72 inch pounds, 2.5 turns out, right? Even if the 68 v-8 guts are in a 77 slant six case with slant six low-reverse band?

The Kickdown band is 2 turns. (That's the front band.)

The L/R band is going to be based on what year the lever and case are from. Up to '73, 3-1/4 turns. For 1974 to 1983, like your 77 case, it will be 41 inch pounds and 7 turns out.

I don't know that the valve body will play into this. The servo and lever will. I'd set up for the servo and lever adjustment based on the later case. The band doesn't know what the guts are inside the drum. It just has to be able to stop the drum. The V8 Case uses a different lever and band. They would be 4 turns out. The torque for these have a similar change that aligns with the years noted above.

2¢

CJ

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Thanks CeeJ. So, if I am using 68 v-8 guts in a 77 slant case with 77 lever and valve body, I should do 41 inch pounds and back it out seven turns.

Here is the situation.

Last weekend I hurriedly stuffed the rebuilt 68 V-8 904 guts into the 77 case to get a working transmission in my brother's van. Transmission swap went smoothly last Saturday. My brother drove his van all week long and said the transmission worked great in all gears and at low and high speeds.

Fast forward to yesterday. My brother drives down to my place from Seattle. Again, no problems with the transmission. We get in his van to run some errands and as he begins to back up my driveway (I have a fairly steep driveway that slants towards my house, probably about 15-20 degree slope) the van starts moving, slows down, there is a loud PING from the transmission, and the transmision no longer has reverse.

I thought it might have been that the strut for the low/reverse band popped out or maybe even the low/reverse band broke. This morning I go out to start troubleshooting. First test I did was putting the van in reverse (one can always hope, right?). Still no reverse. Then I put the transmission in low ("1"). It DID go into gear nicely on low ("1"). Hmmmm. There goes my suspicion that the problem was with the rear band.

I drop the trans pan and, sure enough, the rear band is still in one piece and the strut is still in place. I checked the tension on the rear band and the lever had an awful lot of play. Somewhere in the neighborhood of three inches. My next thought was maybe I had spaced out and forgotten to tighten the rear band in my reassembly rush. So I loosened the locknut and began to tighten up the adjuster. I would have bottomed the adjuster screw out in the lever and had to remove the locknut before I got any tension on the band. Something isn't right.

I know I was able to get tension on the low/reverse band last week when I assembled the transmission. Now I can't.

I am concerned that I have mixed and matched two incompatible systems. Here is a list of the mixed and matched parts:

Case- 1977 slant six 904
Output shaft and governor- 1977 slant six 904
Valve body, pistons, levers, accumulator- 1977 slant six 904
Rear band- new kevlar 1977 style single wrap band
Front pump- 1968 318 904
Front and rear clutches, gearset, overruning clutch gears- 1968 318 904

The only odd thing that occurred upon reassembling the transmission is that the valve body did not want to sit flush against the case (even though the valve body is the original for the case). The valve body did snug down once the valve body bolts were tighten, and it didn't take excessive force to do it.



I am going to go do some servo tests with air pressure to make sure the low/reverse servo is actuating and not stuck or cocked in its bore. But then I am stumped. Other than maybe a valve body problem.

Both the 68 and 77 transmissions are non lockup 904s. The 77 transmission is even the "simple" valve body style with no "1-2 shift control valve", so the valve bodies between the 77 and 68 transmission should be dang near identical. Maybe I will try swapping valve bodies if I find the low/reverse servo isn't working.

What goes "PING" and makes a transmission lose reverse?

Ow. I break more stuff when I get in a hurry...

It sounds like you broke a band. Ping is a common sound. It's possible the servo retainer didn't go in right.
The other would be a clip popping off, or shearing off the end of the input shaft. The Thrust Bearings in between the clutch packs are different for the slant and v8. They have three alignment tangs for the slant, and four for the V8. The pump shouldn't have gone back in if the thrusts were wrong.
I --think-- the input shaft is the same length, but I don't know.
Shearing the end off the input shaft would be a problem. By tightening the pump down with the shaft bottomed out against the inside of the gear set, tremendous pressure would be placed on the clip.

Not sure if I got the terminology right. Those thrust bearings shouldn't have anything to do with an alignment problem with the valve body.

Fopar?

CJ

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Part of Tyrde-Browne Racing

I'm going to throw a little more confusion into the mix; I'm told that's what I do best.

There are a lot of different levers. They are generally referred to by their ratio (3.2:1, 5:1, etc.). Which one was installed at the factory depends on the year and original application of the transmission, but they are all physically interchangeable and so unless you are completely certain of what transmission you're working on, if there's a possibility a different-than-original lever has been swapped in you can't go by the original year-and-application setting spec for the band adjustment.

And Reed, I don't know what Transmission gods your ancestors pissed off, or how, but…!!!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Valve body not setting down flush maybe the accumulator spring holding it up. Other than that I would second Ceej's thought the clip on the servo either broke or sliped off.


Richard

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Dan- I don't know. If I could find a way to appease them, I would.

I'll try and clear things up a bit.

The low/reverse lever is original to the case. I never even removed the tailshaft housing when I swapped guts, so the pin for the low/reverse lever was never removed from its bore.

I removed and replaced the guts of each transmission as a unit. I removed the entire slant six internal rotating assembly front the pump all the way back to the overrunning clutch, set it aide, and inserted the v-8 internal rotating assembly from the overrunning clutch to the front pump. All thrust washers and other internal parts stayed with their original application. The only original slant six parts still on/in the transmission are the case, servos and levers, tailshaft housing, output shaft, governor, parking sprag assembly, and the valve body.

Upon reassembly, the input shaft had a smidge of play. It didn't feel like it was forced tight against anything, but I don't really feel confident enough in my experience to recognize what is a "normal" feeling 904 input shaft. All my experience so far has been with worn out and/or malfunctioning transmissions.

More diagnostic info. I did the air pressure checks on the case. The kickdown and low/reverse servos engage fine. The front and rear clutches *appear* to engage fine, but I didn't get a very audible *thunk* from the transmission when they engaged. I tried to feel for a thunk and didn't feel much vibration either.

One odd result from the air pressure test is that there seemed to be air escaping from the "to torque converter" passage when I applied air to the "rear clutch apply" passage. However, it might have been air blowing past the rubber nozzle on the blowgun I was using and blowing the transmission fluid drips on the body of the trans. I did the test several times and couldn't determine if this was actually air coming back out of the torque converter port or "fugitive air" from the blowgun.

After getting positive results from the air pressure tests, I pulled the valve body and took it apart. No obviously blocked or damaged passages, all check valves present and in their correct places.

I readjusted the low/reverse band and it is tighter than it was before. The worrisome part was that to get the proper pre-load on the band I had to remove the holddown nut from the adjuster screw until I had backed the screw out four turns. Crap, I just read I should have backed it out 7 turns. Ugh, I'll fix it when I put the valve body back in.

WTF? Everything checks out like the transmission is supposed to work, but it didn't have reverse. This afternoon, the part throttle kickdown assembly I ordered from Pat Blais should arrive, so I will add the part throttle kickdown, reassemble, and try again.

If it doesn't work, I will go find a cliff and push this van off of it, in reverse.

EDIT: Thanks Fopar- I'll double check the accumulator spring. I really don't want to pull the transmisison to check for popped/busted clips, but if I have to, I will. My brother and I have gotten pulling the transmission down on his van to a 45 minute operation.

SECOND EDIT- There were no clips or band pieces in the pan when I pulled it. THe rear band still clamps around the rear drum when I move the lever by hand or when air pressure is applied to the "rear servo apply" port.

I suppose the upside to all this I am learning all about Chrysler automatic transmission and have lost my fear of working on them. Yay, I think.

Is it possible to replace the low/reverse band with the transmission in place? in other words, is there enough slack between the gearset and the case to sneak a new band by?

Alternatively, is it possible to check for a broken rear band with the transmission still in place?

Oh Great and Mighty Transmission Gods, hear me!

Reed has paid for his great-great Aunt's cousin's nephew's step brother's wife's transgressions with blood and tears of righteous wrenching!

Grant him the boon of thy forgiveness!

Hail Dexron! Give the poor guy a smooth shift to transmission Valhalla!

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Part of Tyrde-Browne Racing

I don't think so. You'd have to try it, but I don't think there's enough room.

CJ

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Part of Tyrde-Browne Racing

We'll see if that does the trick CeeJ!

UPDATE:

Low/reverse band did NOT break, all servo clips still in place and not broken.

I am going to reassemble and make sure that the accumulator spring wasn't holding the valve body away from the case and allowing fluid to go to wrong places. We'll see...

Fingers crossed!

(Have to. Just smashed the dickens out of a digit pulling studs out of a slant head. Nasty blood blister forming.)

After I quit cussing and hopping around on one foot, it's time for a beer. Yeah. That'll make it better.

CJ

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Ceej make that 3 beers, that should be your limit.

Richard

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Part of Tyrde-Browne Racing

Well, CeeJ's plea must have been the trick. The transmission now has reverse again. The only thing I changed was the adjustment of the rear band.

Here is what I think happened. In my rush to get the transmission reassembled (and due to my lack of experience) I made two errors involving the rear band: (a) I did not properly seat the band and strut assembly against the link and anchor assembly hanging from the low/reverse /ever pin, and (b) I adjusted the tension on the band to 72 inch pound and two turns out.

My belief s that the rear band assembly held together in light use during the week my brother drove the van, but when the transmission was asked to reverse the van up my step driveway the rear band assembly seated (the source of the PING) and all tension was released from the rear band, making the transmission slip out of reverse and lose reverse entirely.

I verified the rear band was properly installed, I readjusted the tension, and now the reverse works great. At some point I will install the part throttle kickdown (mail hasn't come yet), but, until then, the transmission is working fine.


Thanks for all the input guys. It is nice to have a good sounding board to bounce diagnoses off of.

I got cursed like that by yea olde gods of Torqueflight, I followed my
grandfather's advice and started taking up the old religion of New Process.
Unfortunately, the gods demand a sacrifice and I burn a clutch disc in offering more often than not...

Sounds like you got it working again, I'll keep my fingers crossed that does the trick.

Somehow that reminds me of that old Flintstones episode where Fred stubs his toe and starts dancing around like that and starts a new teen dance craze in Bedrock...somehow I don't see this one catching on with the neighbors...


-D.Idiot