Have a 1994 CAT 426b and the drive hub on the torque converter just failed, completely worn off. This was a rebuilt torque converter that was installed along with a new transmission pump 400 hrs ago after the same thing happened on the original t.c. machine has under 4000 hrs. Cat tech says this could be caused by bearing failure in the transmission and recommends new bearings in trans. I probably cannot afford to have Cat do the rebuild and once in the trans it should probably get new clutches etc so I am not doing this anytime soon again. Tagmann I read your posts about your rebuild and was thinking of getting the joseph industries rebuild kit. Was even thinking of rebuilding myself but never been in a trans before. Any advice would be appreciated.
Sorry, when you say "drive hub failed, worn off", I interpret that as, what I call the spout, chrome tube that has the drive tangs for the pump. Is that correct? Do you have any pictures? If that is correct, I would think there would be a flexplate issue as well. Is the spigot (bit that goes into the flyweel centre) still OK? It needs to be a snug fit into it's bore. With no signs of wear. In this situation, if all else looks good, I still fit the convertor & check the spout for trueness using a dial gauge. I would think you have some sort of alignment problem, between the engine & transmission. Dowels are usually used to locate the bell housing to the engine, problem there maybe?? If anything was going on inside the transmission, ie bearing failure, their would be other problems - metal in oil / filter, drive & noise issues. I'm by no means a CAT guru, but I do know my way around transmissions. Something is very wrong & should be obvious to a trained eye.
airman, thanks for the input, yes I am referring to the drive tangs, there is metal in on the magnets, some in the filter and I assume that to be from the drive tangs failing. No unusual shifting, noise or other transmission issues. The fit flex to converter is good and will find the measurements and post them be a few days. No issues with fit of bell housing or on the dowels that I can see. I will conduct a closer inspection of the flex plate. thanks
Mattm257, my stomping ground is Southern NH, but I will ask around.
craneinnovation do you rebuild transmissions? I get over to southern NH once in awhile if it is something that you can handle.
I probably would if I had to, but I haven't done one yet. Maybe give these guys a call? http://www.laceyrepair.com/index.html
Try Cameroto. There is a shop in Bow, NH just south of Concord and other New England locations. http://www.camerota.com/reman-units/transmissions
thanks I have seen the place in ny before but it is 6 hrs away, checking into camerota. Anyone know the spacing measurement between the flexplate and converter for a caterpillar 426b or similiar?
Don't quote me, not sure if there is such a spec/measurement. Just to clarify, my earlier post, If the spout is worn like that I am assuming the convertor is not truely centred with the driveline. So, if there is nothing obviously worn ie, cracks in flexplate or worn spigot & bore, you need to verify the spout trueness by mounting the convertor to the engine flywheel & measure the runout on the spout , while rotating the engine by hand. That will tell you if it is truely centred. Was the charge pump ever looked at/ replaced? I would imagine it would have been a casualty in the last repair? Some pictures of previous damage would have been helpful, we don't really know what you're dealing with.......
Got back to the backhoe today and though I suspected it was worn drive tangs on the converter like last time low and behold they were fine. However the converter is rubbing on the transmission pump bolts the two bolts on the top of the transmission pump have half the heads worn off. The converter also rattles when I shake it, is that normal? there is movement on the interior spline which is where the rattle comes from. This does not explain however the metal in the transmission fluid. I removed the fly wheel and it is rugged. No wonder its $1400 for a new one. No crack or where and when I drop the converter hub into the flywheel it mates perfect no room for movement. If the rebuilt converter isnt the cause I think I will have to open it up and look for clutch and bearing failure. Any adivce/suggestions?
If the converter is rubbing the pump bolts.That would indicate possibly to much end play on the crankshaft! That would also push the input drum in the trans back,and may cause the input drum washer or bearing to fail.causing the metal.You should check crank end play. ------And the rattle in the converter--Should be a dull rattle,more like a thump.If it sounds like someone dumped a can of nuts and bolts in there,you got trouble.
No measurable crankshaft endplay. less then .001 inch which is well under tolerances from caterpillar. Cat gave me an estimate of $4315 for removal and bearing and reseal on the transmission. Of course it would be less because I have the trans out already and would reinstall myself. The input shaft will not turn by hand but rear output shaft turns freely, anyone know if that should be the case? still looking for a affordable rebuilder. thanks.
The converter charge pressure should keep the converter forward and away from the pump bolts. I am suspicious of the converter being the right one. If the pump is still intact it should hold the converter in place due to the length of the drive sleeve and tangs. The sleeve is either too short or the pump is worn badly allowing the converter to rub the pump. Later Bob
Does your trans have two splined shafts coming out of the front?If so one of them should not turn,that is the stator support for the converter,the smaller one should turn with some effort by hand or at least with some channel lock pliers.Does your converter bolt to the flywheel,or does it float, driven by large splines.If the crank end play is ok,the problem is right there in the bell housing,as Bob said maybe wrong parts installed.------OBTW .001 end play does not sound right, .010 would be a better number.
mattm - Your first post says "the drive hub just failed" - sounding like the machine has failed to drive due to a lack of transmission pressure. What is the problem/symptom you have at present? Was the rebuilt convertor from CAT? Exchanged somewhere else? or was the original rebuilt - CAT or other repairer? The convertor position is fixed, the only movement being crankshaft endfloat. Unless the endfloat was excessive it should not have any effect on the problem. Where the flexplate bolts to the convertor, there is usually a smaller plate that would go between the circle of bolts & the flexplate. Assuming it is loose & not welded to the flexplate, is it in the correct position? The pump body is fixed, it's position controlled by the bellhousing mounting flanges. Does the pump have the correct mounting gasket/ seal ? Apart from these issues - as far as I can figure, the convertor is wrong & it's body is too big for the area it has to live/work in. But again, what is the issue for this repair - not driving? or noise?
Before I took it apart I guessed it was the same component failure as the last time which was the drive tangs on the TC. It is apart because it had 0 transmission pressure and machine would not move. it has been acting up losing drivetrain power, shift to neutral for minute and then back to normal since the TC and trans pump were replaced 400 hrs ago. I think it might be a bad TC. It was a rebuild from joseph industries. Inspection of the TC yields nothing so far other then some poor quality welds on it but if it is slightly out of round I have no way of checking it. Airman the small spacer plate is in the right position. Turning the TC by hand when it is seated in the trans pump it strikes the pump bolts on one side as it goes around. I am thinking either the pump which appears aligned properly is bad or the TC is.
It is not unusual for a converter to hit the pump when pushed in and turned by hand.In a proper installation,the converter is pulled out about .125 from bottoming out in trans.In your case it seems that ether the converter is two thick,this can be caused from "ballooning" from two much charge pressure.Or from the wrong part being to thick.This will push against the main pump gear and wear into the face of the stator,making metal,and full blown pump failure.At this point you need to pull the pump,open it up,and take a look.Then call Joseph and get the total height dimension,for that converter and measure it!
When you install the trans, make sure the converter will move in and out slightly before you bolt it up. This other problem sounds like the wiring to the neutral buttons on the hyd and shift levers. I assume your trans is syncromesh with for and rev powershift. The newer full powershift with controller in the lever had controller problems that would sometimes work and sometimes not work including not cranking to start. Later Bob