I have a 621 cat scraper with a slipping transmission. It pulls fine in all gears until in is used for an hour or two, then the transmission gets hot and if it is shifted will only engage in first and reverse gears. After it is shut off and cools (overnight) it pulls fine until it again gets hot. I have changed the transmission fluid and filter, oil and filter looked good. I think the transmission is over heating, does anyone know how the transmission is cooled and what I need to do to fix it?
Hi Travis D, What is your serial no/model B,E,F,G,H,K, etc Also could you supply more info please do you lose hydraulic function as well ? What is your engine speed doing when it starts slipping? Does it have a hydraulic retarder? Noises ? Vibrations? Does it have the hydraulic seat? how do you know its slipping? Does it try to change out of first or is it stuck in this gear? Are you going by gage for overheat or just a guess? Mark
I am new to most of the heavy equipment so not sure about hydraulic retarder, and hydraulic seat. no noises or vibrations. It will pull and shift in all gears for a while. It will pull in 2nd gear for a couple of hours maybe longer, not enough power to load in higher gears, after a time the trans get too hot to touch (no gauge) and if it is shifted it will only engage in reverse or 1st. Have used it for several days off and on and doesn't seem to be getting worse. The only markings on it are 621 (no suffix), I will try to find the serial no. thanks
Torque converter?
The trans will likely need to be rebuilt so don't run it any longer if the filters are clean as you say. You need to hire someone familiar with them to pressure test it and find the exact location of the oil leak. Testing is a bit involved, need many gauges and a tach on engine, both axles pulled out so it doesn't move while testing. Later Bob
if you want a transmission for a 621 let me know and i will make you a killer deal on one thanks quinton 800-404-2488
did you pull the two screens and magnets at rear of transmission near the bottom of the case (four bolts in each cover) if you have a 500psi gauge plug it into the top of the filter housing (9/16 un oring thread) and run machine if screens clear. there is also a screen in the bottom of the flywheel housing you should check if the machine has a retarder it will have a lever on the right hand side of the steering column the reason I ask about the seat is that on the B series machines there is an option of a hydraulic seat and its oil supply is taken off the transmission filter housing if the transmission pressure gets low the seat either wont raise or only part way Mark
wow thanks, I haven't been able to get to the machine to check the numbers but it does not have the retarder or hydraulic seat. I will check it this weekend and get back with you all. again thanks for all the ideas.
I couldn't find any numbers other than this on the transmission. If that's not the right thing do you know where I can find it?IMG_3807.JPG.jpeg
Hi Travis Everybody meant the serial number of the machine. If its a 621B the serial number will be something like this : 45P2727. The first 3 is called the prefix which identifies the type/model.
If it's a straight "621" model designation USA built it's a series 23Hxxxx with power shift. My info shows a change at s/n 23H4299-up to 8 speed semi-auto transmission.
I'm trying to attach a pic of the trans tag. Not sure how to do it. if it didn't work the tag reads. Group # 3s150 Test # 6481 Arrangement # 5s7778 converter # 31t3933 If these #s don't help does any one know where I might find the correct ones??
That transmission Test # corresponds to a 621 of 23H S/N prefix somewhere in the range upwards of 23H3785, probably substantially higher and may well fall into the group of machines with S/N higher than 23H4299 as mentioned by OM in his post #11 above.
We still don't know if it's a 621. The serial number tag should have been on the rear of the diff housing on the drivers side. The rivets should still be there if the tag is torn off. Look for numbers stamped into the housing, may have to scratch the paint. They could have transplanted the transmission or the tractor itself from a 623. I show it to be from a 623 SN 52U 324-Up Both of them used the same trans and converter so you wouldn't have any problem using this information for any parts needed.
the ID plate should be on the chassis underneath the cab if the plate is missing the numbers should be stamped into the chassis as well Mark