7250 transmission clutch pressure check

[FryGuy]

I've pressure tested the clutch pressures on my transmission control valve and found very  low pressures on the even gears.  I capped off the main clutch but not the odd and even tubes. It's not very clear in the manual but it looks like I should cap those off to confirm if I have a leaking clutch pack or a leak in the control valve.  Also would a low accumulator cause the tractor to not drive in all even gears?

[756puller]

Can drive tractor and lay on the brakes, if it kills the engine the clutch packs are good, if the tractor doesn't act like it's gonna die than the clutch packs are burned up

[FryGuy]

It won't move at all in even gears but it happened all of a sudden which was why I'm trying to figure out if the clutch pack suddenly let go or if it's in the valve.

[HydroTek]

Need to cap the lines to the O E clutches just to be sure

There are fiber check valves in the shift valve that I have had blow out and lose pressure 

 

[GaAgTech]

The 7200’s and 8900’s had internal odd/even lines. The only line external on top of the speed transmission above the odd/even (input) shaft is the lube oil line. So they can’t be capped off  

7100’s had external lines that could be capped off easily  

Like Hydrotek stated, there are some check valves that can blow out and cause the odd/even clutches to modulate with the master clutch, which they are not designed to do. This will lead to clutch pack failure for odd or even or both. 

[FryGuy]

So I'm looking at splitting between the flywheel housing and speed transmission if there's no way to eliminate the valve?

[FryGuy]

I see now where I was looking at the wrong section for 7200 with later serial numbers.

[GaAgTech]

After I posted my response I was questioning my memory as to whether the before serial # break on the 7200’s had the external lines like the 7100’s or not. Messicks did not show a serial break for 72s and I’d have to dig out my service manual. 

The book way and the only way I’ve repaired a speed transmission was to split between the speed and range transmission, rolling the speed and engine out from under the cab. 
Then remove the speed transmission from the engine. 
All the speed shafts shim from the rear of the speed transmission, so even if you were able to remove the shafts from the speed transmission just by splitting at the engine, you would not be able to correctly shim the shaft/shafts without accessing the rear of the speed transmission. 

You may reuse all the original bearings and the shims may not change. But you wouldn’t really be able to check the shaft endplay to be sure. 
I never wanted to go into it twice. 
I do highly recommend removing the transmission control valve and replace the three check valves. Two of them are on the mounting plate and one on the middle valve housing if my memory is correct. 
You’d also want to look closely at the outer part of the shift cam where the detent roller ride. This part can wear down with a lot of use. 

[HydroTek]

I usually just remove the cab -- makes it so much easier to do the heavy work , and that cab is not difficult if you have a forklift 

[SDman]

Internal odd/even tubes were on the last 71xx series transmissions, transmission serial # AJB0055133(that's TRANSMISSION serial #, not tractor serial #).

To the OP, one simple thing you might check....pull the drain plug from the bottom of the speed transmission and see if you have some debris come out of the drain plug. If its slipping that bad, you will probably see some "chunks" coming out of the drain plug hole. Have had some that had so much debris there that hardly any oil would come out of the drain plug.

[Dan Robinson]

5 minutes ago, SDman said:

Internal odd/even tubes were on the last 71xx series transmissions, transmission serial # AJB0055133(that's TRANSMISSION serial #, not tractor serial #).

Correct. Have a 7130 in the shop right now with a late serial that has internal lines.

This 7130 had a real goofy issue last fall, finally got it apart this past month. 

Tractor would die if left in neutral, hold the lever over into forward or reverse it would stay running.

Found one of the penny sized $73 dollar check valves came apart. Dropped lockup pressure off.

Tractor was operated long enough on low pressure that it slipped Even clutch long enough that it welded itself together. 

When a magnum is in neutral, reverse and I believe 3rd? is locked up to stop the speed trans from turning. With Even clutch pack welded together, when lever was in neutral it would have 3 packs locked together causing it to kill the engine. 

Talk about a brain twister the afternoon I went out last fall to figure out why the engine kept dieing. 

[Dan Robinson]

Here a check valve from the TCV. 

$73/ea from the dealer. 3 are needed. 

And even clutch damage. 

[PJW360]

Lots of good advice given  already

you could drain the trans oil and pull the suction screen it will give you a good idea of how much debris is in the system then look at the  TCV

I did my 7220 in 2022 I took cab off just so much easier as dealing with very heavy sections and lots of steel pipes and as it is a big job I did both boxes -clutch plates -seal -orings while I was looking at it not cheap but dont regret it now

someone had been in it before found all sorts of probs someone had even poked through tcv  filter screens a dealer manual is a must and good luck