Hello! I replaced my clutches ib my jcb due to good reverse but no forward. After that, I lost all oil pressure and purchased a new pump, torque converter. It's a borg warner velvet shuttle T71 that I've dropped out of the machine twice. Once I replaced all that, I filled with tranny fluid and it moved very well forward and backward. I drove it for about 5 minutes down the driveway and it started to lose forward. Gone. Had to back up the driveway in reverse. Noticed that the transmission was hot to the touch. I have also replaced the sump filter in the pan so a clog is not the issue. My question is, if the transmission fluid is getting hot, would you lose forward but not reverse? It moves forward good from a cold start but then warms up and nothing. I even replaced the neutral safety switch to rule that out. I will be pulling out the tranny oil cooler in the am but just not convinced that the cooler is the whole problem. I have heard that these BW velvet shuttle trannys have another filter somewhere but where is beyond me. If anybody has any knowledge of these machines, any help would be greatly appreciated!!! I'm just at wits end and ready to take a sledge hammer to it.
Welcome to HEF @Dan518 ! That sounds like quit an ordeal you have going on there. Unfortunately there is not much that can be repaired on those velvet drive units, from the outside. You will need to pull it out again & check all your oil control rings, particularly the two small ones that fit on the end of the mainshaft & seal inside the planetary gearset. - these are very easily damaged during assembly. Did you use a service repair manual when this was repaired? Is it possible the seal on the forward piston was damaged during install? Did you measure the forward pack clearance during assembly? Is the spacer snap ring between the forward piston & bellville washer correct size? The more info you can give us the more we can help
Thank you for replying alrman! Yes, we did use a manual for a borg warner manual. Well, we never did one of those before and were very careful putting everything back in but don't think we checked clearances. We will pull it back out and will get answers later today. I'll keep you filled in and a huge thank you for the help!!!!!
Hmmm..... detail Dan, a good repair is all about the detail ......
Lol. You are completely right! Nah, I'm done with it. I'm going to order a remaned and throw that in. For me, it's worth it than to throw more money into something I know very very little about. Only thing, do you know of any other filter besides the oil pan filter on the shuttle? It would make sense if there's another filter I'm missing. Another thing. I got into a discussion with a guy that insists I can use regular hydro fluid in the tranny instead of dexron 3. I insist on using what was designed to go in it but this guy acts like he knows everything there is to know about everything.
RE the filter -From the factory there is no filter apart from the screen in the oil pan. (JCB & Case) It's possible someone has fitted extra filter to one of the cooling lines, so anything added should be easy to locate. Re the oil - I would agree in using the hyd oil or a 10W trans oil. When I worked for a dealer, there was the a large company that had a fleet of Case 586 forklifts which used these transmissions. We would regularly rebuild these for them while they ran on Dexron, we suggested they replace the dexron with 10W - They stopped sending the shuttles....
Aaahhhh. Gotcha. good to know. i'll buy 10w then. Thanks so much alrman!!!!
A little question for you Alrman. When we installed the new pump, we were not sure of the correct way to put it on. When we pulled off one of the hoses on the oil cooler, the oil just poured out like pouring milk out of a carton. We did this very quickly. We didn't let it pour for long. I'm wondering if it has too low of pressure from the pump from being installed wrong. That may account for the fluid overheating. It's not pumping through the cooler fast enough. I guess my question is, if the pump is installed wrong, would it still have enough pressure to move it in reverse well and very little in forward? Just shooting out thoughts before I spend 2400 dollars on a new one.
The pump ( I am assuming the charge pump on the front of the transmission) has a bolt pattern that will only allow it to be installed one way. When you pulled the oil cooler hose, the engine was running? They don't have much pressure maybe 20-30 psi..... to test the transmission pressure you need to install a 500psi test gauge into one of the test ports on the transmission housing - there are various ones depending what you want to test.
Ah ok. No, we did not have the engine running. Well, that's a lie. We had it running for about 5 seconds then shut it right down.
We found a hobbs pressure switch on top of the shuttle with no wires going to the 3 prongs. From what I understand, it controls pressure through the pump. Problem is, we know one wire goes to constant power and the other 2 is a big? Lol. I'm thinking that that may have something to do with it.
Ok. Found out the hobs switch is an aftermarket switch. I looked up a T71 Tranny pressure switch for a jcb and it only has 2 connectors on it. When I get my new tranny, I'm not sure where those 2 wires would come from? That switch had no wires going to it so I'm not even sure if it makes much difference but it should. I don't know, ready to set the damn thing on fire.
Hi could anyone provide me with some ionformation on transmission removal on a 1988 JCB 1400b. I need to replace the clutch packs as forwards has tons of power but forward seems to slip going up hill. Thank you for the help!!!!