transmission mechanics question

[another Todd]

I have a motorhome (96 Ford 460 cu in E4OD trans with gear venders overdrive)that I use to go to the desert and tow about a 8000 lb trailer. For the past 4 years since I installed a temp guage, which is just before the first cooler, the oil temp pulling up the mountains has alway been about 180F. Coasting down hill raises the temp to about 210-220 briefly as the torque converter unlocks and heat builds updue to slippage in converter (normal). This weekend coming back from the desert the oil temp steadily climbed to 220 going up hills (40F higher than normal) and ocasionally hit 240F. I use Amsoil synthetic, so I am not woried about the fluid, but why is the temp climbing now? The converter was locking up, I could see the RPM drop after a shift and then drop again 2 seconds later when the converter locked as normal. But the temp kept climbing. Are the clutches slipping slightly and causing the heat? If so, what do I do about it? Any other ideas on the cause of sudden increase in temp? Water temp stayed normal. There was a strong "oil" odor when I got home but no leaks. Thanks.

Edited by another Todd (11/06/07 11:52 PM)

 

[unDummy]

How old is the ATF? filter? temp sender? gauge?

You need to verify the accuracy of your gauge/sender. They don't last forever.

If it is slippage, the transmission is all done.

You should also check for ATF flow through the coolers. Make sure that they aren't clogged internally(blow some air through them), and that the outside of the ATF cooler isn't packed with leaves, dead animals.....

 

[Gary Allan]

If it's slippage, shouldn't the PCM/ECM ..or even the TCM set some code to warn that the engine rpms and the VSS output don't match?

We'll assume that the level was normal.

Do you have any auxiliary filtration on this, Todd?

I'd say that, aside from any electronic diagnosis, a pressure test is in order.

I'll second undummy's recommendation for cooler flow. You might just do a preemptive solvent cleaning of the cooler (carb/tb cleaner with lines off - chased with air).

 

[another Todd]

The amsoil fluid in it has about 10000 miles, and maybe 4 years. The exterior of the coolers is clean. I do have a aux. spin on filter, which I change every year (due to be changed this weekend). The fluid is clean. The guage is about 4 years old and is a high quality Auto Meter Cobalt series. The temp. sending unit is on the filter housing before the coolers so I would expect sump temps to be much cooler than the temp guage reading. I will put my temp. gun on it next time to verify temp. Cleaning the coolers could be an idea, but the fluid has never been burnt or dirty and I cannot imagine the coolers plugging up. I have only seen that before when a transmission has gone bad and sent a bunch of garbage through--not the case here. When I change the filter this weekend I'll blow some air and maybe cleaner through to check.

Un dummy, why do you say if it's slippage it's done. If it builds heat (and I am not sure about this one I didn't specificly check)in third (direct drive)nothing could be slipping except the torque converter right? So if heat still builds, and it's not the coolers, couldn't I replace the torque converter? If the internal clutches are slipping, could I use a fluid with a little more bite such as type F? or is it dexron that has more bite---I forget.

 

[unDummy]

Because of the cause/effect of heat created slippage and knowing where it is coming from. If its the TC, what is it shedding into the transmission? Their is a cascading effect when something goes wrong in a transmission.

Hope for a defective temp sender. I find temp senders, even with name brand gauges, fail OFTEN.

When you replace the filter, cut open the old one which should help answer some questions.

If there is a sudden 40f increase in typical temps, then something failed. And, when something fails, it'll cause other issues.

Any mods?

 

[Gary Allan]

One quick thought that's poking through from the fog in my head ...

..is this one of the heavy duty automatics by Ford that uses a relief mechanism for cooler flow? I seem to recall that they have a spring poppet relief to regulate cooling via viscosity. We had this discusion in the bypass filter forum when one diesel accessory vendor asserted in his ad that you would get a light on the dash (on newer models) when the filter was plugged. He asserted that it wasn't reduced flow ..just higher than normal pressure. 1040 Wreckerman correct the false notion and linked to a site that showed the regulating mechanism. It's much like the older 80's Ford oil cooler regulation ..which was just a spring/ball setup. If the spring is shot or the ball scored ..

undummy himself recommended this page

Read what 1040 Wreckerman has to say.

 

[another Todd]

Gary, I don't believe mine has the cooler bypass shown. But I will check.

 

[Gary Allan]

It would be nice if yours does. It would 100% fit the symptoms if it was defective. No loss of service ...just unexplained higher temps due to no cooling.

 

[another Todd]

Gary, sadly no, I do not have a bango fitting with a bypass tube on this trans. I was hoping you were on to something! Tomorrow I will change the filter and run a can of berrymans backwards through the coolers and see how clean it comes out. I will also cut open the filter and see whats in it. Then next weekend I will trek to the desert again and see how it behaves. Fingers crossed.

 

[JustinH]

You need a bigger cooler sir.

Especially in the desert, towing all that load.

Something along the lines of this.

http://www.bulkpart.com/Merchant2/mercha...Product_Count=4

I agree with the above, buy a can of koolerklean, and take the hardlines off and clean them.

I have seen them totally clogged with clutch material.

 

[another Todd]

Do not know where my posts went so I will repost.
Justin, I have been running this setup for about 4 years and transmission temp has NEVER been an issue, probably still isn't at 220 with the Amsoil fluid but that is 40 degrees higher than the previous 4 years. I have two coolers already, the radiator one and one like the one in your link, but a little smaller.

Sunday I changed the spin on filter, and flushed the coolers, they were clean. I cut open the filter and there was no visable clutch material. When I went to reinstall the return line at the trans. I noticed the adapter had a check valve in it. The ball moved freely. There were no other lines coming away from that adapter for any kind of bypass, but I believe a bypass would have been on the output side anyhow. I will run to the desert again this weekend and see, but undummy might be on to something (bad guage or sender). I will check the external filter temp against the guage with my raytek temp. gun when I get to the desert. The temp. sending unit is in the filter housing, before the coolers.

 

[another Todd]

Went to the desert and checked temps with the raytek temp gun, there seems to be about a 15 degree difference (gun registering cooler than guage). Everything may be OK. I will change the temp sending unit and/or the guage to see if it settles down. I do suspect the guage/sending unit now because the higher the temp on the guage goes, the faster it climbs. It never climbed that fast before and no matter what could be wrong with the transmission, I cannot believe the temp could climb as fast as it was when it got over 200.