Ford 4R100 Transmission Question/Problem/Need Advice

[winnie32v]

I have a 2001 Winnebago Adventurer 32V built on a 2000 Ford F53 Chassis with a V-10 and 4R100 Transmission.
It has 45,000 miles on the unit.
I bought this motorhome about 2 years ago at 41,000 mi.
I changed all fluids.
I drained the 4R100 torque converter and dropped the pan and replaced all of the fluid with new Dex/Merc transmission fluid.

This year while returning from Florida to Pa. I noticed a "transmission shudder" when the transmission downshifted to 3rd at approx 3,000 RPM.
When the "rumble strip chatter" started, I would just let off of the gas about 1/8" and the chatter would go away.....when I gave it a little more gas, the chatter resumed.
Sounds like the transmission clutches.

When the unit downshifted to the next lower gear...at appx 4000 RPM, there was no chatter.

NOW, I have found out that the 'Dual Purpose' Dex/Merc is NOT supposed to be used to replace the original Mercon transmission fluid.
SO........I have also found out that the "Old" Mercon original fluid can be replaced with the better synthetic Mercon V oil.

My task this summer is to drain the torque converter (yes, this year has the drain plug), the pan AND gently blow out the cooler tube (15 psi) and replace the better fluid with Mercon V fluid.

So a couple of questions:
1. Did I do any possible damage to the transmission using the Dex/Merc fluid?
2. From anyone's experience, will the Mercon V cure the clutch shudder problem?

Also, I should add that I went from a 2000 Jeep Wrangler soft top as a tow vehicle to a 2008 Jeep Grand Cherokee....maybe an additional 1500 - 2000 lbs tow.
I DID notice the extra weight when I was going up the hills.
This probably amplified the transmission issue and brought it to my attention !!!!!!

The engine runs great and everything else is running fine.

Please advise from your experience with the 4R100 transmission and let me know if I'm doing the right things to get me back to Florida this winter.....OR....anything else that might refer to this situation.

Thank you for your time and advice.
Regards,
Paul

[Mark Kovalsky]

The Dex/Merc fluid WILL NOT harm your transmission. It can be replaced with MERCON V, which is only synthetic if you buy synthetic. You can also buy MERCON V as conventional or synthetic blend. It's your choice.

Changing to MERCON V will not fix your issue. You are looking too far back in the motorhome. The symptoms you have described are those of a low grade engine misfire. You have one or more spark plugs that are getting old, or the ignition coil boots have developed cracks, or one or more coils are getting weak.

[jamesrxx951]

Either it may be a misfire as Mark described or it could be torque converter shudder on release when it downshifts. When this transmission downshifts the OD clutch releases and nothing else changes. So there should not be any shudder from a clutch because no clutch applies from 4th to 3rd. However it may need to be determined if the torque converter is releasing at the time of the shudder. I have diagnosed many misfire concerns that were thought to be transmission issues and many torque converter shudders that were thought to be misfires. A scan tool like what a Ford dealer uses (IDS) is a very good tool to determine if the shudder is engine or transmission related. My money is on a misfire though.

[C-Leigh Racing]

Maybe the draining of the torque converter, when the fluid was changed has something to do with it, because the only way it could fill back up, is with the engine running & trans pump filling it.
Just a thought.
Neil

[Mark Kovalsky]

Originally Posted by C-Leigh Racing

Maybe the draining of the torque converter, when the fluid was changed has something to do with it, because the only way it could fill back up, is with the engine running & trans pump filling it.
Just a thought.
Neil

Do you have a theory on how that's even possible, or are you throwing out wild guesses?

If the vehicle moves under it's own power then the torque converter has filled. If it didn't fill it won't transmit torque and the vehicle won't move.

[C-Leigh Racing]

You did see my first word, where I said maybe, which pretty much ment I'm not 100% sure, because I dont know how the 4R100 transmissions torque converter is made on the inside, but any time you run something dry, theres no telling what could happen between the time it is filling back up with fluid.
I just added that as an idea.

Since your a former Ford automatic transmission engineer, wouldnt it have been better, by what you know about Ford automatic transmissions, to add your input as what the problem might be with the members transmission, rather than trying to degrade me for the simple idea in a reply I entered.

I mean like really, help the member out with his problem & leave me alone.
Neil

[Mark Kovalsky]

Is there really any shame in not answering an open thread such as this if you don't know the answer? There is no good that comes from guesses of people that don't even know how the system operates. Why send the person with a problem on a wild goose chase? If you don't know how it works, just read the thread instead of leading someone astray.

And if you would have read my first post in this thread I did tell him what I believe is wrong with his vehicle. And that comes from many years of experience with this powertrain.

[garykk]

:

[Arizona]

We also have a 2001 adventurer that we bought 2 years ago with 35000 on it. I changed the fluid, drained the converter, changed the filter, and filled with dex/merc fluid. Five thousand miles later towing the tracker and no slippage. Try changing your fuel filter first. Only $8.
Good luck

[winnie32v]

Update:
After all considerations it turned out to be a bad tank of gas that we got at our last fill-up in Va. before returning to Pa.
We filled up with 93 octane (45 gal of a 75 gal tank) and the unit now runs flawlessly.
Went up two of the biggest hills in the area with the Jeep in tow as a test run.

Now that we look back, all of the symptoms make sense.

Thanks for all of your advice.
Regards,
Paul