7400 PowerQuad no 3rd speed gear?

MonteFish · Jun 17, 2016

Have an older 7400 with the lower transmission serial number.
3rd speed selection in any range, you can hear the transmission whining really loud, but will shift in and out of any other gears forward and reverse.
and yes it does the same thing in reverse speed 3 as well...
Any Ideas?
-Monte :evil:

MSM · Jun 17, 2016

Probably have lost the 3rd gesr clutch pack. I had 2 7500's on the farm in Brazil that did the same thing. They would pull fine in 1+2,but nothing but noise in 3rd. One broke a snap ring which let the clutch pack fall apart, the other wore out the discs, both around the 6000 hr mark. Dump the oil and pull the suction screen. You should see evidence of what is happening (pieces of clutch disc,metal shards).

MonteFish · Jun 20, 2016

(quoted from post at 16:53:12 06/17/16) Probably have lost the 3rd gesr clutch pack. I had 2 7500's on the farm in Brazil that did the same thing. They would pull fine in 1+2,but nothing but noise in 3rd. One broke a snap ring which let the clutch pack fall apart, the other wore out the discs, both around the 6000 hr mark. Dump the oil and pull the suction screen. You should see evidence of what is happening (pieces of clutch disc,metal shards).

This particular one has 7777HRS, already had this pulled apart and split.. the clutch plates on both sides seem to be fine, replaced the pistons for both forward and reverse clutch brakes, thinking there may have been an excessive leak allowing them to slip, but that wasnt the case. any other ideas?[/img]

MonteFish · Jun 24, 2016

Just an update. after replacing a few shuttle spools for the speed valve, i still have no change in the absence of 3rd gear.
All spools in the valve looked fine as well. no scoring nor scratching or wear was found in the body either? while apart i made sure
all parts moved freely with a little oil applied to the spools, clutches and even ran air through the piston brakes?
any idea to why 3rd speed gear still wont completely shift and only whine like a loud electric motor?
-Monte

MonteFish · Jul 9, 2016

So at this point, alot of valve spools and springs have been replaced in the speed valve, the unit seemed to work fine for just about a week, then after the weekend the unit decided to no longer move in speed #3 and whine when clutch is released.
Even though ive had this all the way apart and examined the fine details, is it possible that the B3 disk has worn into the direct drive drum... there is no aparent wear or excessive marking but im afraid the teeth arent grabbing all the way and thats the current whining im hearing...
Main question was if anyone actually has expertise in anything near this matter for transmission theory of opperation.
-monte

7400 PowerQuad no 3rd speed gear?

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