I'm doing the pressure test procedure at the FNR valve on top of the trans. The first test indicated my pump supply pressure is low, and i need to inspect the pressure regulator. My symptoms are slow to engage in forward and reverse. Its far worse when cold, and even when its at operating temp, its still slow to engage. I think the pressure test is sequential. Meaning, if the first test at port M1 is a fail, the reason for failing has to be addressed before continuing to the next test. I still performed the full test procedure, but I dont think I can use the info. I did find an odd result when testing the control pressure at port M2. When in N, there is no pressure. in F and R, the expected pressure should be 160 psi at idle, and 189 psi full throttle. What I get is 25 psi. When I increase the throttle, it slowly creeps, and then moves up to 140 psi. I am only explaining what the test result is in case someone might know what the cause of that might be. It just seemed odd I suppose. So for the actual questions I have, Where is the regulator located, in the control valve, or the transmission pump? Does anyone have some experience with why my carraro is slow to engage? I have new filter and fluid, and all of the screens all clean. I am slightly overfilled by about a quart or maybe 2, if that makes any difference. Thanks a bunch!
Ok after a bit of digging I have found some things you should check. I believe that since your pump seems capable of making around 140 psi. I don’t really think it is the problem. I have seen worn pumps and they usually are not even capable of 100psi. I believe the next logical step would be inspecting each valve in order after the pump. Obviously the main safety valve would be impossible due to it being part of the pump itself. Here is a hydraulic schematic and a pic from the parts book. I think you should look at part 12 and 13. The divider and modulation valve. There is also a valve at the filter if you have 4x4 that may need to be addressed.
This is GREAT news. Its also the #1 best reason to join a forum like this. You can't possibly know how much I appreciate the fact that you looked into this issue. Shocked and amazed, and very appreciated! Thank you! I have the 1,468 page PDF manual, and for some reason Im not finding that same picture of the "transmission hydraulic system". Whatever the parts book is, I dont have the same info, so i have been trying to put this in order so I understand better. Are we talking about item 12 and 13 from the hydraulic system picture, or do you mean the FNR valve on top the transmission? Or are the valves part of the FNR control valve on top the trans? Sorry for being daft, I just cant get my mind to wrap around this one! My 580 SL is the 2wd version, fyi
No I meant 12 and 13 from the exploded parts view. I got this info from the actual transmission manufacturer, Carraro. Your transmission, I’m pretty sure, is a TLB1. I was just looking at the info page I attached to earlier that is supposed to go with the hydraulic schematic and it seems some of the numbers don’t jive with the descriptions they call out. For example 12 and 13 on the schematic are the forward and reverse clutch. But I hope you can see by the following the flow of oil that there are several places to check for leakage before condemning the transmission pump and being forced to remove it from the machine. Here is a link to a YouTube video on the valve body.
The Cararro tlb1's were used in several different models of 580's. The transmission repair details are covered in section 6002 of the service manual for your 580SL. Which series is your tractor ? Here is a thread with a similar problem as yours. Maybe. -----> HeavyEquipmentForums
Its a series one, if they actually call it that. I know for sure its not the series 2. Thank you for the replies, I still cannot get over how helpful members on this forum are. Maybe ive spent too much time in cruddy forums i suppose.
Thats a great video, a perfect step by step for tear down and reassemble even a grade schooler can follow. Nice find!
Acecadet you nailed it. There are these 3 springs that nest like those wooden Russian dolls, if you know what I mean, one inside the other. All 3 broke. Does anyone have a copy of the parts manual, that might be interested in a 580sl service manual?
Here is a link to the CNH online parts book. Select the one you need. https://www.mycnhistore.com/us/en/casece/light-equipment/loader-backhoes/sl/cn/NA_E_S_49_LOA_032_SL
That is great news. Looks like they only sell the springs in a kit. Post back when you get that machine back up and running. Glad I could help.
First off, before I get completely flamed for what I did, understand I am not saying this is a long term fix for the problem. I understand about the stresses the springs endure, and how adding heat is just giving the spring a soft spot to fail again, and there are important factors like spring tension and height, not to mention if the wrong spring types are used, will that possibly damage the transmission, and many other reasons to not do this, my mind still went "hmm. I wonder..." So the big spring twists into itself nice and tight. I added a spot weld to keep it from untwisting, but now its shorter, and the tension is different. The other 2 springs were broken and only a portion remained. I used the lathe to build a stepped insert for the stack to sit on, which raised each spring to the height they would have been if not broken. and it worked great. I will be replacing them of course, I just wanted to find out if it was even possible.
Desperate times call for desperate measures. It’s your machine you can do as you wish. I would not run it for long like that. It could cause internal damage to seals and clutch packs. I’m glad you were able to prove that was all that was wrong.
Agreed. The only use since doing the spring thing has been to verify it went into forward and reverse. It does, so thats enough relief for me to know the trans isnt smoked. The real parts are on order...