4020 trans problems

[Anonymous-0]

I was just wanting some input on what some of you guys would take to be wrong with a 4020 that is stated like this in an ad- Tractor does have problems shifting in 6th & 8th gears, goes in gear but grinds. All other gears shift and drive good with no unusual noise. Any input on this would be appreciated. Thanks.

 

[Tim in Montana]

I'm not an expert on this subject by any means, but it sounds like the synchronizers are worn. I have just had problems with the transmission in my 4320. Not being able to get the transmission into 3rd gear. I still don't know for sure what the problem is because of the inclimate weather we're having at the present time.

 

[Anonymous-0]

The gears shifted (actually cogged clutches with synchronizers, no sliding gears) 6 to 8 are exactly the same as 1 to 3, 2 to 5, and 4 to 7. They may be spinning faster going 6 to 8 though.

Gerald J.

 

[RobMD]

synchs. what a job to get to, in my opinion.

 

[Tx Jim]

4020 looker,If it will shift in all gears but 6 & 8 correctly then I think its a shift linkage or adjustment problem. Possibly lose quadrant on dash. Tx Jim

 

[Anonymous-0]

Don't have experiences with a lot of 'em but with one in particular I sure do!

As Gerald J says, the "things grinding" in 6 and 8 are THE SAME PIECES that are at work when you shift from 1-3 or from 2-5 or from 4-7.

The synchro range transmission has a top & bottom shaft. Shifting of the "bottom shaft" gives you the speed RANGES (1/3/R1, 2/5/R2, 4/7 and 6/8) as well as "neutral" setting needed when you have to tow it. You're shifting this bottom shaft when the shifter lever is moved forward & back while to the left side of the shifter assembly. The top shaft gives you the high speed, the low speed and the reverse in each of the ranges selected by the bottom shaft once you slide the shifter lever to the right.

The synchro range is a constant mesh type transmission. Generally grinding from gear to gear while shifting within a range is a warning of "future events".

I was running one with a 15' field cultivator behind & shifted from 3 to 5 having just "adjusted" some ground hog's front lawns in bean stubble, let out the clutch and throttled back up and it locked up so solidly and quickly the fan squealed in the belts and my knees hit the dash! No way possible to have again stepped on the clutch that fast. Had to CARRY it to the shop.

Split it open, put in new synchronizers, couple bearings, clutch, adjusted bearings, made cam plate adjustments and replaced a number of other associated parts. Pressed the wallet a good bit thinner & it now works great. My opinion.... not a time or place to cheap out & just do part of the job. Fix it all & it will serve well for a long time. Short cut & you'll be back.

Take care considering the price of the tractor if you decide to buy it as is. Not talking just a "couple hundred" to fix all that's likely to be found in there and gear grinding might be called a "late stage" warning sign.

Anybody agree?

 

[LarrySTN]

If as you say 1st-3rd, 2nd-5th, 4th-7th work properly, you likely have a problem with detent on the range shift quadrant. The detent on the 4020 was cone shaped and it is very common for these cones to wear a groove in the quadrant, especially in the gears shifted most frequently. Pull your right battery and remove the detent plug for the range quadrant. Look for a groove between the detent holes in the quadrant.

 

[Resting Relics 1]

4020 looker,
I worked on these sycro ranges a lot in my younger years when I worked for a larger JD Dealer. It's not totally unusual for 6th or eighth to grind a little if you rush the shift. When the syncros and the bottom shaft collars and gears are in good shape you have no grinding. I found that before you tear into it the first thing you should do is to rebuild the shift quadrant and all the linkage. This will very often buy you some time and you should do this work when a transmission rebuild is done anyways so at least your working in the right direction. I agree with the comments on the Forum that when when it finally is unusable any more and your rebuilding don't get cheap. Replace all syncros and packs, gears, collars and shift mechanisms. Do it right the first time and you won't have to look at it for a long while. We always did because a dealer wouldn't risk a do over because a bad part was skipped over. Good Luck
John