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formariz

Need advice on RJ tranny rebuild

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So i  did my first tranny rebuild on a spare tranny that was around for years. All new bearings and bronze sleeves. A major issue was that axles were really worn under bronze bushings, so I turned them around and redrilled the outer ends for the roll pins inside differential. Everything worked out ok. When I put it back together and tightened cover bolts I noticed that i could no longer turn it by hand, so things were just too tight inside.Added a second gasket on one side, retightened and it then turned freely.

 

Mounted it in a tractor and tried it on jack stands. Everything works as it should. Now for the problem.  When in neutral I try to move both wheels foward by hand it is very hard to do. Doing it backwards they wont move at all, therefor making it impossible to push tractor around. Also when up on stands and i push both together foward seems to be a slight "grinding" coming from the differential area.

 

Is it possible that things are still too tight in there?

 

Any advice greatly appreciated as always.

 

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Now it is to be expected for the tranny to be initially tight after a rebiuld but from what you describe that sounds a bit to tight or an iternal issue.

 

Keep in mind that when you are turning the tires you are not engaging the natural gear reduction that the motor feels... so that adds to the "feeling" of tightness. You should although be able to push the tractor in both directions with minimal ease.

 

You should only need one gasket on each side.

 

When spinning the input shaft in all gears (including reverse) does it feel as if there is a binding situation or do you hear any rubbing/griding?

 

Did you hone the new axel bearings to fit the axels?

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Spininig input shaft in all gears  one does not feel any binding or hear any unusual noises. Feels a bit thougher than before rebuild . The only unusual noise i hear is when attempting to move both wheels simultaneously. Then there is a more of a hard rubbing noise coming from differential area.

 

The additional gasket did solve initial problem.

 

Yes i honed bearings. They slipped over axel snug but with ease.

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The sides of the tranny are not pinned so did you use the correct ground bearings in the two required locations?

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Thought about that. Possibility that i may have a incorrect bearing in wrong place sticking out a little. I know i have the correct bearings needed but i did get a little confused as to where which went since i removed them all a while back and neglected to mark them.

 

Without referring to their numbers essentialy there are open bearings and closed bearings. I would need an illustration showing  were each one goes.

Edited by formariz

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There should be no fully closed/sealed bearings... the standard R12 bearing has no play in the race... the ground bearing has a little slop in the race to take up the slack in the side covers. Without that play issues with arise. I beleive the tranny exploded view does not differentiate between the two style of bearings but don't hold me to that...

Edited by VinsRJ

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Now the plot thickens. Will post pics and specs of bearings I got a little later .

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There are 4 open bearings (S8K) and 3 closed bearings (NICE 412-35).  2 of the open bearings support the input shaft with a 3rd one on the end of the spline shaft...the 4th one goes on the brake shaft end of the mushroom gear.  The closed bearings go...1 on each end of the cluster gear shaft and the 3rd one under the large end of the mushroom gear.  There may have been a thrust washer under the closed bearing under the mushroom gear.  The open bearings measure 5/16" in height.  The closed bearings measure 3/8".  The inner bearings should be seated flush with the metal ring they sit in.  It is possible to create tightness by seating them all the way in.  I don't know which bearings you actually used, but if any of them measure 7/16" or are not seated properly, your trans will pinch when bolted together.  Vince is correct...you should not have to double up gaskets.

 

On jack stands and in neutral, when you rotate one tire, does the other one rotate in the opposite direction??  Looking to make sure your differential pinions are alternated one up and the next one down.  One other thing comes to mind...are the roll pins in the differential the correct length and are they centered in the holes...both the axle gears and the pinions??  :eusa-think:

 

If the roll pins in the axle gears are not centered, they can interfere with the differential pinions.  :)  That would create the systems you are talking about.

Edited by stevasaurus

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Tires do rotate in oposite directions. It functions perfectly in all aspects but the mentioned. I been running it with the engine on jack stands. its just when one tries to duplicate the action of pushing tractor around that I encounter trouble. I am pretty certain that i have the correct bearings. Very possible i used a wrong one for a specific area. However I really did not notice any of them really protruding fom housings. I am going to verify that.

 

Now, as for the roll pins being exactly centered , i know i would not leave them way off but indeed they may not be perfectly centered. The odd thing is that i tried everything several times during assembly and did a dry assembly without tightening case bolts, and everything always worked fine. Unfortunately it did not come to me to try a neutral, moving both axles at same time action, since all other tests worked perfectly.

 

I also used the same roll pins that were in it before.

 

Just checked and i did use the specified bearings, now i can only find if they are in the correct place once i opene it later tonight.

 

I still have the old bearings and odly my tranny had 3 open bearings and 4 closed ones!

Edited by formariz

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I appologize... I mixed the bearing names up... the R12 is a Ground Bearing... the NICE bearing mentioned above is an Unground Ball Bearing... becarefull calling them closed bears as they are not closed.

 

Attached is the Unground Ball Bearing

post-1597-0-84248700-1415908851_thumb.jp

Edited by VinsRJ
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I hope Vince still gets in here, he is very good at this trying to figure out thingy.  If you have 3 open and 4 closed bearings...someone has been in there before.  I am wondering which differential you have in that trans.  How many teeth are on the small gear on the mushroom gear.  I think it is either 8 for an early RJ, or 11...just wondering at this point. :)

Did you have a thin washer under one of the bearings when you tore it apart??  Most of the pinching situations that I have ran into are because of the bearing under the large gear on the mushroom gear.  If that bearing is tapped down tight in it's seat...it will pinch...unless you have that washer under it.  When you take it back apart, look on the bottom of that gear and see if it has been scrapping on the ring that holds the bearing.  Measure the thickness of the 2 types of bearings you have and check to see if they are in the places I stated above.  That thickness is critical in the right places...as you found out by just adding an extra gasket...does not take much.  You may only want to torque those bolts to 12 - 15 ft lbs.

Just thought of something.  The bolts for the plates are 1/2"...except for one.  The one that holds the little piece of steel for the spring on the brake shaft side is 3/4".  If you have a 3/4" bolt in one of the wrong spots, it will rub on just about any of the gears...but will especially rub the bottom of the large part of the mushroom gear if it is placed on the input side of the trans.  (I'll bet that is what you have going on)...that would explain all of what you said.  :)

post1.txt

Edited by stevasaurus

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I will check soon but I am sure I have the 8 teeth gear. I looked at long enough since it had so much wear and I was thinking about your video regarding the later upgrade differential. There was one i believe on Ebay, NOS but it was missing its counterpart.

 

I did not find any washers however I did notice that one side was polished under one of bearings like shaft went through bearing and was rotating against tranny side. I don't remember however which one it was, also that was the only bad bearing since it was frozen.

 

Did torque all bolts to 15Lbs, however i never did notice one bolt was longer. That certainly could be an issue.

 

Will be drainning it and tearing into it again. Tedious but I just love to learn new stuff all the time.

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Vin

 

When I mentioned a closed bearing it was just that it does not have the spheres as exposed as the "open" bearing. The "closed" ones are just like the one you depicted.

 

I am still unsure of the difference between a ground and an unground bearing and have not been able to find a clear explanation. Perhaps you can enlighten me on it.

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That is why I call them open and closed,even though it is not correct, because everyone knows what you are talking about.  I Googled and did Wikipedia for the ground and un-ground thingy, but I don't remember what it was about.  There was not a lot of information.  :eusa-think:

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From my understanding of what I read it has to do with how precise a bearing is machined but I am not positive that it is all to it. Perhaps some of our machinist members can chime in and enlighten us.

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Well, we could do it like this...the one with the 1/4" balls (S8K) and the one with like 1/8" balls (NICE 412-35)... :)

 

Did you replace any of the bearings (you said you had one that was froze) ???  If you bought some new ones...what did you buy??

 

The thickness is critical.  I know some guys like to use the R-12 bearing, like the picture Vince posted above.  It looks like the NICE 412-35 bearing, but it is different.  The NICE bearing is 3/8" thick.  At Motion Industries, they show two R-12's...one is 5/16" and the other is 7/16".  The 7/16" is too thick and will pinch the trans when bolted together.  The 5/16" R-12 will work, but you may want a 1/16" thrust washer under it. or just seat until flush.  :)

Edited by stevasaurus

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Steve, does that mean I have to unlearn what you taught me and relearn the new terminology? :roll:

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I did replace all the bearings although now i kind of doubt that logic since only one was bad. Like the old saying "if its not broken don't fixt it".

 

I used  NICE 412-35V which is 3/8" thick and  FAFNIR S8K which is 5/16" thick.

 

Found also for future use an equivalent to S8K which is a KOYOEE6C3. They are identical in all dimensions.

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OK...I have waited all day and checked out this thread a number of times today....what did you find???  :)

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OK...I have waited all day and checked out this thread a number of times today....what did you find??? :)

Sorry. Had someone pass away in the wife's family do I did not get to it. Tomorrow is the viewing and funeral on Monday so I am not going to get to it until Tuesday .

I also want to get to it as soon as possible since I can't stop thinking about it. I really appreciate all the input on this.

Edited by formariz

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I'm sorry for your loss...this has been a not so good Fall this year...my prayers with you and yours. 

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Sorry for your loss...

 

 Just as Steve has said: The 5/16" R-12 will work, but you may want a 1/16" thrust washer under it or just seat until flush.

 

One thing that has not been mention is... make sure you lube up all the bearings and bushings. I use either engine assembly lube or white grease... both will break down once the gear lube is flung around y the gears.

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Thank you everyone for your condolences.

 

I still have not had  a chance to work on it. Hopefully soon.

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ground and unground bearings in your transmission

 

ground bearings are precision ground to a mirror finish for very tight size tolerance and fit

unground bearings have a larger size tolerance and fit they have a much wider range of misalignment they can handle over the ground bearings

you can feel this in your hand by the movement between the inner and outer bearing races

the wheel horse 3 piece trans cases are not pinned in alignment like the newer cast two piece trans cases when you look at a disassembled 3 piece trans

you can see where the different bearing types are used. The ground bearing are where they can be kept in truer alignment like the input shaft and the

unground style is used to take up any misalignment between the case pieces side to side

 

you can buy both bearing types from mcmaster-carr in the correct sizes

 

Brian

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