Hi all I have a 980c and just finished rebuilding half the engine and changed all the pumps, " hydrolick, tramsmition and steering" now the engine is grate the hdrolicks very good, but unfortunatly no moovment. When gear in 1st mooves a little, less in 2nd and no movment in 3rd and 4th gear at all. I was hoping that when the new transmition pump was installed that it would have solved the problem.... but with no luck. For the record the previous pump configuration was so ckokemani that the transmition and transmition were drawing off the same pump with hoses butcherd to do the job and had another pump for steering, both pumps where off some kind of grader or diffirent size machine. I have three new pumps instaled now and overcomed that problem. What do you experts out there think could be the problem and how to best solve it..??? should I change the transmition?? rebuild it?? or do something else?? ointhead
Are you sure the tranny pump was rebuilt correctly? I had this problem with a crane they did something wrong with the pump and it wouldn't shift. I had to pull it out have it rebuilt again and reinstall it. Are you sure the tranny pump was rebuilt correctly? I had this problem with a crane they did something wrong with the pump and it wouldn't shift. I had to pull it out have it rebuilt again and reinstall it.
I put in a new Hydrolick and transmition pump and a whole new set of hoses and clamps. The tranny pump is connected to the back of the main hydrolick pump and is connected with a tork.
Do you have correct pressures to the transmission valve and converter? Pump pressure should be 300psi at idle. Converter inlet maximum 140psi at high idle/cold oil Converter outlet 55psi at high idle/stall condition Sounds like your converter might be the problem, either it isn't getting any oil or it is worn and need to be rebuilt but check the pressures and go from there.
Thanks for the pointer... the last thing I want to do now is blow up the engine and connectins around it to get to the transmition and overhaule it... so your sugestion to gage the psi is good advice. Now I have to get a preasure tester.
If you need a parts manual or servicemanual for a good price try this site, they have good stuff. http://sudoremont.com.ua/english/katalog/caterpillar/cat-24.htm
Wow grate site..... thanks seems I might buy all my manuals from there hope they give quantity discounts,,,
Just thinking outside the box a little... You may want to check your braking system. From memory, the left brake valve also neutralizes the transmission by supplying air to the transmission control valve. The brake control valves can seize in the part-on position when they get dirt from the cab floor stuck in them.
Damn that Box.... sure does get us confused.. Well that was a grate sugestion I hope it solves the problem. sure does beat having to change or overhaule the trans. Thanks a lot
I really hope it solves it as well, but don't get your hopes up too much. It was only a suggestion!
We've been so swamped here lately that I overlooked this message until now. I hope you've solved your problem by now, but if not, we always recommend first checking screens and filters. If clean, then begin troubleshooting starting with pressure test. We would be happy to help you further with this process over the phone and could provide all the data you'd need to do so.
Well it did not hurt to check but no luck:cool2 We went through all the possible simple fixes but no luck. The only thing that might be worth looking at is that we hav just recently redone the whole hydrolick pump system including the trans. pump which previously was conected to the steering or the implement pumps, both were the wrong ones causing oil mixing, and just put in to go through the auction... So now that we have scrped both the old pumps and bought three new pumps.... one infront of the fly wheel "Implement" and one on the back of the fly wheel "transmition" with a third pump on the back of that "steering" with a shaft rod connected to it. All the pumps had new hose connections and we did our best to put in the hoses.. we had to close a connetion or two of the small over flow ones because we could not figure out where it went.... The engine was just half rbuilt and has grate grunt and the trans engages in 1st moves a litlle and barely moves in 2nd, and does not move at all in 3rd and 4th... So I hope that made it a bit clear...
How did the screen/filters look? If they are clean a pressure check is imperative.
They were clean and good. We are tryingfor the presure test, but all the shops around dont have any preasure testing instruments??? what can we do now? how much would one cost? and could I order one over the net? We got the hoses connected to the right place and got very little improvement. No matter ho much you rev the engine it doese not pick up speed.
You can order a PSI guage and test line through CAT.
We can supply everything you'd need including hoses, gauges and instructions. PM me if interested.
Maybe when hoses were disconnected dirt got into the transmission control valves and plugged load piston orifice. From the original post it sounds like the machine tries to move a little in first gear, they will do that if they only have initial pressure. Be careful testing, initial pressure can smoke clutch friction discs if you have it in gear too long, especially at high rpms. I have witnessed this problem twice on 980c's. I agree you need pressure tests. I have gotten them to move by back flushing the load piston orifice by hooking my gage hose from P1 to LP port and starting and putting it in gear. Just a suggestion. Check pressures. Good luck.
Bolt thrower is right, could be dirt in the orifice, but there are a number of other possibilities as well. Best to record P1,P2,P3 pressures in all four speeds, both directions and hopefully this will help to isolate the problem area. We don’t allow our mechanics to start tearing things apart until they have done their homework- seen too many guys spend countless frustrating hours chasing ghosts. True enough about initial pressures but really no reason to run it more than a few seconds in each speed.
Thanks that sounds reasonable... I will give it a try. We found that the accelerator doese not reve the engine enough and had to recalibrate the diesel pump... Now we have acheaved higher reves and the machine runs in 1st, 2nd, and 3rd gears but when you shift to 4th it starts to decelerate...
Getting closer, if it picks up with more RPM that indicates torque converter or pump but I would still do the pressure test. Can’t understand why it would “decelerate” in higher speeds unless one of the lower speed clutches is smoked and warped causing it to stay mechanically engaged when it shouldn’t. If that were the case you should have black rubber in the screen.
980 c transmission dumping fluid hi sorry for posting here but i just registered.my problem is i dumping transmission fluid its filling up the hydraulic tank.ive had problems on another one of our loaders where the tranny was filling with hydraulic oil.i changed the pump and it stopped.now i have tranny fluid filling my hydraulic tank i was wondering if it also could be the pump. has anyone run in to this problem before.thank you
No problem Mate, We had the same problem and realised as I have mentioned above that the hydrolick pumps were and hose connectiones were all wrong. You have to make sure that you got the right pumps and then get it connected to the right spots and take it from there. At the moment we just finished putting in 6 new cilinders and shaved the head ant put it on only to find that the radiator is not in tip top condition, after that is solved we hope that things will pick up
Ragtop, whats machine do you have?
sorry its a 980 c.well today i changed the tranny pump seal again i put it in backwards and that stopped the hydraulic tank from overfilling .but the tranny is filling up now ordered a new pump today ill try that
Have you had the loader for some time now or have you bought it recently? If you had it for some time, how was it doing before this problem? Did you notice any drop in trany power or implement operation?
The transmission pump and hydraulic pumps all run off the torque housing. They each have lip seals designed to keep the oils separate and should be the source of your trouble. Since the oil is going from trans to Hydraulic my suspicion would be towards the hydraulic side.
tranny pump hi i changed the seals.when i put the tranny pump seal in backwards it stopped the hydrauli tank from overfilling.but now the tranny is filling up when i get a chance ill try the hydraulic pump seal again.we have 3 980c i had this problem on another one and the seal solved the problem.ill try the hydraulic pump and let you know how i made out thank you
There is a small plastic orifice type screen in the control valves that when it played up it would upset the drive quite a bit, control valves have to come out (not pretty) and i think it is about 2 stacks down from the top plate in the valves.
Good tip Gavin! We have also dealt with problems associated with that damned orifice. :Banghead It is located on the bottom of the main pressure control valve and we’ve seen them clogged, cracked, and even melted over the years. My only disagreement would be that it is common to all speeds and would not isolate only fourth as described by CAT D8 N.
My mchanic called me today and said all is well now.... so lets hope it says like that,,,, I will be visiting him soon and see what the go is
Congrats! Let us know what the problem was!
Thanks a lot.... Well it was a group of problems but it boiled down to not enough grunt in the engine.. Had to chage the six ngine cylenders sleves and do a semi overhaul , cleaned out the radiator, cleaned all the filters, fix the diesel pump twice, adjusting the diesel injector to rev up the engne, and pray to God it works out... boy Hamdulilah big time... Thanks for very that helped out... apreciate it guys...:usa:drinkup
Thats the one, surprising what headaches it can cause, not pretty on a 980C to get at either.
thanks jusy an update well i changed the 2 seals in the hydraulic pump and that stopped my problems thanks for your help