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Broke into my original RTO-12513 transmission yesterday and it needs a bearing kit for sure. Lots of grit stuck to the magnets with all gears and hard parts looking good. No excessive backslap or anything out of the ordinary at all. Transmission was never ran low on oil so just high time usage.

In case other's have the onset of the same disease as I, (CRS) this transmission is from my 1980 R-612ST and was pulled to change a clutch. I installed a different transmission along with a replacement clutch assembly and machined flywheel. This transmission always had a "howl" in the low range. Not a grinding or clunking, just a "howl" that went away immediately when shifted to the high range. The overdriven section was always quiet not having the characteristic "whine" the series was known for. 

One thing I noticed right off after pulling the auxiliary section from the main case is the countergears are not "timed" correctly. There are bright orange timing marks on the mating gears and the right countershaft is off by one tooth. The left countershaft engages it's marks correctly. Someone has obviously been into this section in the past as there is an "Associated Diesel" reman tag affixed to the main case. I also found a syncronizer spring against the magnet in the rear of the main case. I'm going to bust it apart and repair any obvious damage found, then slip fit onto a test jig to run it. The front section seems alright and rotates smoothly though all gear selections so will go through it to have another ready spare.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Edited by Rob
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So they will work while not timed correctly? We had a 12513 in the shop many moons ago, a guy pulled the rear section and made some repairs. He put it back together and took it down the road for a test, made it about 1/4 mile and the thing exploded...large holes in the outer case. I wondered if he didn't get it timed correctly.

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3 hours ago, h67st said:

So they will work while not timed correctly? We had a 12513 in the shop many moons ago, a guy pulled the rear section and made some repairs. He put it back together and took it down the road for a test, made it about 1/4 mile and the thing exploded...large holes in the outer case. I wondered if he didn't get it timed correctly.

I have to assume so but will run noisy. This one is actually two teeth off. My wife is on the computer and I'll upload a couple photos in a bit. 

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they will run but do not like it

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Here is a photo of the right countershaft and the main drive gear. The countergear plainly has a "0" stamped into it and is painted over orange. The drive gear has a "hashmark" stamped into it and is also painted over orange. The "gullet" between the gear teeth is painted orange as the rebuild manual shows. These marks should align with each other during assembly but do not. The left countershaft aligns with it's marks perfectly so someone wasn't paying that close of attention during the rebuild.....

image.jpeg.5944f351d02a19eb3a73993a8d9947f7.jpeg

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Rooting around the shop this afternoon and ran across this PTO and adapter assembly. The stud kit is there also. This PTO is a two speed reversing unit, (Chelsea 321 series) I've had for many years. The adapter had wear in the shaft and I had both a new shaft, and the old gear ground, then installed a larger roller bearing in the gear. It is as good as new. It will probably go onto my B-673ST as it has a Duplex transmission and no PTO installed. I also have a 20K Tulsa winch this will power nicely as I think it will reside in the concave of the cab back panel.

  image.jpeg.33388511f758191d92af939513efa930.jpeg

Edited by Rob

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Ok maybe a dumb question but........ Why does it need timed?   Shafts are all round and gears are the same all the way around, right?    What's to time?      FYI I know nothing about trannys.   

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I know enough to be dangerous.  I'm thinking it has to do with gear/splines between all the shafts.  If you put a regular transmission in two gears at once, the input/output can not turn(can't spin a shaft at two speeds at once).   The timing of the splines(gears) is very close and you have to have both countershafts in exact time, if not then the sahfts are working against each other.

 

Am I close?

Edited by Freightrain

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1 hour ago, Freightrain said:

I know enough to be dangerous.  I'm thinking it has to do with gear/splines between all the shafts.  If you put a regular transmission in two gears at once, the input/output can not turn(can't spin a shaft at two speeds at once).   The timing of the splines(gears) is very close and you have to have both countershafts in exact time, if not then the sahfts are working against each other.

 

Am I close?

Very. There is a lot of gearing working together in these coupled with the reduction gearing taking place. I don't see anything hurt other than bearings are noisy when spun by hand so it may be something which can be reused after renew of worn parts.

In these there are countershafts in both the main, and auxiliary sections for a total of four. These have to be "timed" to their corresponding "main" shaftings and gears. Lot goes on to make it all work together.

I got part of the auxiliary section broke apart yesterday and so far have noticed no hard parts needing replacement. I'm going to finish busting it apart and cart it to my buddy at Fleetpride for his opinion before going much further. I've not found anything wrong with the main section at this writing.

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1 minute ago, fjh said:

If it were me I would rebearing / reoring and  Replace the syncro just cause your there! The trans will likely not assemble if not timed!  IF BY Slim Chance You Do get it assembled out of time IT WILL NOT TURN more than half a turn! IF By chance you don't turn it more Than one turn while you Are reassembling it can't imagine anyone that would do this BUT!!! you will likley be picking up Pieces off the floor in the first 1 foot of operation!

Just saying🙄

Hi Fred, yes it will go through a full rebuild in the rear section if I don't find something catastrophic in nature once it's completely apart. The syncronizer is shot as the springs have literally fallen out of it and the pins are very worn. It was run for I don't know how long with the one or two teeth off in timing, but I've owned the truck several years and only pulled it out to change a clutch. I had every intention of reinstalling it as it gave no problems but ran across the other one so installed it.

A full bearing and seal kit, (Fuller K-1862) is just about $600.00 which includes all bearings, seals, and normal wear items. It may require a snycronizer purchased separately as I've not asked and don't know. Regardless with the front section appearing good and this being very quiet in the overdriven selection I'd like to have it as another ready spare. Going to rebuild it right unless something bad is found. Should be able to get further analysis today or tomorrow.

I enjoy learning so in a sick and kind of twisted way I'm furthering my education which falls under the category or "Teaching a Rock to do Tricks".

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11 hours ago, Hobert62 said:

Ok maybe a dumb question but........ Why does it need timed?   Shafts are all round and gears are the same all the way around, right?    What's to time?      FYI I know nothing about trannys.   

Shafts free ends can be “wandering” when only committed into only one side of a case. Timing, in any trans i’ve worked on, only guarantees the cases will come together with shafts in alignment and bearings landing straight in their bores/cups/cones.  Never tried it without timing, but assume you can’t easily, if at all, make the cases come together(Mack) or insert bearings into receivers after case is mis- engaged (fulller). 

Agree with Fred, only gears that re-time every rotation, or couple rotations have to be close divisibles of each other. Worked on a Cat with a Perkins engine recently that took around 30 rotations before both driven accessory gear “branches” aligned simultaneously with crank timing marks. Every gear had different number of teeth. I painted them (timing marks) bright white and engaged the starter till the paint dots started rolling closer at engagement points. Pretty entertaining to watch them coming into and out of contact, dizzy work. Ended up with a battery charger eventually, for the sake of over-shooting. 

 

Edited by Mack Technician

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7 hours ago, fjh said:

Also  called the school of hard knocks!😁 It is fine institution ! I Attended many courses at that school The instructors Name was MURRPHY I believe He was a Lawyer At one point! 😉

You went there too????? That's my photo in the lobby labeled "Least likely to Succeed" prominently displayed. It took me three attempts to pass the preliminary entrance qualification exam and and equal number of enrollments to graduate. Personally I think they got tired of looking at me so passed me on through.

After meeting "Momma" there during lunch break and gettin sweet on her and she on me, things started to go downhill I felt. What really pushed me to front of the graduating class was when she came to visit me with a box of her favorite health food, (Bon Bon's) wearing her bright silver sequined jumpsuit and her right hip bumped against the classroom door jamb setting up oscillations as she looked, (as I best can relate) like a silver ball in a pin ball machine bouncing back and forth off the bumpers.

That woman continues to amaze me in so many ways to this day too.

Didn't get any more done on the transmission as switched over to some hydraulic cylinders I need to prove bad or good for an upcoming project.

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Rob talking about the snycro be shot if the pins are broken or worn bad there was a drive line virbration.Two things will break the three pins and that is ranging in reverse and drive line virbration due to ujoint angles or like.When timing or placing your paint marks on the gear you use the tooth that lines up with a tooth on all gears on that shaft and I have seen the factory mark in the wrong place.I built a jig years ago the check the timing on the front counter shaft of a 12513after we had a come back.What we found was on a trans that had been locked in two gears at once it had broken some key stock in the shaft and letbthe gears be out of time a small bit.So after that we would use the jig to check them and I can remember two we found with the key stock broken.

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Glenn we did a an 18 speed 4 months back guy thought he had a slipping clutch loud squealing sound when pulling b train couldn't see anything wrong with the clutch pulled the trans took the lid off found nothing!

Pulled the back section found both counter shaft gears had sheared off at the welds and were spinning on the shaft! I was Totally amazed it didn't end up scattered on the hyway! 

Furthering the school of HK at someone else's expense ! 😉 professor Murphy at work again !😂

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Hi Glenn;

When I got the truck the carrier bearing was sloppy for sure and I replaced it shortly after. I don't know about ranging in reverse and I've not done it as was taught it would destroy parts although not aware of what. When the driveline was still in the truck I could raise the driveshaft yoke about 1/16" up as the rear bearing supporting the output shaft appears to be worn out. With the rear off of the transmission and the output shaft rotated, the bearing feels "notchy" in rotation so definitely worn out. This is with the splitter engaged or freewheeling and turning only the rear bearing/gear and not the countergears.

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Forgot to post I had rotated the yoke many times and each time the right countergear timing marks aligned with the output drive gear mark, the left countergear was not aligned. The only time I could get them close is when I snapped the photo which had the left marks aligned. That photo shows the closest they would align to. I know the yoke was rotated in excess of 25 times before calling it quits. Thought I had a photo of the syncronizer and pins but do not.

Need to run into town tomorrow and pick up a fresh five of hydraulic oil and will get this auxiliary section finish knocked apart.

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Posted (edited)

Today I removed the rt. countershaft bearing which allowed the syncronizer and countershaft to move/remove and be reindexed correctly. Now when the yoke is rotated through about six rotations the index marks all align as they should consistent. I deduct from this exercise the transmission was assembled incorrectly. After pulling it the rest of the way down, (auxiliary section only) I packed the rear assembly and two tires I'd removed from my R-612ST earlier in the day into the back of old "Krusty". I had got out to the shop this morning and noticed a tire bead broken loose of the rim on the inside dual and had a known leaking valve stem in the rt. front so get them both addressed.

As I'm far too much of a wimp to swing a tire hammer, and after dropping them off at the tire dealer for repairs, I headed on over to the truck parts supplier. They looked at the parts, felt the bearings, did some preliminary measuring and thought as I that it just needed a bearing and seal kit installed. I didn't have the main section with me but I really see nothing wrong with it but will be gone through just the same. I did order a K-1862 rebuild kit and an A-4938 syncronizer assembly to replace the original A-4388. Supposedly the later is an improvement although they looked at the old syncronizer and thought there was nothing outwardly wrong with it. It did work fine but only one spring is mounted and the other two were in the bottom of the case stuck to a magnet? Never having of of these apart before I wrapped the syncronizer in a plastic bag as I pulled it from the shaft to not lose anything should it come apart, (it didn't) and I left it in the bag.

Upon getting back to the shop I decided it ain't quite as much fun wrestling truck tires these days as it was 30 years ago neither. I did get the rear rims trued to within 1/8" with a torque wrench by hand and the front rattle gunned down prior to final torque with the wrench. I then decided to go for a jaunt down the road a few miles to get all the gears exercised. I found out the bottom five are silky quiet in operation as is the upshift to high range and sixth gear position. When I flipped the splitter the transmission immediately went to neutral and I could not recover a gear. Getting off on the shoulder and selecting low range, all recovered well. I started off again and was at about 45mph and went to split to 10th gear and back to neutral with no recovery till stopping. Upon the third start from stop all upshifting went as it should. I shifted into 13th gear at about 60mph and it slipped in effortless. I then split to 12th, and 13th about 10 times in quick succession to get things loosened up and that must have done the trick as it shifts normally now. Given these are splash lubricated it was probably dry internally from setting so long. It does take a bit more effort to shift this transmission than the former as it's tighter which will probably wear in a little bit. The overdrive section is louder, (but not bad) than the original by far but I don't have the floor mat in the cab, nor the floor panel completely bolted down yet. With the road test done I'll probably finish it up complete tomorrow.

Edited by Rob

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Posted (edited)

Well son of a bitch that didn't last. Go out to the shop this morning and the tire I had fixed yesterday with a new Alcoa valve stem in the rim is flat. Fortunate the bead had not broke free so used the truck's air supply to inflate it enough to move from the back to inside the shop. After getting inside and bringing the pressure up to 100psi I soaped everything down and could find no leak. After a couple of minutes thinking what in the world could be the problem, I hears a "pfft" and then a steady stream of air release. Turns out there was a dried "thorn" stuck in the tread. After rolling over the floor jack and removing the wheel, I got to swing a tire hammer temporarily sidestepping my elderly and feeble frame stature and separate the tire from rim to patch the tire:

 

 

 

I don't think I would have patched this tire for road use given it's proximity. It is in the tread but very close to the sidewall. These tires were new in 1995 so far to old to use on the road but good enough for my yard horse.

Edited by Rob

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Rob thrusday I went to the tire shop for a slow leak in a trailer tire.Its cold so they pulled me inside and I go into drivers room so in a few the tire man say come take a look.The left steer tire was flat.I heard a air leak when I got out of the truck but did not take a look with all of the air hoses laying around.I guess I run over something in the last mile to the shop.

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Ya never know Glenn. The guy whom worked on this one yesterday submerged it in a large tank and it showed no leakage then. I don't have any thorn bushes on my shop property but I'm sure that's what it was and was very dry and brittle. Should have snapped a photo but didn't as once I pushed it out a bit from inside and pulled the balance with pliers, it crumbled.

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