Help! Replaced transmission... same problem

[manticore33]

Previously, I had an issue where my 96' Explorer (4r55e 4x4) would not go into any gears, but park would work. Many months later, I disconnected one of the hard transmission cooler lines and had no fluid flow. It was determine it probably was the transmission pump. I check for flow at the upper hard line that runs into the radiator.

Fast forward a many months later, and I purchases a certified good used transmission. I can't actually guarantee it is a working transmission, but I was told it was from a live donor.

Well, I put this new-to-me transmission in and still have no gears but park. I changed the fluid filter, dumped and prefilled the TQ. Filled the trans with fluid. I used whatever shift motor and solenoids that came on the used transmission. I still have no flow through the transcooler, however, this trans shot fluid out of the vent tube with the truck idling.

I am lost, frustrated, agrivated, and got speeding ticket while getting transfluid (I was tired and not paying attention). Any ideas would be greatly appreciated.

 

[Jones]

I don't know a lot about transmissions, but a couple things occured to me when reading your post. If I'm wrong hopefully somone will correct me. First, why did the transmission expel from the vent? One reason could be overheating. If neither tranny pumped through the line, is it possible that the line is clogged? You can test this by setting up a temporary flexible loop bypassing your hard lines and cooler and going right back into the transmission. A clogged pressure line would explain neither transmission working and neither one pumping to the cooler. It would also explain the overheating. Hopefully the new transmission didn't get so hot as to damage it. If you find that it is a line problem, you need to be very careful that the contaminated fluid in your lines and cooler does not go back into your tranny, that you expel all of the old fluid (like 14 qts. or something) that your lines and cooler are new or perfectly clean and if you don't replace them maybe you should replace your filter and put a magnet in the pan. I hope I'm not leading you in the wrong direction. Good Luck.

 

[BrooklynBay]

Check your hydraulic pressure on the transmission with a 0-300 PSI gauge. There is a plug on the transmission which could be romoved just for this purpose.

 

[BrooklynBay]

Check this link: http://www.explorerforum.com/forums/showthread.php?t=117998. It explains how to use a transmission pressure gauge.

 

[manticore33]

Well, I disconnected all of the hardlines and shot air through it. No clogs in the line. Likewise, I shot air through the transmission cooler inside the radiator, again, no clogs. I will look into getting my hands on a transmission pressure gauge. Although, I am really starting to believe I got a bum transmission. Unfortunately, working fulltime and being in a master's program left me with little time and I exceeded my 30 day guarantee. Just my luck... I'll own another dead transmission....

I did replace the filter and dump out as much old transmission fluid as possible. Is there something else I should consider? When I was filling the transmission up, it did overflow the dipstick at ~7qts.

Sorry, I am a bit wore out about the whole ordeal. I am very seriously contemplating selling it and taking a major loss. Or coverting to a 5-sp. For what it is worth, how difficult is it to change the transmission fluid pump?

 

[BrooklynBay]

You have to remove the front bell housing where the torque converter is located. The pump is located inside of the transmission behind that area. A lack of hydraulic pressure could be either a pump, or valve body related issue.

 

[manticore33]

Q

In your personal opinion, which would you lean more towards? Valve body or the pump? I have no fluid flow. Is it possible that maybe I did not connect a sensor and that is the problem? Or is it a "abolsute always" that the transmission will cycle fluid through the coolant system even if the electronic components are not working? Edit: Or is it possible I did not get the TQ seated properly? I rotated it until it "went" in further and seemed to "lock in."

Thanks,

Brett

 

[Jones]

I am clearly out of my depth here. You are going to have to rely on some of the transmission "heavies" for actual info. But again, a couple of thoughts.
1]What toruqe converter are you using? If you are using the one off of the old tranny, then, well. And I think that junkyard converters have been mercilessly maligned for good reason in this group and elsewhere. I wouldn't think that you could get the case to bolt up properly if you hadn't seated the converter, but I could be wrong.
2} Again, I don't know what I'm talking about but that has never stopped me from talking. So I was thinking that with all of the hundreds of things that can go wrong with a transmission it seems odd that two units have exactly the same problem in the same truck. Certainly it could happen, but it seems to me at least as likely that the problem is in the truck as in both of the transmissions. As per the sensors I dunno; I suppose it's possible for the vb to stop circulation for whatever reason and I suppose this could be controlled by a sensor/solenoid or whatever though I would tend to doubt it. Another question for the hydraulic wise men. What happened to your truck before it quit working? Was there decreasing performance, leaking, any weird stuff? Or did it run fabulously and then quit? If you are using the old TC and it was beat, I imagine it would make your new tranny act just like your old one, and TCs tend to croak in a pattern. If there was something wrong with where the input shaft of the tranny takes off from the motor (Or whatever crazy arrangement they have in there) again, it would cause lack of pressure. And while I don't know jack about transmissions, I do know that without pressure you are without a transmission. Except for Park. Good luck to you and your tranny (and to me and mine).

 

[Jones]

PS. Did you look at your crank spacer? Could it have been so mutilated so as to cause chronic TC problems?

 

[BrooklynBay]

The electronic valve bodies on the 4R, and 5R have a temperature sensor on the internal harness. Your valve body cuts the flow of ATF to your external cooler when the ATF's temperature is below a certain temperature. Some of the rebuild kits have a modification for bypassing this. I'm not sure of the exact term, but it might be something like thermostatic lockout, or something similar. Before making assumptions about why there is no pressure, connect a pressure gauge onto the transmission. There might be some pressure, but not enough to engage any of the pistons, or clutch packs. Did you ever check out your transfer case? If you have the same problems with both transmissions, it might be the transfer case.

 

[manticore33]

See I did not know that (about the temperature sensor). I figured the t-case was ok due to park working and the fact I could rotate the output, front and rear, side of the t-case with no binding. Are there better ways to test t-case functionality?

 

[BrooklynBay]

Did you check the sticky about the transfer case shift motor rebuild? It mentions some information about disengaging the shift motor, and turning it manually. Do you hear the motor turn when you change the settings? Did you ever replace the fluid inside of it? If you see any metal shavings in the fluid, it probably means that it has some internal damage. Look at WWW.Drivetrain.Com for a diagram of your transfer case.

 

[manticore33]

I will review the sticky and investigate further. I have changed the fluid (twice now) and never had metal shavings. I drained it before yanking it off of the transmission.

Thank you for your assistance, I greatly appreciate it.