in now. Put grease on it as well to hold it in place and prelube the shaft end.
Hint #28 - Drop in the pinion gear making sure to not move the thrust washer out of place.
Hint #29 - Install the cluster.
Hint #30 - Put the 2-3 shift fork back in the center (neutral) position.
Hint #31 - Install the axle assy, make sure the nuts are in the up position, see the pic.
Hint #32 - Recheck for proper operation. Everything should spin freely in neutral, check in all gears in both ranges by shifting the forks one at a time manually, then put the forks back in the neutral (center) position.

Final case assy.

Hint #33 - There are 2 guide pins shown in the 1st pic. Make sure they are very clean and slide in and out of their locations easily by hand without any lubrication. If using permatex for a gasket like I do there can be no lube on the case at all or the permatex will not seal properly.

***** This is why I use the white lithium as prelube in most all applications unless otherwise specified by the manufacturer. When using permatex for a sealer all surfaces must be clean and dry when applying and assembling with it. Most other prelubes are thinner, can run, and can get places that you do not want it to be during assembly causing you to have to possibly do part of the job over again and none of us want to do that...

Hint #34 - If you are replacing the brake shaft seal this would be an easy time to remove it.
Hint #35 - Prelube all shafts and places where shafts contact the casing being sure to not put any lube on the guide pins.
Hint #36 - Put the guide pins in the gear side of the case.
Hint #37 - This part is not necessary but something I always do. You can set the top of the case on and check to make sure it drops on easily, then spin the shafts to do a final check that everything moves freely, bolting it together does not need to be done. If it looks and feels good the upper gear case can be removed again for the last steps.
Hint #38 - Prelubing does not need to be redone after test fitting.

Case sealing steps. I use Permatex (brand name) permatex Ultra Black on most everything oil sealing wise. It is the best they make, does very high temperatures, and is made specifically for making or sealing gaskets in any type of oil application.

Hint #39 - We want the case clean as possible and completely dry with no residue. Some brake cleaners but not all, carb cleaner, lacquer thinner, MEK, and some other cleaners work well.

** O'Reilly brake cleaner is the same as carb cleaner according to the MDF sheet in a brake cleaner can. I buy it because by the case it is the same price as carb cleaner and comes in a larger can. AutoZone brake cleaner is not recommended, it will leave a residue, drys much slower, and does leave a light residue. You can tell it is not carb cleaner by the way it cleans, dries, and smells. Those are the 2 main parts houses I've used in the past 28 years for cleaners so I'm not sure about the other brands.

Hint #40 - Spray the cleaner on a rag and wipe down both surfaces until they are clean and dry. Do not spray it on the sealing surface getting it everywhere, it can clean off prelube and splash more residue on the case sealing surfaces.
Hint #41 - Put a thin layer only on the upper case and spread it evenly with your finger being sure not to let it get to thin. A little too much is better than not enough.
Hint #42 - Put the top part of the case on and install the 6 bolts and nuts without tightening yet.
Hint #43 - Tighten the bolts starting with the center 2, then the last 4 in an X pattern, where you start the X pattern isn't important. If you want to torque them you can take them to 35 ft lbs.
Hint #44 - Let the case sit overnight with the seals out (if removed), the fill plug and shifter removed so it can get some air and dry out well before the next steps.

** A nice bead will be in the last pics. You want to see it outside the case and it will be about the same on the inside making a good seal. If there's too much that's ok, too much is better than not enough and it can be trimmed easily after it dries without making a mess. Only a lot of experience or OCD will get a nice bead every time so keep practicing.

Bolting the transmission up.

Hint #45 - Put the shifter in temporarily and check operation through all the gears in high and low,then remove it, yes again lol...
Hint #46 - If you haven't already, take out the plug on the lower left rear, clean and inspect it, then thread tape it, if painting don't install it yet.
Hint #47 - Do the same with the plastic dipstick piece, don't install it yet.
Hint #48 - Make sure the roll pin is out of the high low shifter, it will be reinstalled from the rear when the transmission is bolted back up.
Hint #49 - The transmission is ready to put on the frame now, install it and make sure to put the high/low shifter on the shaft as you do this, it won't go on the shaft after the transmission is bolted up.

Painting the transmission.

Everyone likes what they like and that's fine, you should have what you like whether someone else does or not, it's your tractor so do what you like. You can just put red paint all over it like they did a most of them from the factory, or you may have a color scheme you like. I have a color setup I use and everyone seems to like so that's what's here. When I do things the way I do there's no mistake the shafts have been polished, it has new seals, new case hardened axle hub locks and jam nuts, new shifter set screw, the side plug has been out and thread taped, etc, etc, etc. If I just put it all back together and spray some red paint all over it they won't see that what was said to be done has been done. I've done customer work for many years and the reason they don't go anywhere else is that the trust is earned when peeps see it is truly fixed, can see you did what you said you would do, and they got what they paid for. It takes a little more time but it will make your work speak for itself and others will want you to do things for them, if you do it for a living your business will explode, trust me I know... It's also nice to hear peeps go "wow" or say "I didn't expect it to be that nice" all the time.

Moving right along... The key points are below -

** The reason I put the transmission on the tractor first before finishing up and painting is to balance it so I can do the rest on the forklift, I use it more for a portable lift than anything...

** I run over the transmission with a knotted wire cup brush on a grinder to smooth things up a little and especially get rid of all of the factory runs so it doesn't look like I did a sloppy job, painting over the factory runs just makes shiny runs... What I use is in the 1st pic.

** Also, if there are any war scars on the end of the axle shafts this is a good time to clean them up if you haven't already. I use a flap disc on a grinder, it doesn't leave a lot of marks like a regular grinding wheel, but anything is better than any damage from the pulling of the hubs...

Hint #50 - The transmission alone will be painted before any other assembling following the steps below.
Hint #51 - I slide the old seals on the shafts without installing them to keep paint out of the bore, then tape up the shafts. I like the red dots on the end of the shafts so I just stop taping at the edge.
Hint #52 - Paint the transmission.
Hint #53 - Let the paint cure and when it has (depends on what you use) unwrap the shafts and pull the old seals off.
Hint #54 - Check to make sure there is no paint on any of the shafts.