When in gear, once in a while and now more often, itacts as if it jumps out of gear or like you push in a clutch. Shift to neutral once or twice and it acts normal again. Happens in first and second gear, don't really know about third. When in gear and working normal all is normal without slip or anything wrong. Any suggestions?
Does it just happen when shifting from forward to reverse and vice versa? Ours was doing that and the presure was good while in gear but it sometimes wouldn't go into gear shifing from forward to reverse. Cat has a neutral safety plunger in the transmission so if you start the loader in gear it will not take off. Once it's shifted onto neutral it then goes into gear. Our plunger must have been triggered during low pressure while shifting and had to be shifted into neutral to get the machine to move. I figured out where the plunger was and installed a weaker spring and it works great now. Not a CAT approved repair LOL but it works. Randy
What generation 988 do you have (i.e. 988A, 988B, F, G, or H)? I experienced a similar symptom when I first got my CAT IT18F, I would shift into reverse and sometimes it would do nothing, and sometimes it would go into reverse and suddenly lose power to the transmission (but the backup beeper kept on going). The solution was just to make sure the shift lever is pushed firmly all the way into reverse and it now always works when I shift it firmly. If your 988 has an electrically controlled transmission, it could be a dirty or loose contact or switch that is shifting it into neutral. What I can say with near certainty that your tranny seems to be shifting into neutral by itself, as you say it works fine when its working. Transmission pumps and torque converters don't die and return to life, and the symptoms you're describing sound like it's just going into neutral. Do you hear any unusual noises or notice any other odd behaviours from the machine?
Always check your screens and filters first. If clean, it sounds like the pressure is dropping below the safety valve setting which is usually in the 100psi range. This can be caused by many things but one of the most common can be that if the engine rpm drops too low between shifts or under load the pump of course slows down too and may not be keeping up enough volume to satisfy the neutralizer. Sometimes you can set your engine a little higher and solve the problem but beware that this could be an early sign of trouble….BETTER CHECK THOSE SCREENS! If you still have a problem we have many ideas but would need that serial number first and a detailed description of the symptoms. For example, does it do it in reverse too?
When this happens does the display stay in forward/reverse or does it drop back to neutral,cause i've come across this on a 980 with command control steering and when it happen the display went to neutral and the FNR switch was faulty
That little pesky orifice/screen could well be the culprit to Trevor. Just had a D11R & D10T with funny tranny drive issues, both machines had broken the woodriff key in the tranny pump and would sometimes grab the gear and turn it and other times it would not making the problem intermittent and a challenge to diagnose, sometimes you just wish they would break a big bit cos' then you are done with diagnosing.
It got worse last weekend and had to limp back to the shed. Lost most power and would barely move, was a little better in reverse. My mechanic is checking pressures and filters today. I hope it is the tranny pump only. Thanks for all your help so far.
Good luck cwooten ! Don't forget, we'd all still like to know the serial # or at least the model of your tractor.
We have a 980F that has the same symptoms. It works great in reverse, but it seems as though it slips out of Forward. When it slips out of gear, if you return the shifter to Nuetral, then slide it harder to Forward, it grabs. But then it'll slip again. Any Ideas on where to start. Maybe the linkage, or the Nuetral Fail safe switch? What is the FNR switch? Thank you in advance.
i have a 988b n there were the problem in shifting gear. i changed the gear oil it find it much better than previous. try this dude. it is really helpful
Always start by checking screens. If you can post some pictures of them we may be able to offer some advice.
What's your serial #? 988’s have been around for fifty years so I'd like to know what generation we are dealing with.
shift had the same problem with a 420 backhoe and 950 loader...it was the sensor/switch in the shift lever. 1200 bucks or so for an entire assembly. once we took the old one apart we were surprised at how small the contact points are. not much to wear before it fails. the part didnt even look worn.
THis turned out to be a bad suction hose. It collapsed at times so the pump couldn't get oil. Had to clean out all the control valves and put in a new pump. Runs great now.
Can anyone point out where those screens that you guys are talking about are located ? Thanks in advance.
You need an Operation & Maintenance Manual. For your 988B it's actually two documents, one for Operation, the other for Maintenance. Pretty well tells you all you need to know. Go to - https://catpublications.com/ When the popup appears click on "Continue as Guest" Type SEBU5669 in the box and click Search. You should see the illustration below. US$28 for a pdf download. The other document is reference SEBU5667.
Thanks Nige. The previous owner has those manuels and will get them to me as soon as he can. As I have just brought the machine back to the workshop for a washdown. I was hoping someone could point me to the location of the screens so I can check them once I get it washed down.
Does shifter feel sloppy usally they are hard to go into gear when it's worn ?