2940 - Hi-Lo Issues

Hello to everyone. New to YT and the forum. Need some advise and direction. This is a bit lengthy but please bear with me. A little history - JD 2940 2-wheel drive, w/Sound Guard Body (SGB). Have had the tractor for about 15 years. Last fall the steering and implement lift started going haywire so I drove the tractor to a repair shop (about 8 miles or so). This particular shop is the only independent shop in the area (he specializes in JD and has been in business for over 30 years). Anyway 3-months and $5000.00 later I have a new front pump, pump coupler, steering cylinder kits, water pump, and a new hydraulic oil line grommet in the trans (had to split the tractor). Back home (drove it) and the rockshaft housing is leaking pretty bad. Drove it back to the shop. 2-weeks and $500.00 later I have a new o-ring ($1.00) in the rockshaft. Seems like R&R of the SGB is a major undertaking. Now to the current problem. When I got the tractor back as I was hooking up the ditch bank cutter to do some bush-hogging I noticed the triangle warning light on the dash. Not seen that before. Checked and that pointed to other warning lights, one of which is the "transmission low pressure" light. Further investigation found that that bulb was missing (so I was not seeing it). I put a bulb in now I see the "Transmission Low Pressure" bulb glow. I realized that the light came on only when the Hi-Lo (Turtle/Rabbit) was in Low. In High the light would go out. I checked with the repair shop and was advised that he would just use in in Hi and not worry about Lo. That part of the trans was to difficult and expensive to get to and he would not advise it. I'm dealing with 16 acres and have used the tractor as he recommended to bush hog ditch banks; pulled a 9-tine chisel plow and 12-foot field cultivator preparing the field for planting beans. I've even used it in Low periodically for end turn arounds and when the chisel plow would load. It seems to work fine in all gears, ranges and conditions. That light really bugs me. Something is not right and I want to fix it if possible or $$ feasible. My reading tells me that the Hi-Lo Clutch Pack operates with Hydraulic pressure in the Hi range and Clutch disc Friction in the Lo range, so why the low pressure light in Lo and not Hi range. Has anyone ever experienced this? Could the mechanic have done something inadvertently and not realized it. Is there a simple pressure test to determine where the problem might lie. As I said, R&R of the SGB is a bear and having to split the tractor again and go into the trans is my last resort. I have done nothing at this point. Any advise is appreciated. (Apologize the lengthy post)

I am VERY curious as to WHY the front pump was replaced ?

Yes I too would wonder about the front pump being replaced.
I would also like to know what this grommet you speak of was.
When I do any work on one of these I do not remove the cab,but rather bring the powertrain out from under the cab.As well if you are in there you redo the PTO and Hi/Lo while you are there, its time and money well spent.
Its easy to criticize other peoples work but I don't think you have been dealt any favours to this point.
I would plumb a lube gauge in an monitor lube pressure in Hi and lo......I am thinking that your lube pressure will be signifigantly lower in lo indicating a leak in the system.
I would do the job here (north of the border) as it seems the weather won't let me plant corn!

More than likely trans light comes on in low range of hyd hi-lo because either the sealing rings on the low speed drum is leaking. IMHO repairing hyd hi-lo isn't much more complicated than R&R of traction clutch.

It's been a long time but doesn't the hi-lo require 2 splits ? Still not a bad to do job. I worked on one in a 2840 that was torn up from pull starting it. The 2840 was not bad at all to work on , but it didn't have a cab in the way of everything either.

Mike
You're probably correct on the 2 splits required as It's been over 30 yrs since I've seen the internals of a JD tractor trans.
Jim

Hey Mike M. Thanks for the response. It appears that as the hydraulic tube grommet in the trans was shot, leaking profusely, insufficient oil was reaching the front pump reservoir thereby starving the front pump which in turn gaulded the internals. He showed it to me and it looked pretty bad.

Thanks Tech 7. Too wet here as well to plant beans. A waiting game. Will most likely find the pressure check port and do as you suggest. I have the service manual for the 2940 and the manual indicates one split after removal of the SGB. Never done it, so hoping for some prior experience help. I think your advise is best, check everything when in there and fix anything that needs fixing.

Hey TX Jim: I have the Service Manual and can see the Sealing Rings and Piston in the Hi-Lo Clutch Pack diagram. Just wondering might the problem be in the pressure control valve (which is adjustable by shims)- Any insight on that approach?

(quoted from post at 15:55:33 05/04/16) Hey TX Jim: I have the Service Manual and can see the Sealing Rings and Piston in the Hi-Lo Clutch Pack diagram. Just wondering might the problem be in the pressure control valve (which is adjustable by shims)- Any insight on that approach?

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I'd suggest to do as Tech 7 suggested and attach a gauge to check lube pressure.

I wonder if any of those tube grommets are used to feed the hi and lo ? might be causing that issue too ?
I have very little experience on these "new" (now what 30 plus years old ?) tractors. I know I really like these utility models when they work and many people chase a lot of problems on them when things go bad. My uncle had a 2940 4x4 without a cab. I really liked that tractor. He bought it new and had no issues with it at all until he sold out the farm eq.

When I go in any utility tractor, I reseal everything (hi/low, pto, trans pump, rockshaft, mfwd clutch and pto brake). I always put a new pipe from trans pump to the filter. It is expensive but if you get another 15 years out of it, it will pay for itself and also I don't like taking the cabs off more than once.

I'll agree with tech7. You haven't been done any favors. Questions I would want answered is exactly where was this grommet? Because if that front pump starved to death there's a good chance the tranny pump did too. Yes your tractor has a reputation for blowing the seals and pipes. Have the updated pipes been installed and if not - why? (should be a threaded hole above the filter on the boss to secure that new pipe) I just can't imagine splitting her and finding nothing but a grommet to replace.

Hey fellows: Thought I'd provide a little update. Been really looking hard at all possible problem solutions. As I said the SGB was removed and reinstalled twice in the last 6 months. Problem was quite simple. Wire to the Transmission Pressure Switch was connected to the Hi-Lo toggle/rocker switch and the wire to the Hi-Lo toggle/rocker switch was connected to the Transmission Pressure Switch. So whenever the Hi-Lo was shifted to Lo, the transmission Low Pressure Warning Light on the Dash came on. I arrived to this solution by checking pressure at the pressure check port as suggested; pressure good-145 lbs, checked pressure at the High-Lo rocker port; 145 lbs on Hi and 0 (Zero) on Lo. Something was weird here so after discovering where the actual Transmission Pressure Switch was located, the solution came to me. Switched the wires, and voila. Transmission Pressure warning light works properly and now the light on the console that should indicate when you are in Lo (Turtle)works properly also. Glad I didn't split the tractor. Would not have found any problems and then would have been completely baffled. Just had my 70th birthday yesterday and this was a first class present. Thank you guys to listening to me go about it and I appreciate your input to the problem. Hope this solution could be of some help to any one else that has this similar predicament. p.s. need to fine me another tractor mechanic!!