727 upshift mystery

Should be minimal. How'd the fluid and filter look and smell when you drained it? What type of fluid are you using?
 
The fluid looked fine, maybe a shade dark but definitely not dirty. No burnt smell. The filter had a few metal flakes that I think are from the new bushings breaking in? I’m using valvoline dex/merc. I bought Castrol transmax today when I got the new filter and gasket. I’m starting to get concerned more about the clutch packs because of the air leak. It held fine in 1st but it did slip in 2 and 3.
 
I had another thought about the clutch packs. The front clutch controls reverse and 3. The rear controls 1,2,3. Well I have a solid reverse and a solid 1. That covers both clutches so makes sense to me that the air leaking by the clutches must be ok. Am I just convincing myself not to pul the tranny again or does the logic work in your mind also?
 
Dex/Merc is the right stuff. This could prove to be a tough nut to crack without a full unit autopsy. The more common and easier to cyber-diagnose failures tend to involve the complete loss of motion in one or more selector positions, with normal operation in the others. I just can't let go of the notion that this is a fluid pressure problem, though. Either too much, not enough, or within spec, but not happening at the right time. And fluid pressure is predominately controlled within the VB. Were you meticulous in your parts cleansing, especially with the VB...I mean to the point of being an anal retentive maniac in getting stuff clean? Are you sure you got all the check balls where they belong by size and location? I mean, you admit to getting one spring wrong. Isn't it possible that something else within the VB was assembled incorrectly? I'm just spitballing here. I've been inside these things up to my armpits a few times, but that by no means makes me an expert. I hate to say it, but I have an idea you'll be dropping this trans back out for another session on the bench before too much longer.
 
Your absolutely right that I could have jacked the vb up the first time. I took my time this time and checked every valve,spring and ball. I compared everything to both the Munroe book and shift kit directions. I’m confident that I got it right now. I may have had the throttle valve plug in backwards the first time but it’s dialed in now. What do you think about the clutch pack situation. I know you have no crystal ball and can’t fix everything on the inter web but it helps me to kick ideas around with someone who has more knowledge
 
I've been looking through Tom Hand's online guide to the TF727 during this time, and there just isn't any one thing jumping out at me that could be causing the symptoms you've noted, other than incorrect fluid pressure. Sure, there could be a problem with either of your clutch packs. If there is, you won't be doing anything about it while the trans is attached to the engine. When you had the VB halves apart, did you look them over carefully for cracks or damage in the passageways? Tell me more about this kit you installed. What brand is it? What modifications were required? Please be specific.
 
I’m thinking the same thing about line pressure, fact is it was way high when I put a gauge on it. I was just doing some checks when I found the air leak in the clutch packs. I’ve read that the Teflon sealing rings can be harder to seal? Maybe I’ll bump my air pressure up and recheck. I’ll get the specs off the box when I get home but the shift kit came in the rebuild kit. Got it down the road from transparts warehouse in Redding. It wasn’t real difficult to do. 1)Drilled a hole in wall of throttle pressure passageway
2) Took out ball from separator plate
3) Enlarged a few holes in separator plate
4) Replaced tp spring, converter pressure spring
5) Adjusted tp and line pressure screws per instructions
This time I did back the line pressure off quite a bit. I had it maxed before for stiffer shifts but it was within instruction specs.
I know I’m taking up your time but I appreciate your thoughts
 
You have two options at this point. You made some changes to the VB which may or may not have a noticeable effect on the issue. On one hand, you could slap everything back together, fill with fluid and see if the situation has improved. On the other hand, you've got the fluid drained already, so you could go ahead and drop the trans out to retrace ALL of your steps. ATF gets pretty spendy when you do multiple drains and fills, plus it makes a damn mess every time you do it. But, trans R/R and tear down/build up is a lot of work. I guess if I was in your shoes, I would probably opt for testing what I had in the hopes that I nailed it this time, but with the resolve to drop the thing down if it was still misbehaving. I don't really see a third choice.
 
Copy that, That’s exactly where I’m at! I’m leaning heavy towards buttoning it back up and giving her hell. It’s kind of a gamble either way. If I go through the tranny again and it was the vb that would blow. Let me hit you with one other possibility- the governor. Could that little sucker jack up the line pressure enough to raise hell?
 
DKindley said:
Copy that, That’s exactly where I’m at! I’m leaning heavy towards buttoning it back up and giving her hell. It’s kind of a gamble either way. If I go through the tranny again and it was the vb that would blow. Let me hit you with one other possibility- the governor. Could that little sucker jack up the line pressure enough to raise hell?
Click to expand...

Yes it could. Did you take a pressure reading at the gov port?
 
Hate to admit it but no. Like an Adam Henry I got the high line pressure reading and no front servo reading and I knew it was messed up so I pulled the vb
 
Sucfreakincess!! Scoutboy74 thank you for your help. I put the vb back in and it shifts and drives like a dream! To clarify what I actually fixed(more accurately unfubarred) I had put the kickdown sleeve on the throttle control valve in backwards. The small end faces out. So I essentially created a massive line pressure increase, actually maxed line pressure at all throttle positions- ya no good! Any way it worked and I,m back in business. Note to self- don't try to work on your valve body after working a graveyard shift and trying to stay up the next day.
 
If anyone has been following along or has this issue I learned something very important. I almost yanked my tranny because I heard air bypassing the clutch packs. When you air check the clutch packs, its ok to have some air leaking in the clutch pack itself. As long as the clutches "thump" with a quick burst of air you should be fine. I'm by no means an expert but I have been researching and studying the crap out of these 727's. If I can pass along any info don't hesitate to ask. Scoutboy74 was a huge help and sounding board and I'd like to help the next guy too.
 
Outstanding! Good job...the second time around.:dita: One little thing can really bite you in the backside sometimes. Great learning experience for you, though. Now, if you can just keep those lads from shock-loading the damn thing. I imagine they've learned they're lesson on that count. I did the same thing once in my high school hot rod, trying to impress a sweet Betty in a Hoopdee Accord stopped in the next lane. 351 Cleveland mated to a C-6 auto smoked the tires up real purdy once the light went green...then clank, clank, clank and huge clouds of white steam billowing out the seams of the hood. Miraculously, I didn't damage any of the drive train, but the fan blade sure ate the hell out of the oversized radiator I'd shoe-horned in. Betty Boop was very impressed as she drove off without so much as a backwards glance, never to be seen again. Come to find out, they really aren't that impressed by displays of vehicular abuse. Who knew? Some alcohol may have been involved as well. Not one of my prouder moments. Feel free to pass that one along to the boys if you like.
 
Oh that is such a familiar story. I think laying on their backs in a lake of tranny fluid will make the boys think twice next time. Ahh not if theyre like the old man haha. It was still a good learning experience for us. Oh and I did get two sweet SO ratchets!!
 
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