T407/TF 727 Band Adjustment

Thanks a lot michael! That sounds like a very possible reason for the problem! I guess I just have to drop the pan and take out the valve house and take a look. Are there any springs, balls, oil lines or something that is attached to the valve house or is it as easy as just removing the bolts and take the house out? Is there any gasket between the valve house and the tranny house or is it only the gasket at the pan?

Halvar
 
harley7985 said:
thanks a lot michael! That sounds like a very possible reason for the problem! I guess I just have to drop the pan and take out the valve house and take a look. Are there any springs, balls, oil lines or something that is attached to the valve house or is it as easy as just removing the bolts and take the house out? Is there any gasket between the valve house and the tranny house or is it only the gasket at the pan?

Halvar
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Doing the rest of the diagnostics, you should only remove the pan and then the filter. Also remove the control lever from the shift lever on the exterior so you can work it by hand. Then look/feel the shift quadrant and determine what has happened.

One other issue involves the same shift system...if the plastic follower is not damaged, then it's very possible that the quadrant has come loose on it's housing (it's a press-fit when manufactured). That is another common occurrence. If it is loose, then it May be removed and the parts reassembled back into proper position and then a very small weld placed on the top to mate the parts together. In fact, the picture I posted does show a quadrant that has been repaired in the past.

To remove the valve body, both shift levers must be removed. The transmission should also be placed in neutral. That allows the parking rod to pull straight out of it's detent inside the tailhousing. No gasket is involved, the valve body simply bolts directly to the main assembly.

Once the valve body is dropped down, there is a large spring that is between the valve body and the accumulator piston. It simply sits in that space and is not a problem to reinstall later. If the transmission has had a transgo or B&M shift kit installed, then that spring will not be there as it was discarded when either kit was installed.
 
This May be a stupid question, but just have to ask to make sure. So I'm doing the band adjustment after installing the transgo shift kit, and it says depending on how many wraps in the bands to back it off different amounts for the rear band. It says for single wrap to do 2.5 turns and for double wrap 3.5. It goes to say that a double wrap has three sections across it. Now I can see three different sections in the front band, but the rear band is all one section, so would it be a single wrap?
 
Mr. Mayben
I have been reading through the trans tech forum for 3 days now, and I have ordered my carl munroe "bible". The trans is out, on the stand, and ready for an overhaul. I just wanted to say thanks for taking the time to explain the workings of the tf 727. This will be my first tranny build and I probably wouldn't be able to complete the task without ihon forum.
 
Hey guys I am new to this forum and am pretty handy with basic stuff like changing radiators, water pumps, steering pumps. But never touched the inside of an engine or transmission. Whle changing fluid and filter on my brothers 86 dodge ram w150 with the 727 I decided to do the band adjustment per the manual. Well I completed zoned out even though it seemed crazy to torque to 72 ft lbs :mad5::(. When I finally realized this could not be right I backed everything off and redid it with ft inchs but the adjustment bolt seemed to be very loose after I backed it off. Have I just trashed the reverse low on this tranny? Could I have done something to band assembly that I could fix wo replacing band? I am desperate here...I am scared sh?tless to button this up, start up the truck and completely trash the tranny. Any help would be greatly appreciated you guys really know your stuff!
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michael mayben

"and to address ron's question...complete loss of reverse gear (as in..."worked when parked, now it won't go") is normally because the band has not been adjusted during it's life and the extreme amount of slop caused the "anchor" on the band (it's a rigid band) to break off when applied onna "cold" tranny and the pieces of the apply linkage and the band are floating around up inside the case! That means major overhaul time to repair.[/quote]
 
Yeah, 72 ft/lbs is a fairly massive amount of wrench torque and seems nearly impossible to achieve in that area without approaching the point of breaking something. Inch pound torque wrenches are not that commonplace anymore, so when dealing with torque settings calling for in/lbs, your best bet usually is to convert that figure into ft/lbs. For example, 72 divided by 12 (inches in a foot) equals 6 pounds. So 72 in/lbs is equivalent to 6 ft/lbs. Of torque, which isn't all that much. When dealing with a brand new reverse band, the standard procedure calls for stretching the band by over-tightening it once (though certainly not to 72 ft/lbs), then backing off the screw several turns before torquing it to the 6 ft/lb spec and backing off two full turns.
I suggest you shine a bright light up into the cradle area where the rear band rests and try to verify that both band anchors are still attached to the band. You'll probably only be able to see one anchor easily, which will be the outer one that engages the apply strut to the intermediate apply lever. Just verify that applying tension to the band via the screw and/or apply mechanism tightens the band to the drum. With the band completely loose, you should be able to rotate the drum freely by hand in a clockwise direction only. With band tension applied, the drum should not rotate at all. If that checks out good, re-torque your adjustment screw to 6 ft/lbs and back it off exactly two full turns from there. There will be a slight amount of play in the apply linkage at this point. The band has to be able to release fully when not in reverse or manual low positions.
 
Thanks for your help trever. I actually did not get anywhere near 72 ft lbs before the cheap 8 sided socket starting slipping. I scuffed up the adjustment screw somewhat but that thing is tough it destroyed the socket. I was able to adjust it using my 1/2 ft lbs wrench and then back it off but I am thinking that it really is a 10 - 150 lbs and is not accurate it enough at 6. I am thinking I should go to harbor freight and get an in lb wrench. I have uploaded photos and believe I have lucked out here but hopefully you can determine whether any thing is damaged. There is a slight amount of play but not much. I have one photo of the bottom of the transmission main seal? Is it supposedly to look like that it almost seems as if it May have been hit somehow. Is it possible to re torque those bolts to try to stop the leak?? I can post photos later if am not clear on what I am asking about. Thanks again.


https://picasaweb.google.com/kporterjr/20120605?authuser=0&authkey=gv1srgcpl4vslni9wdaq&feat=directlink
 
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That's actually a good thing. Sockets are easy to replace. A broken rear band isn't. Hear me now and believe me later when I say you do not want to have to jerk and gut the entire trans just to replace a messed up rear band, but that is exactly what it would take. You might as well do a full blown overhaul at that point since you'd already be more than half-way there. Some manuals actually spec 120 in/lbs or 10 ft/lbs for the torque setting. In that case, you would back the adjustment screw off an additional quarter turn to compensate for the extra torque. The 72 in/lbs is the more commonly referenced and accepted figure. Either way, the end result should be nearly identical.
Something looks a little odd to me with respect to your intermediate apply lever that is directly engaged by the adjustment screw. Perhaps the shape of that part was changed as the tf's evolved. I'm just wondering if it is engaging the apply strut to the band anchor properly. I know it is very difficult to see these things while lying on your back under the rig. I'm just saying you need to make double damn certain that things are totally jake in that area before buttoning it up. If you can see obvious band clamping action when tension is applied, which then releases when the tension is released, you should be good. When the screw is backed off the two turns, and the lock nut snugged down, there should be several threads visible between the lock nut and the top of the screw.

Addendum...pretty nasty looking fluid in that thing. It was long overdue for some new kool-aid and a filter!
 
Trever, big heavy knuckle sigh of relief. I wanted to get the pics up so you could look at it. I was able to back the screw off and readjust it. I did not have the new wrench yet so I just hand tightened it and could see the band flex a little bit. The rocker assembly or what ever that arm did completely release and then re engaged when I hand tightened. I still need to pu the new wrench and socket and readjust it. I am now cautiously optimistic vs lousy nights sleep mon night. Thanks again!

Keith
 
That's good news. I am especially sensitive and skittish about problems in that rear band area having just gone through my own nightmare scenario. In my case, I had to first overcome my understandable denial that an experienced trans builder (not myself) could have installed several parts incorrectly. Then I had to overcome my ignorance as to how those bungled items should be properly installed. Once I negotiated those hurdles, I managed to get the thing working the way it should have the first time around. That was only after much personal frustration and several parts being needlessly destroyed. Pretty tough way to learn how to service these units. I don't wish it on anybody.
 
Did this tonight and my inch pound torque wrench failed. Looks like I over torqued this by an unknown amount but enough that it took some effort to remove the adjusting nut with a 3/8" wrench. The band in question in the low-reverse band. Fortunately I was using the craftsman socket you suggested on page 1 or I wouldn't have been able to get it off!

What's the likelihood that I damaged the band?

Not my week for transmission repairs...of course I am popping my cherry on the subject. Prior to this week the furthest I had been inside one of these was to change the filter and I made sure not to touch anything! Looked like a magic spell in there!
 
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What did you have your wrench set to? 72 inch pounds divided by 12 converts to 6 foot pounds on a normal torque wrench, which is practically nothing. Many regular torque wrenches don't even go that low. An open palm and a tentative elbow will prevent most folks from exerting more than ten foot pounds of pressure on a wrench.
So, make sure the locknut is loose. You might even need to spin it all the way off to get more of a bite for the socket on the square head. Connect your 3/8ths inch drive, 8-point socket to a standard ratchet wrench and back the adjustment out to release the tension. Get a good torque wrench that will go as low as 6 foot pounds/72 inch pounds...same damn difference. Then recognize that torque factor is pretty low, so the torque wrench should break/click well before your popeye forearms puff up to full flex. The idea is just to set a baseline tension on the bands, not to stretch them to the breaking point.
 
scoutboy74 said:
what did you have your wrench set to? 72 inch pounds divided by 12 converts to 6 foot pounds on a normal torque wrench, which is practically nothing. Many regular torque wrenches don't even go that low. An open palm and a tentative elbow will prevent most folks from exerting more than ten foot pounds of pressure on a wrench.
So, make sure the locknut is loose. You might even need to spin it all the way off to get more of a bite for the socket on the square head. Connect your 3/8ths inch drive, 8-point socket to a standard ratchet wrench and back the adjustment out to release the tension. Get a good torque wrench that will go as low as 6 foot pounds/72 inch pounds...same damn difference. Then recognize that torque factor is pretty low, so the torque wrench should break/click well before your popeye forearms puff up to full flex. The idea is just to set a baseline tension on the bands, not to stretch them to the breaking point.
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I hear ya. My 3/8" craftsman torque wrench is digital and doesn't go below 10 ft lbs. The hf "pro" series wrench is my inch pound wrench. It's the clicker type and it was set to 72 inch pounds. I just bought it last week specifically for this purpose. Worked fine on the kick down band adjustment. Then immediately after that I did the low-reverse band adjustment and it didn't click. I removed the lock nut so it was just the screw. I wasn't benching the truck or anything but it's a shorter handle that I don't have a feel for yet and I was expecting it to "click at any time" and it didn't. I stopped and then it took some effort to get the screw off - had to press the socket with my hand and turn perfectly to keep from rounding the screw but it came eventually.

Question is did I harm anything? How could I tell?
 
Probably didn't hurt anything by that description. The band might snap if you tighten it too far, but you'd almost need the lock nut out of the way to go that far. You'll know if something's wrong on the next try if the tension screw just keeps turning and doesn't seem to snug up when you think it should. Sorry for getting a little "scoldy" on you before. That could have happened to anybody.
 
scoutboy74 said:
probably didn't hurt anything by that description. The band might snap if you tighten it too far, but you'd almost need the lock nut out of the way to go that far. You'll know if something's wrong on the next try if the tension screw just keeps turning and doesn't seem to snug up when you think it should. Sorry for getting a little "scoldy" on you before. That could have happened to anybody.
Click to expand...

You're good. I tend not to get worked up over folks' posts on a forum unless they have their caps lock set to cruise control or apply choice expletives :icon_mrgreen: plus I left out some of the details you inquired about.
 
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Clicker type
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Clicker type torque wrenches are pretty iffy in their lower ranges, and not the best for inch pounds below 10 ft. Lbs.(120 in.lbs.) on top of that, most affordable ones have a wide latitude in accuracy. The better ones run around 2% mid-scale but usually belong in the $200 price range and above.

For this type of work, and also for bearing pre-loads in diffs and transmissions for example, you can't beat a beam or dial type wrench. Aside from being affordable, they're damn accurate though you have to physically see their reading, not hear a click.

There are some good deals you can find on the net for park, sturtevant, sekonk, cdi, and even snap-on (cdi)for example.
 
I don't know if mr mayben is still around, but I have a 727 issue that hasn't come up in this thread and maybe someone can help/advise.

Scout 2 with a 727/d20 behind a sbc 350. Runs and drives fine, kick down seems to be the midrange type (not the full throttle one). When the vehicle is warm and I come to a stop lights, there is this strange cluck/cluck sound that is regular and is def. Rotating parts. Sounds like banging a wrench on an exhaust pipe, but not loud. I can feel the knock thru the t-case shifter, not the tranny one. When I start off again, the knock get a bit louder for a few seconds and then goes away and we're off down the road. I haven't done the band adjustment(s) yet. I know its not been done since 2007 because the young guy I bought it from in oct didn't know squat about cars and drove it like it would never break.

It is not in 4wd, checked that. Why would I feel parts reciprocating thru the t-case when nothing should be turning at a stop.

Thanks
off to get a filter.
 
Thanks fd-

they are all tight. I wouldn't think that was is because the noise does not occur in park or neutral. The shift linkage is off a little, I have to slide the selector onto the 2d perch, then when drive engages, I push it forward onto the d position for it to use all three gears.
 
Mayben hasn't been around in quite awhile. Rotational type noises are not generally associated with failed bands or improper band tension. Band issues will reveal themselves in the form of erratic or delayed shifts, or no motion in some or all gear selector positions.
Can this noise ever be produced when the vehicle is at a full stop in any selector position?
Have you tried coasting with the selector in neutral when the noise presents to see if that makes a change?
How about if you shut the engine off while coasting?
What happens when the brakes are applied and then released, both hard and gentle?
 
Ok I have a similar issue.
The noise can also be felt, almost like a broken tooth. I can only hear and feel this under load, like taking off from a stop sign. If I coast no noise. In park or neutral no noise.
I pulled the tcase cover and everything looks like new. I pulled the difference cover and pulled the carrier to check the locker and it looked fine too.

I'll check those convert bolts.
I pulled the pan and adjusted the band's, no help.

Any other ideas before having to pull the transmission for a look inside.

Thanks
 
Craig said:
ok I have a similar issue.
The noise can also be felt, almost like a broken tooth. I can only hear and feel this under load, like taking off from a stop sign. If I coast no noise. In park or neutral no noise.
I pulled the tcase cover and everything looks like new. I pulled the difference cover and pulled the carrier to check the locker and it looked fine too.

I'll check those convert bolts.
I pulled the pan and adjusted the band's, no help.

Any other ideas before having to pull the transmission for a look inside.

Thanks
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No noise during neutral coast rules out stuff at the corners (bearings, wheels, big tires, dragging/faulty brake components) as those items are either rotating or almost in contact with rotating items while the rig is coasting or powered. You've got some components not found in most scouts...your range box and your divorced t-case. I know you've had the case inspection cover off for a visual and didn't see anything amiss. What about the range box? I'm just curious as to why you're most suspicious of the transmission. From my outside looking in perch, I'd be casting my suspicion more towards your non-stock gear boxes and associated drive shafts. There's actual gears and teeth in those boxes. Yes, there are rotating parts inside the auto trans, but pressurized hydraulic fluid is doing most of the work.
 
Craig
it's the same for me as far as what you described for the noise. Nothing loose or dragging. None in coast or neutral. I don't have the stacked up gear boxes like you have, and since there is no interior finishes in mine I can hear this noise pretty well and I can dampen it by gripping the t-case lever. I thought it was the spud gear at the end of the output shaft hitting setting in the t-case, but it shouldn't be turning when I'm at a stop. Since the shifter is bolted to the body and it happens 'under load' could it be a loose or broken teams cross member mount?
 
How is the t-case shift lever bolted to the body? It should be completely independent of it. Or did you mean the trans shifter? That is technically bolted to the floor, actually the dog house cover, but its only attachment to the trans is via a cable. I don't see that cable transferring a foundation rattling knock into your cab. Now, a bad trans mount or loose cross member could be transferring unwanted movement up through the t-case lever since that lever is physically attached to the t-case, which is physically attached to the trans, which is physically attached to the engine. And since you say grabbing the t-case lever dampens the noise, that has some plausibility.
 
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The ord box is pretty hard to look inside. The 1/2" oil fill plug is about your only option.
I have a bore scope and can look inside.

The transmission was rebuilt, ran fine for about 50 miles. Then the noise.

I will look inside the range box.
 
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