You might remember my troubles with the downshifts not happening.
Today I went on the lift, changed the transmission mount and attempted to adjust pressure per the book. Fuel line with a gaige on one end and a grease pump fitting on the other.
Pressure at idle is okay and in drive it’s just the same. Stepping on the gas produces a pressure rise of .2 bar- just a fifth of what it should be. Cable adjustment in either direction is hopeless.
Could it be the wrong dipstick, wrong fluid level?
After changing the tv cable (mechanically everything worked well inside) and thus fluid, filter, all that’s left is swapping in the BW65 valve body I still have as spare. My lift-providing mechanic agreed. Edit - swap not feasible.
Any suggestions? I will take anything but shot glasses of brakefluid, for now. Nobody who ever had the issue in such persistance?
David, if you haven`t already, then spend the 6 UDS and buy the online ATSG BW65/66 manual. Rather than swap in another valve body of unknown quality. Clean your existing valve body AFTER YOU GET THE MANUAL. Be very clean and well organized.
It is unclear to me what pressures you are seeing in neutral and drive can you express them in PSI? Google tells me 1 bar is 14.5 PSI. Seems low. Pete
Okay, I will, Pete. Of course I don’t know anything about the spare valve body. Should I measure spring rates in the known bad one when cleaning or do they tend to be okay?
I‘m seeing 67psi (4.6bar) in neutral as well as in drive, and at 1400 (and more) rpm this rises by about 3 psi where I should see significantly more of course. The base, idle pressure is okay per the book!
I‘m not afraid to dismantle the valve body. Will shoot for the weekend if the lift is available.
The downshift cable adjustment is very specific and described in the workshop manuals. The pressures - should be measured in ‘D’ - reading between 55 and 75 psi. Rpms should then be increased by 500 rpms to give readings between 75 to 115 psi - with a minimum difference between the first and second readings of 20 - 25 psi. Slackening the cable increases the pressures, shortening it decrease pressures.
Any other procedures is plain wrong - and leads nowhere, the pressure readings in neutral and while driving is of no consequence…
The point of the adjustment is just to tune the gearbox to gas pedal position and rpms, using the procedure described…
Getting the specific BW manual as Pete suggests is certainly a good idea. There may be issues that downshift cables cannot rectify - whether related to the gearbox itself or the engine condition. And the BW manual will have the complete description of the downshift cable adjustment…
So am I! The pressure in D is spot on. Rising the rpm by 500 does not change much at all! It has to be in the valve body. I naturally did everything exactly per the book and then kept changing the cable length to no avail. The cable is still hooked up mechanically. Scary to start a car with a ladder for an exit and several feet of air below! Even more so changing the cable length, security first.
As you know I‘ve already gained some insight concerning the internals and by now it has to be something amiss between the governor valve and the TV cam. I hope.
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I should have trusted you to do the right things, David…
The spec pressure in idle implies that the oil pump and primary regulator are working OK. That the cam actually moves with pedal input, the downshift valve is a vague suspect. The governor is indeed ‘active’, or ‘on line’ throughout, but it is a wide field of suspects. No doubt the specific BW manual will illuminate the problem - and may provide a direct clue…
You said there were problems with downshifts - does ‘manual’ downshift work?
I think the valve bodies of the 65 and 66 are more or less equivalent. A direct swap-in with the 65 body may be a more conclusive test in assessing the fault - before cleaning the 66’s? If there is no change it would imply that the fault is not in the valve body? And if there is a change; the cleaning of the 66 is confirmed purposeful…
And if the 65 operates the box perfectly - you can clean the 66 at some leisure…
I can clean the 65 body and swap it in before redoing the 66 body (so I have a known half-good valve body after cleaning). swap doesn’t work, read below
The governor works. Manual downshifts work. I‘m always starting out in 1 and all it does is upshift too quick and not down again but when slowing down. I was quite happy with the pump being fine, as you can imagine.
The book says check pressures and if need be change valve bodies so yeah, I still know things to do for the weekend.
The whirring noise in 1st by the way almost disappeared after changing the softened gearbox metalastic mounts; I remember mentioning that in the first thread.
Also, I now have the ATSG manual.
Sounds good!
David
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Unless existence of evidence that the 65 is defective, David - I would put it in without cleaning it…
Though cleaning it will give some practice for the real thing - if it is in working order tinkering will not help. If it works ‘as is’, you know you have one good unit - saving one step. If the 65 does not work; you have the 66 on the bench as planned anyway…
While cleaning the valve body is fairly straight forward with the manual in hand - there are finer points to it. And then here is the Murhy’s Law and the ‘fiddle factor’ twice over with two cleanings…
It will go in clean.
Why? There was some goo in the spare 65. I have no idea about its condition. I want to have some clue about wear and -patterns and it helps me to know that I cleaned it by myself.
After all a little speck of goo could be lodged somewhere inside and the swap was for nothing which is a risk by itself! Should it work it‘ll be left in until the next time something goes
David
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It’s only after all the facts are known that we know for certain which process would have been best, David…
In the meantime we just have to do as we think fit - and hope for the best. Ultimately, all issues will be resolved - 20/20 hindsight is of little help, though I believe in not disturbing sleeping dogs before the hunt…
Partly. It works now, and maybe (and not more than maybe) it was the valve that is moved by the tv valve and governor pressures; the tv valve moved freely but after moving the assembly a bit and putting it all back together it worked.
I also reset the clearance of this valve per the green book and found a ‚double’ gasket behind the fluid filter extension. One for free!
The BW65/66 valve bodies do not interchange as the pump suction tube won’t go through the hole in the valve body without modification! there‘s a step in the 65 casting.
The ATSG manual is well done, but I cleaned the valve body with the information from the workshop manual - and can be done without if careful. Good read, still.
Thank you all. What’s left now is pressure measurement and figuring out why the transmission mount knocks (where a PO went wrong probably). It’s metal on metal when the spring expands, and has always been like that… I‘ll see.
David
By the way: Fluid was still clean red, no debris after about 100 miles or maybe more without tv function, low pressure. So it can work in emergencies.
Nobody who ever had the issue in such persistance?
