Jd 8630 Transmission Issue

[Krhaff13]

Okay I am officially stumped and looking for any advice. We had a reverse gear fuse onto the top assembly on an 8630. The tractor would go forward in several gears but would stall itself out in a reverse gear. We pulled the top assembly and replaced the shaft, reverse gear, clutch pack and synchronizer. After reassembly she ran beautiful for 30 minutes pulled just a 26 set of sweeps. As soon as I used a reverse gear, it locked up again. Im looking for any advise as it seems to be possibly a lube problem. Is it possible the transmission pump under rocker shaft is not supplying lube to shaft? The funnel coming from top of transmission cover seems to be dumping lube onto the assembly fine.

Any help would be greatly appreciated.
Kris

 

[tim s]

Did you inspect the lube pump when it was out? I does sound like a lack of lube issue..

 

[Krhaff13]

(quoted from post at 05:42:28 10/26/20) Did you inspect the lube pump when it was out? I does sound like a lack of lube issue..

Hey Tim! I was hoping you would see this after reading some of the posts you respond in. So when we had everything split and open I did not pull the lube pump. I did see just from the outside that it was the newer style pump. I confirmed with my uncle that he had it replaced about 5 years ago when they did work on the lower assembly. With that being said.....everything the large jd mechanic shop worked on 5 years ago has failed one way or another. I just dont know what else could cause that reverse gear to weld onto the shaft like that.

 

[wore out]

(quoted from post at 02:12:44 10/26/20) Okay I am officially stumped and looking for any advice. We had a reverse gear fuse onto the top assembly on an 8630. The tractor would go forward in several gears but would stall itself out in a reverse gear. We pulled the top assembly and replaced the shaft, reverse gear, clutch pack and synchronizer. After reassembly she ran beautiful for 30 minutes pulled just a 26 set of sweeps. As soon as I used a reverse gear, it locked up again. Im looking for any advise as it seems to be possibly a lube problem. Is it possible the transmission pump under rocker shaft is not supplying lube to shaft? The funnel coming from top of transmission cover seems to be dumping lube onto the assembly fine.

Any help would be greatly appreciated.
Kris

A couple of comments... since it locks up in reverse but drives in forward it would seem one of the forward "pinions" is what has seized to the shaft???

Transmission lube is a combination of leftover oil from the clutch pump that is not needed for the main clutch, planetary 2-speed, or PTO clutch and brake and the transmission pump.

Does it have a transmission lube pressure gauge, IIRC that indicates the lube pressure supplied by the clutch pump circuit.

Transmission oil pump flow is in addition to that flow.

 

[Krhaff13]

It does not have a pressure gauge for that. The gear that keeps seizing onto to the shaft is closest to rear nearest the back pump. I guess I believed it to be reverse but I think you are right, reverse is ahead of neutral likely near front of tractor

 

[rockcreek4630]

First you need to check lube pressure.
Those had different gears through the years
and you had to watch that you get the write
ones (if you change a bottom gear you might
have to replace counter shaft and top shaft
gear)

 

[Krhaff13]

(quoted from post at 13:11:40 10/26/20) First you need to check lube pressure.
Those had different gears through the years
and you had to watch that you get the write
ones (if you change a bottom gear you might
have to replace counter shaft and top shaft
gear)

So I have pulled the transmission cover which has the line with what looks like a funnel dropping lube on top of the shaft up. I could see lube flowing onto the top of the top assembly. Do you know if that is suppose to be at a certain psi? I will have to pull the rockshaft housing again to check that transmission pump flow

 

[wore out]

"what looks like a funnel dropping lube on top of the shaft"

There's a lot more to it than that. As I recall the shaft is drilled down the center with lube holes at each of the "pinions", I'm gonna GUESS that's the lube oil flow you are missing.

I had intended to grab the shop manual today and bring it home with me to post a diagram of the transmission lube oil flow, but my real job and old age/getting tired got in the way. I've been hoping GURU TimS would come forward and explain the intimate and unusual details of the transmission lube system.

What is the serial number, Deere retrofitted transmission lube pressure gauges to a range of serial numbers. I have a 20 or 30 page DEERE bulletin that lists factory updates to these tractors, I need to remember to look and see what is mentioned about the transmission lube pressure gauge vs. serial number.

 

[Krhaff13]

(quoted from post at 20:07:10 10/26/20) "what looks like a funnel dropping lube on top of the shaft"

There's a lot more to it than that. As I recall the shaft is drilled down the center with lube holes at each of the "pinions", I'm gonna GUESS that's the lube oil flow you are missing.

I had intended to grab the shop manual today and bring it home with me to post a diagram of the transmission lube oil flow, but my real job and old age/getting tired got in the way. I've been hoping GURU TimS would come forward and explain the intimate and unusual details of the transmission lube system.

What is the serial number, Deere retrofitted transmission lube pressure gauges to a range of serial numbers. I have a 20 or 30 page DEERE bulletin that lists factory updates to these tractors, I need to remember to look and see what is mentioned about the transmission lube pressure gauge vs. serial number.

I will grab the serial number tomorrow. I know its an earlier series as it has the 92 mm axel shafts. I believe you are correct about the shaft being drilled through and that lube is pushed through the shaft from that rear transmission pump

 

[tim s]

Call me after bit and we will talk about what is going on..740-743-1085

 

[Krhaff13]

(quoted from post at 04:05:55 10/27/20) Call me after bit and we will talk about what is going on..740-743-1085

Model 8630-SG
Serial #3-089854R

Tim, I tried calling a bit ago. I will try again in awhile.