cat 621B trans problem

[HATCHEQUIP]

Outfit brought in a trans for a 621B said it started slipping and they had found debris in the strainers "didn't get to see what it was" and could we see what was wrong "yes would have been nice to do a little checking in the machine". Pulled unit down and could find nothing wrong, disks, pumps, bearings all looked and measured good, went thru valves and governor and could find nothing wrong. replaced all seals and they picked her back up. They got her back running and called today that its still slipping but now Ive got more info on what its doing and im hoping to get time in the next few days to go do some pressure checks. What they say its doing is it pulls fine in first but slips in the rest of the gears if they get it above 1/2 throttle even in reverse "completely stops pulling in every thing but 1st he says" asked if the hyd.s still worked while it was slipping and he said yes. Any one ever run into something like this.

 

[rdr]

did they replace the oli cooler and clean all ???? the cooler lines when they replaced the trans.

 

[HATCHEQUIP]

No the debris they found could have come from a past failure but this time around didn't find anything wrong with the trans or torque

 

[rdr]

No the debris they found could have come from a past failure but this time around didn't find anything wrong with the trans or torque

well been there if non cat rebuild ??? value body get the books. call cat with all nu. on case . and valve body. then check assambely perbook .next all passeways.the mix and match of some rebuilders can be a very exp. way to fix older eq.thats y we keep and rebuild all our own eq. we use cat alot but in our shop . in the end rebulding your mechine may look expesie . you know what you have. and go to work when you need to .

 

[HATCHEQUIP]

????

 

[catken]

I'd check pressures-Did they clean - flush all the lines? Should tell you alot.

 

[jjimbo]

Check the drive clutch on rear of engine

 

[d9gdon]

I'd check and adjust the shifter linkage.

 

[HATCHEQUIP]

Thanks guys havent had allot of time with it had to go to florence Al and work on crane but I was able to check the main pres at filter housing and it was good at all times did pull the cover and check the linkages for the shifter and spools being flush and thes were awfull close I think the 1st step I gave a 1/2 turn and the second step gor a 1/2 turn and the 3rd step was dead on. pulled the cover on the rear of trans to look at the end of the drive shaft and it was still turning the same. Hope to get out there in a few days and hook up gauges at the other ports but now its raining and the forcast is for more rain, ice and snow "they dont know" If you can think of anything else please post.

 

[Bob/Ont]

Pull the axles and run a good pressure test.
Later Bob

 

[d9gdon]

Make sure the cab is not loose and causing linkage movement. Just trying to think of the simple stuff first, I had a straight 627 that this was happening on.

 

[d9gdon]

What's the update Hatch?

 

[Mjrdude1]

Listen to Jjimbo, he is most likely correct. In the bell housing there is a clutch with a large Bellville spring, it is most likely junk and slipping, and I bet it also slips in 1st if it gets into a hard enuf pull. Bitch to fix but can be done onsite.

 

[HATCHEQUIP]

Nothing yet with the snow and rain the pans are setting as the job site is rotten. Dont think its the clutch as the shaft is still spinning if you pull the cover and take a peek at it where the snap ring holds it in.
Instead its been making trips over to Florance AL.

 

[jjimbo]

On your 621B the drive shaft will turn until under load unless the clutch is completely out if springs are week will still grab. try crowding the ejector forward or back and can up. see if it starts to slip