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Discussion Starter #1 (Edited)
I started my FSB and pulled it out of the garage to give the belly and motor a bath. I sprayed it all down with degreaser and hosed it down very thoroughly. After I started it back up to drive it dry. I put it into gear and nothing; no reverse, no drive movement at all, not even a nudge of movement. Has anyone heard of this? The linkage is fine and it has always shifted just fine until now.

I looked at some potential problems, one being the vacuum modulator. But no one mentioned fluid would come pouring out when removing it. Is that supposed to happen? I did have fluid in the vacuum line, bought a black stripped VM from Napa, replaced it, and no change.

I pulled the dip stick which showed the tranny having way too much fluid in it. There was fluid about 4" up on the dipstick. Is it possible the fluid drained out of the torque converter? How do I check if that happened and refill if need be?

I dropped the pan and there doesn't seen to be any debris or signs of struggle. There is a good amount of vacuum in the line, but I will testing how much tomorrow and the new part I put it. The little pin that sits in between, what does that do?

Is there something electrical I should be checking? I didn't see that in any previous breakdowns of issues like this. One step I know I should have taken is disconnect the battery, which I did not.

How does a spray down with a hose stop a tranny from working? Forgot to mention C6 tranny 3 speed (thanks dash_cam).

Any help greatly appreciated! Here she is in the north GA mountains.
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Yo Rhino766,
The vacuum modulator was bad because its diaphram ruptured and black stripped unit is correct.

Usually fluid flows from the C6 to the transfer case as described in "
Fluid Level Low, Low Transmission Fluid Level And Or Shift And Or Engagement Concerns TSB 97-12-13 for 87-96 Bronco & many others; "...transmission may have low fluid level and/or may have either a shift concern and/or an engagement concern. This may be caused by transmission fluid leaking from the transmission into the transfer case through the transfer case input seal. Replace the transfer case input seal..." read more
Source: by Ford

Any signs of water in the fluid? There is a vent on the top of the transmission that may have invited water in.

C6 Doesn’t Engage in Drive or Reverse:
  1. No control pressure.
  2. Low fluid level.
  3. Torque converter and/or front pump cavitated (no fluid or air in fluid).
  4. Torque converter improperly installed, doesn’t turn pump (listen for noise).
  5. Manual shift linkage between car and transmission improperly adjusted.
  6. Manual shift valve inside transmission pan not connected or stuck.
  7. Pressure relief valve (or valves) unseated or missing.
  8. Forward clutch pressure leak or improperly assembled (air check clutches by removing the valve body).
  9. Blocked filter.
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Discussion Starter #4
How do i make sure the torque converter has not "cavitated" and how common is that? What causes it? If the fluid was going into the transfer case the level would be low i imagine which was not the case here. Also, is at least 1 1/2 qts supposed to come dumping out when I pulled the modulator? A valve body inspection and new filter are happening tonight. Thanks!
 

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Given the sudden loss in drive i'd say you likely have a simple problem. I'm no expert on the C6 but IIRC the modulator controls shifting, but being bad shouldn't cause no movement at all. Given your lack of movement in any gear position, and how suddenly it came on, my money is that you have an issue with the shift linkage.

Also are you checking the fluid with the engine running? 99% of vehicles need to have the engine running with the trans in park or neutral to get a proper reading.
 

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Discussion Starter #7
To completely rule out the linkage I chalked all four wheels and was shifting from N to D from underneath. Engine was warm and reading on the dipstick was about 4" up on the stick. About 2 1/2" inches too high up on the stick. I'll keep poking at it. Thanks.
 

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High fluid level could mean the trans pump is not pumping fluid, which would also explain the lack of motion. Transmissions operate on hydraulic power. No pump= no pressure= no nothing.
Why it would suddenly stop working is beyond me. I did have a CX7 with a TC issue that seems to kill pressure halfway around the block but it makes tons of noise as well.
 

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Im shocked no one has mentioned, "is the transfer case in neutral? "

Is there any grinding noises when going back to park after going through the gears?
 

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Im shocked no one has mentioned, "is the transfer case in neutral? "

Is there any grinding noises when going back to park after going through the gears?
Would not be the first time I overlooked the obvious. Still doesn't explain being 4" overfull.
 

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Pull the return line, at the rubber hose isolator section after the cooler, and put a bucket under it. Crawl out and start the truck in PARK. Then move to NEUTRAL. Make sure the pump is pumping fluid in both gears and your lines/coolers aren't clogged. If not, there's the big issue. If it is pumping, then do as much troubleshooting from under the truck as possible, starting with vacuum checks and line pressure tests. After that, pull the pan and do some servo inspections. If you're comfortable with it and have an exploded diagram with torque specs, pull the valve body and inspect all the valves, pistons, and related bores. Make sure nothing is sticking, binding, or clogged. Hose everything off with brake cleaner (individual disassembled parts as well), install new VB gaskets, give everything a fresh fluid bath, and re-install. That way you, at least, know the VB is operating and you're only out some time, fluid, and gaskets. If that doesn't work, I would plan on pulling the trans. If you're not comfortable tearing into the VB, it's probably best to leave it to someone else.

Just my $0.02.
 

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Discussion Starter #12
Thanks for the input.

Can you guys tell me what the chances a C6 out of an 86 with a 351 will bolt up to my 351? I found one that looks rebuilt(pics). This lady said her husband passed and doesn't have much detailed info other that the truck it came out of. The only thing I see being a problem it has a plug where the selector shaft would come out of the housing you can see in the pic. I think I can pick this up for $500. Thoughts/problems that might come up?

After pulling the pan there were some very small metal specs caught by the filter and a very small amount of sentiment in the bottom of the pan. I installed a new filter and refilled it with nothing but the same problem. My next check was to pull the TC lines and see if fluid was moving so I'll do that next. Then I'll be pulling the valve body. At this point I think either one of those metal specs blocked one of the valves or the pump or converter are shot. On the bright side this thing is as simple as it gets imo. Oh and my rear end is shot and will need a rebuild too. Gonna have a new truck soon! lol.
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Discussion Starter #13
Oh and I did check the transfer case. Shifted it through high and low with no change.
 

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Thanks for the input.

Can you guys tell me what the chances a C6 out of an 86 with a 351 will bolt up to my 351? I found one that looks rebuilt(pics). This lady said her husband passed and doesn't have much detailed info other that the truck it came out of. The only thing I see being a problem it has a plug where the selector shaft would come out of the housing you can see in the pic. I think I can pick this up for $500. Thoughts/problems that might come up?

After pulling the pan there were some very small metal specs caught by the filter and a very small amount of sentiment in the bottom of the pan. I installed a new filter and refilled it with nothing but the same problem. My next check was to pull the TC lines and see if fluid was moving so I'll do that next. Then I'll be pulling the valve body. At this point I think either one of those metal specs blocked one of the valves or the pump or converter are shot. On the bright side this thing is as simple as it gets imo. Oh and my rear end is shot and will need a rebuild too. Gonna have a new truck soon! lol.
View attachment 163507 View attachment 163508
Welcome to the club! Redid the whole brake system as well as fuel system, my gf has been wanting to ride in my bronco for over a year now but something is always broken. Next thing you know my transmission or engine will give out lol.


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Oh and I did check the transfer case. Shifted it through high and low with no change.
Ok.... but was there any grinding noises when going back to park?

This is KEY INFORMATION.
 
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