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Mgryder1

Charger 12 transmission

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Hey guys, this is my first post and I'm sure im going to ask some questions that have been hammered to death so please keep in mind that I have not yet fully learned how to navigate the site.

A little about me, I enjoy woodworking, (learning) metal working, welding, etc. As a hobby I enjoy restoring machine tools, lathes, drill presses, band saws,etc. I've never considered myself a motor/ gear head so I'm faced with a steep learning curve with my charger 12 resto.

About my tractor, I pass a salvage yard on my way to and from work everyday. About a month I saw a rust bucket wheel horse for $50. It appeared to be mostly intact but obviously needed a ton of work. So against my better judgement, I decided now would be a good time to expand my horizons with regards to restoring old American machinery and paid the man $50. From what I've read, I have a 1972, 1-0402 model. So far, I'm doing what I know how to do which is take it apart and do body work and bust rust. I have taken a ton of pictures and just yesterday I tore the rear end out and right away noticed that one axel and hub had been replaced at some point. The original axel appears to be in decent shape but the original hub is another story...the keyway where the woodruff key makes contact actually looks like it's been broached out...I'm guess the hub is much softer material than the axel and key. I have a question, would it be worth a shot to turn the hub 180* and broach a new keyway and tap a new set screw? It's worthless the way it is so I don't see harm in trying...you guys tell me what you think. As far as the axels go, there seems to be to be a lot of side to side slop...(forgive me if my terminology is wrong) I tore apart the bull gear that contains all the little pinion gears and the splined gears that go on the axels do in fact slide on the axels 1/4"-3/8"...is this normal? The snap rings or axel splines don't appear to show any wear. In this part of the transmission, I've not see any "red flags" so this has been decent news. I do have questions about axel seals and the brake shaft seal. It looks like the 1 5/8x 1 1/8" seal is available but I've been unable to find anything on the brake shaft seal. The axel seals were shot but I dont know about the break seal...I'd like to replace it since I have it torn down. As far as what I think is the "hydro" part...is there a way to bench test this? Before I took anything apart, I jacked up the rear end and put it on jackstands, put a pulley on a shaft and stuck it in my drill...I then put a v belt I had laying around on the transmission drive pulley...I was able to hold the drill and turn the transmission pulley but I got no motion out of the wheels. Screwball idea, but it all I could think of. Since I was able to turn the transmission pulley at a decent rate and I got no rear wheel motion, does this mean the hydro is shot? I tired this test in forward and reverse and I got nothing.

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1-0402 is a 1972 Charger 12 with a 90-2046 Sundstrand Hydrogear power unit.  When you did the "drill" test, (1)was there fluid (oil or ATF) in the gearbox  (2)was the push valve open or closed (3) who was manning the motion control lever for fwd / rev motion and (4) was the parking brake in up or down position. 

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Yes, there was fluid in the gear box...was there enough? I don't know. The push valve...is that the 7mph deal? That was closed. By manning the lever...what do you mean? Does this need to be held in place? I do not believe the break was engaged...I had the break leave disconnected so I tried it in the up and down position.

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I guess what could really help me at this point is if someone, in a nut shell, explain how the hydro part works. How does it turn the gears?

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the push valve (tow valve, free wheel valve) is atop the hydro unit.  

Fluid level must be in the operating depth range as indicated by the dipstick on the gearbox.

If the motion lever was in neutral, wheels would not turn.  Push forward on the lever for forward motion.

 

 

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Not sure if there is enough time in one day to explain how the hyd pump drives a SMALL gear (shown here) and that gear is connected to other gears in the trans, eventually delivering power to the wheels. Other hyd lines go to power the hyd lift for the mower deck and / or dozer blade, all from the same hyd pump.

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At the end of the day, I don't want to go to the trouble of restoring the hydro (cosmetically), reinstall only to find out that it's junk. What should I do?

Is this something a rookie should attempt to tear down and inspect? Like I said in previous post...I have experience with machine, just not transmissions and engines!

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The only way to find out if the tractor is junk is to start it and run it for at least 30 minutes.  If the engine doesn't smoke, then step w would be try the ground-power of it.  It would be a good idea to change the OIL FILTER before testing the trans, but you've already stirred up the oil so that may be pointless.  To test the ground-power, drive it around the yard forward and backward for 1/2 hour or so to bring it up to an operation temp.  If, after that long, it seems to keep its power, then I'd say it is in useable condition with or without cosmetics.  If you can see fluid leaking around the rear axle seals...LT or RT side, that isn't too bad as seals can be replaced without tearing the trans apart.  If you begin to see oil leaking from around the hyd lift control and/or hyd lines, this can also be easily repaired. 

The most serious issue)s) would be a broken gear in the trans or a loss of power when its warmed up to operating temp (the 1/2 hour period).  If you notice significant power loss when warm, then the hyd pump is worn out and needs overhauled.  I've overhauled several of these....for a fee, of course.  If there is a broken gear in the trans, you'll either feel it or hear it, or break the left or right side of the trans case....maybe the bottom side.  That, however, is a catastrophic event seldom to occur.    

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On a sidenote, awesome work on that hood, if you restored other machinerie you should be able tot tackle that trans

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Don't know if it matters but the normal rotation of the hydro pulley is counterclockwise. You would need the drill in reverse. Here's how I did one with another tractor.

 

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What it sounds like to me is that my drill test wasn't exactly a fair test...I left too many variables. It really wasn't THAT much trouble to pull the pump so I think the best thing to do would be to put the transmission back together and follow your advice, Dave. It will have to wait as my tractor is in about 150 pieces at the moment, ha...I have plenty of other areas that need work. Thanks for the compliment C-101...it took a lot of heat and a lot of hammering but it looks decent now. 

 

Do any of you guys have advice on my axle slop, wheel hub, and seal questions? As I said before, it looks like the axle seals are available from multiple sources but the break seal is discontinued. The book I have said the shaft is 1/2" diameter but I have no idea on the OD. I don't want to pull the old seal until I can find a replacement b/c as far as i know the brake seal I have is working. I dont want to find out the hard way that it needs replacing. Other than the gaskets, are there any other seals in this transmission that I should change (I dont have the transmission in front of my at the moment)?

Edited by Mgryder1

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Here is a pic of both side of the trans case.  There is no 'brake seal' as the automatics of your vintage don't have 'brakes'.  What you MAY be referring to is the Parking Pawl seal, as shown in the lower left of this pic.  I think that seal is 1/2 x 3/4 but will have to size mine to be sure.

A bigger concern is the parking pawl itself.  There are two types each prone to wear-down and the shavings contaminate the oil promoting wear-out of brass parts.  

Here are two types of parking pawls....you'll have to look inside to see which is yours.   I have a CAST IRON one but not the stamped STEEL type....you can have it mig-welded back to original shape.  

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Mine is the stamped type...I didn't inspect for wear but I will when I have it front of me. And yes, I believe you are spot on with what I'm trying to say. I don't know that me seal leaks but while I can get to it, I'd like to replace it. If you could provide a measurement or a replacement part number, that'd be great. I don't want to pull mine if I don't have a replacement handy.

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I copied and enlarged your pic and the PARKING PAWL looks to be near perfect. The seal is part # 5959 and dealers should have it. You have to take the lever off of the shaft (outside of trans) by driving the roll pin. Then, push the park pawl thru the hole and withdraw it.

While you have it apart, open up the differential and inspect it for wear / damage. IMPORTANT....note the orientation of the bolts holding it together and DON'T put them in backwards. #2... Use LOCKTITE on the nuts (should be 5) to ensure they don't come apart under use / load. OEM uses BLUE LOCTITE.

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It would behoove you to take the pump off of the hydrogear and have a look at it.  Changes are, it would need some service, after 40+ years of use.  It is spring loaded and MAY be difficult to separate from the hydrogear so use a thin putty knife blade to start at one corner and work around ...carefully.

How do the seals look on it....I know the replacement seal #s, but the one on the end can be a PITA. 

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The 5959 part number has been discontinued and I have been unable to find a suitable replacement. I called a toro dealer yesterday just to confirm they didn't just change the part number...asking you guys was the next step I took. I have already taken the differential apart and everything look pretty good (to my untrained eye anyway) I did snap a picture before I took it apart. I can see the direction of the bolts from the first picture. Is the "spring" just a spacer so the axels don't hit together?

The 5959 part number has been discontinued and I have been unable to find a suitable replacement. I called a toro dealer yesterday just to confirm they didn't just change the part number...asking you guys was the next step I took. I have already taken the differential apart and everything look pretty good (to my untrained eye anyway) I did snap a picture before I took it apart. I can see the direction of the bolts from the first picture. Is the "spring" just a spacer so the axels don't hit together?

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When you start talking about spring loaded...that sounds like you need to know what you're doing in order to put it back together properly...am I wrong on this? It's my feeling that lots of pictures and common sense can only get you so far which is what I've been operating on so far. I'm a do it yourself kinda a guy and I don't like paying guys to do things I can do my self but I need to know when to say when. Some things are better left to a professional or an old timer. I just have this image in my head of poping this thing open and springs and valves flying accross the shop, ha.

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was the spring there when you took iy apart,you have a limited slip differential,because there are 10 pinions we know its a limited slip.the spring is usually what breaks in these diffs,as far as your hub I would see if a machinist could broach you a key,if not you could post in the wanted area for one,but im sure you want to see if she runs and moves before you spend too much on her,but there are lots of used parts available for these tractors and we have some very good guys supplying these parts here on red square

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I have a broach set at work so I went ahead and just did it. I'll drill and tap the set screw something this week when I get time. I may add another set screw or make a collar for this hub to give me some more meat to work with. You can see in the picture the new keyway and old worn out keyway.

About the spring, it was like that when I took it apart...supposed to look like that? All the limited slip stuff was over my head...if you would briefly explain what that is.

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Forget everything about the limited slip (it looks like your diff is assembled properly, so dont worry about it), the spring comment was related to your hydrostatic pump assembly.

 

 

I'm going to leave this to Dave hes the resident expert on older Hydros, so follow his advice. :handgestures-thumbupright:

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Your 10-pinion LSD looks good, from the pics. Have a VERY CLOSE look at the two parts (A) for hair-line cracks, a very common problem. Note that the end caps are different in depth / length. The SPRING in the middle is what gives the whole apparatus the LIMITIED SLIP attribute and it must be positioned correctly. There is a YouTube video of the reassembly of this LSD. It is kinda slow and the guy fumbles parts a bit, but it is the best source of How-To that I've found.

Yotube video:

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Edited by daveoman1966

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This is what I meant by spring-loaded. When you take the 4 boults out of the pump housing (holding it to the hydrogear bse), it will be spring-loaded, but stuck fast by the old gasket.

CAUTION... when you pull the pump away from the hyd base, DON'T let the cylinder drop out of the pump. Lay it on the horizontal and SLOWLY separate them. Then, tilt the pump up slightly and wiggle it off of the shaft and try to keep the 9 pistons from dropping out of their cylinder bores. This can be tricky...to say the least.

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I noticed in the video that he has to work to get his spring back in....and the picture you posted shows there is a gap between the ends (just as a spring should have). Mine almost butt together and my spring just falls into place...I can bend it open to make it fit tighter but what concerns me is why the heck its like that in the first place.  Also in the video he showed thrust washers...I dont think I have those and I don't see them in your pictures.

 

I took a better look at my "park paw" and there is a decent size groove taken out of the surface that meets the gear. Like its been milled out. I also found light metal shavings in the strainer/screen. That cant be good....the shavings are probably the parking paw. I have a mig welder so I'll fill in notch and grind it back smooth maybe tonight or this weekend. Ive still be unable to find that shaft seal (P/N:5959) but pulling the shaft will give me a good opportunity to visually inspect the seal. 

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