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700R4 Overheating/Torque Converter Issue

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GalDemSuga

1/2 ton status
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Ok Folks

I have been dealing with my Trans spilling fluid into my Transfer Case for 3weeks. I believe it's because of overheating as a result of the torque converter not locking up. Here's my argument:

I remember see a TCC locked FLAG while running WinALDL with my truck in "Park" last week. I was attempting to tweak the timing and recall seeing that flag. I did some research and decided to see if the torque converter would lock up. I was driving on I-80 near Clearfield, PA and logged using WinALDL. I paid close attention to the RPMS and with the trans in OD @ 65 MPH I tapped the brake. I didnt see any increase in RPMS momentarily but rather it would drop as the Trans would downshift.

Are there any more ways to diagnose the torque converter? Could it possibly be the TCC?
 
Last edited:
GalDemSuga said:
Ok Folks

I have been dealing with my Trans spilling fluid into my Transfer Case for 3weeks. I believe it's because of overheating as a result of the torque converter not locking up. Here's my argument:

I remember see a TCC locked FLAG while running WinALDL with my truck in "Park" last week. I was attempting to tweak the timing and recall seeing that flag. I did some research and decided to see if the torque converter would lock up. I was driving on I-80 near Clearfield, PA and logged using WinALDL. I paid close attention to the RPMS and with the trans in OD @ 65 MPH I tapped the brake. I didnt see any increase in RPMS momentarily but rather it would drop as the Trans would downshift.

Are there any more ways to diagnose the torque converter? Could it possibly be the TCC?
Click to expand...

Trans fluid getting into the t-case is a bad t-case input seal.

When the trans downshifts the RPM's will go UP not DOWN.
 
4X4HIGH said:
Trans fluid getting into the t-case is a bad t-case input seal.

When the trans downshifts the RPM's will go UP not DOWN.
Click to expand...

I changed out the Transfer Case last Monday. I changed the input shaft seal and the Trans Adapter Oring. I did that test based on a post by you to determine if the toruqe converter was locking up. I got no RPM increase.
I also remember getting that TCC locked flag with the truck idling in PARK last Monday. I ran WinALDL after installing the new transfer case and tweaking the timing as the truck was running rich.
 
4X4, you need to read this thread before you consider what his problem is:
http://coloradok5.com/forums/showthread.php?t=265131
I have been trying to help him for a while, and we have exhausted most of the easy answers.
I am not as familiar with his setup as some of you folks are, and I admit I'm stumped.
Hope you can help.

J.
 
Glad to see you started a new thread. Surely someone here can figure it out.
Personally, I am not sure that you have an overheating problem. Or at least that an overheating problem is the cause of the fluid transfer.
Unless the heat is causing the fluid to get so thin that it is working past the seals. And I would expect you to start smelling burnt fluid if that were the case.

The main reason I was thinking heat was a pressure buildup. But I think you have pretty much ruled that out now.
Since you do not have the pressure line running into the transfer case, I am afraid that we are back to seals. Since you replaced them, I think it is going to be something more basic. Either a worn bearing that is letting the shaft wobble, or a bad place on the sealing surface that you did not see.

I mean, when you get down to it, short of some kind of Star Trek Transporter technology, the only path for fluid to get from the transmission to the transfer case is past those seals.

I still think that you could plug the transfer case vent, drill and tap the fill plug, and run a line from it to the transmission dip tube. Run the same fluid in both, and just let them circulate......

Heck, my 8N tractor uses the actual same oil for the transmission, rear end, and hydraulic fluid. No seals between any of them. You just pour 5 gallons in the transmission and it fill them all up.

J.
 
I just had my TCC solenoid replaced and after doing that I was really upset with myself. I just threw parts at the problem.
Here's the deal:
I replaced my ECM (month ago) and i just replaced the transfer case. The VSS is reading 20 mph less that when compared with my GPS. I know the GPS is accurate. Now the ECM is what tells the TCC to lock or unlock based upon my speed. I believe it to be over 35MPH. It seems clear that the TCC solenoid was malfunctioning but why? Last night I was getting the TCC locked flag with the truck idling in PARK. Now if the TCC was truly locked then the motor should have stalled and died, but it continued to idle just fine. I've called the nearest Autozone and had them order an ECM to replace this one thats still under warranty. I will swap it out at the part store tomorow. I dont know why the VSS is reading so far off. I mean 70 MPH on my GPS is 50 MPH on my speedometer.
 
I did not see he had another thread about a problem. The ONLY thing that will cause fluid to transfer from the trans to the t-case is a bad t-case input seal OR an incorrectly installed one.

To the OP, what brand and part number seal did you install? The reason i ask is because if you get one from a parts store it requires (2) seals to be installed back to back opposite of each other as they are only single lip seals whereas the original seal is a single double lip seal. The factory seal is about 5/8" wide and the store bought seals are about 5/16" wide. There must be a tension spring on the seal visible from the outside to seal fluid from the trans into the t-case and a tension spring on the seal on the inside of the t-case to seal fluid transfer from the t-case to the trans.
 
Well, of course, the normal reason for a speedo to read slow is bigger tires. I'm sure you have considered that. Besides, for it to read 20mph slow, you would need a ladder to get in and out. Did you have the GPS hooked up with the old ECM?
Plus is there not a way to program some of those to compensate for tire sizes? Maybe it just has the wrong program.
I don't work on those that much, and I just don't remember right off the top of my head.

J.
 
Fordum said:
Glad to see you started a new thread. Surely someone here can figure it out.
Personally, I am not sure that you have an overheating problem. Or at least that an overheating problem is the cause of the fluid transfer.
Unless the heat is causing the fluid to get so thin that it is working past the seals. And I would expect you to start smelling burnt fluid if that were the case.

The main reason I was thinking heat was a pressure buildup. But I think you have pretty much ruled that out now.
Since you do not have the pressure line running into the transfer case, I am afraid that we are back to seals. Since you replaced them, I think it is going to be something more basic. Either a worn bearing that is letting the shaft wobble, or a bad place on the sealing surface that you did not see.

I mean, when you get down to it, short of some kind of Star Trek Transporter technology, the only path for fluid to get from the transmission to the transfer case is past those seals.

I still think that you could plug the transfer case vent, drill and tap the fill plug, and run a line from it to the transmission dip tube. Run the same fluid in both, and just let them circulate......

Heck, my 8N tractor uses the actual same oil for the transmission, rear end, and hydraulic fluid. No seals between any of them. You just pour 5 gallons in the transmission and it fill them all up.

J.
Click to expand...

J
As it relates to the seals, its two different transfer cases and still the same issue. I cant prove its overheating but i'm only losing fluid to the transfer case. No fluid is going out the tranny vent tube.

Despite all this the trans works flawlessly. I just had the fluid changed and it was redish brown. It didnt smell or look burnt.
 
4X4HIGH said:
I did not see he had another thread about a problem. The ONLY thing that will cause fluid to transfer from the trans to the t-case is a bad t-case input seal OR an incorrectly installed one.

To the OP, what brand and part number seal did you install? The reason i ask is because if you get one from a parts store it requires (2) seals to be installed back to back opposite of each other as they are only single lip seals whereas the original seal is a single double lip seal. The factory seal is about 5/8" wide and the store bought seals are about 5/16" wide. There must be a tension spring on the seal visible from the outside to seal fluid from the trans into the t-case and a tension spring on the seal on the inside of the t-case to seal fluid transfer from the t-case to the trans.
Click to expand...

I got a National seal, its double lipped just like the seal that I removed from the transfer case. I made sure to get the correct seal. It matched the ones that were on both transfer cases.
 
What is the part number of the seal. I want to look up the specs on it. I replaced the input seal on my NP241 as well with a National seal and it required (2) seals.
 
GalDemSuga said:
Part # 710928 @ Advanceauto/Autozone
Click to expand...

Ok, i just took a look and the 710928 IS a double lip seal and the 3173 is a single lip seal and requires (2).

In this case either the seal got damaged when installing it (either got bent or distorted in some way) OR one or both of the tension springs got damaged or came off. The other thing that could be a problem like was already said is if there was a nick or gouge on the input shaft that you did not see that is in the seal area.
 
4X4HIGH said:
Ok, i just took a look and the 710928 IS a double lip seal and the 3173 is a single lip seal and requires (2).

In this case either the seal got damaged when installing it (either got bent or distorted in some way) OR one or both of the tension springs got damaged or came off. The other thing that could be a problem like was already said is if there was a nick or gouge on the input shaft that you did not see that is in the seal area.
Click to expand...

scott
I assure you that isnt the issue. Its two different transfer cases with the same seal and leak issue. I installed the new seals using my front spindle nut socket. It fits over the input shat and upper section of the seal. They weren't damaged. The seal housings are in great shape too.

What about my theory that excessive heat could be forcing the fluid into transfer case because of the converter not locking up. Remember that I'm driving on the interstate @ 70+ mph for long periods. Its all hills here.
 
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