Deere 4020 PS all reverse and 5th, 8th gear noise

fdt860

Well-known Member
I have a new to me 1969 4020 PS. Got it non running.
Now I have the engine running. The transmission makes an awful sound in all reverse and in 5th, 8th forward. Like if some bearing were out. Otherwise works very good.

Any ideas? Thank you!
 
Well, it's going to get expensive!

Never been into one but we had a
bad one at the shop ages ago.
Repair estimate was six grand. The
owner wasn't willing to invest that
much so it just sat there.
 
(quoted from post at 11:05:08 04/30/23) Well, it's going to get expensive!

Never been into one but we had a
bad one at the shop ages ago.
Repair estimate was six grand. The
owner wasn't willing to invest that
much so it just sat there.

Well, my labor is free. I hope only some needle bearings are going bad, or the 2 bearings in the overspeed assembly are dead. That would make sense? It shifts too nicely to be completely dead. I hope $1000 in parts and couple nights without sleep fix it.

One more thing I noticed: In any of the gear, it will make the same awful noise if you depress the clutch. This would mean C1 or C2 shaft bearing's gone, right?
 
C1 and C2 clutches are engaged in all forward and reverse gears in some combination. The common element in all reverses is the B3 brake. 5th and 8th forward engage B4 brake, but this brake should also be engaged in 6th as well. Do you have issues in 6th?
Does the PTO engage and disengage correctly?


Do you have the service manual that covers this tractor? You will need the manual and several gauges, hoses and fittings to run a series of pressures tests on the entire system. Do all of the tests before splitting the tractor.

Oil is full, correct? Have the hydraulic/transmission filters been changed since you got the tractor running? Has the sump screen been checked?
 
Yes, I have all the manuals. 6th works great. Pto turns on and off, oil is clean.

I believe issue is not in the hydraulic system,and I need to find which part turns against which one in each gear.
The noise is very loud in reverse,meaning that the relative speed in reverse is much higher.
 
Yes, I have all the manuals. 6th works great. Pto turns on and off, oil is clean.

I believe issue is not in the hydraulic system,and I need to find which part turns against which one in each gear.
The noise is very loud in reverse,meaning that the relative speed in reverse is much higher.
 
Looking more at the chart, I think my problem is in the planetary carrier.
"Silent" gears, all involve the C3 clutch to be engaged. C3 is locking all motion in the planetary carrier.
I will see what I found upon teardown. I compared the numbers on JDParts, and it looks like if the problem is on the front side, I have all the powershift from a Deere 500C backhoe (all gears and shaft are the same). The 500C powershift was very good except C3
not working. I did not fix it because it was clearly a part tractor. (no backhoe, loader mounts were not tight on the engine, all leaky hose or ready to blow up, etc...)

There is however a difference in the other set of gears, that I cannot quite figure out (one planet is still the same PN between 4020 and 500C , but the 2 others planets are different). I also have a used 4430 rear pack that was also in good working order. Tractor was parted out because the differential quill bearing had failed, and tractor was run that way for many hours, filling all the system with bad stuff.
 
Let us know what you find. I am still wondering how 6th gear is not making noise. C3 locking the planetary would certainly narrow down the where noise is coming from, and I agree that the planetary is most likely. However, C3 is not engaged in 6th. Just a guess on my part, but I am thinking that B3 and B4 are possibilities for the problem area. Still does not explain 6th as B4 is engaged in that gear.

A bit of a thought here, when shifting into 5th and 8th B4 has to engage during the shift as C3 disengages. In 6th, B4 is already engaged when the shift occurs, if shifting each gear in sequence. Does it make any difference if you skip a gear shifting, like 4th to 6th or 6th to 8th? Only a theory, but this would be way to check if the noise occurs specific to the C3 disengage/B4 engage (4th to 6th) and keeping B4 engaged (6th to 8th).
 
I'll second what Big 86 said with checking pressures before tearing anything apart. Even if the hydraulic system part of the transmission is not part of your issue you'll still want to check for internal leakage. You'll probably find questionable parts inside when you get it apart and you'll wonder if some things are safe to reuse (trans pump, clutch drum sealing surfaces, etc). There could also be more than one issue that you don't know about or might not see it when you get inside.

As for the noise, I'd try doing the clutch drag test as explained in TM-1006 section 50 page 20-15 step 5. Strange why it's quiet in 6th but you're probably on the right track with the issue being in the C3/B4 area.
 
(quoted from post at 18:45:31 05/06/23) Let us know what you find. I am still wondering how 6th gear is not making noise. C3 locking the planetary would certainly narrow down the where noise is coming from, and I agree that the planetary is most likely. However, C3 is not engaged in 6th. Just a guess on my part, but I am thinking that B3 and B4 are possibilities for the problem area. Still does not explain 6th as B4 is engaged in that gear.

A bit of a thought here, when shifting into 5th and 8th B4 has to engage during the shift as C3 disengages. In 6th, B4 is already engaged when the shift occurs, if shifting each gear in sequence. Does it make any difference if you skip a gear shifting, like 4th to 6th or 6th to 8th? Only a theory, but this would be way to check if the noise occurs specific to the C3 disengage/B4 engage (4th to 6th) and keeping B4 engaged (6th to 8th).

I retried the tractor, and there is definitively also some noise in 6th,close to normal but not quite. I amguessing that the planetary turns very slowly in 6th.

Thanks for the advices,I will let you know. I got another 4020 I need to finish before this one get fixed.
 

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