4R100 Problems
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New User
Joined: May 2016
Posts: 19
Likes: 0
From: Frederick, MD
4R100 Problems
Problems with my 2001 F250 4r100 transmission. Transmission will only shift to 2nd gear when throttle is feathered at @2500 rpm. All other gears shift perfectly. This problem is consistent.
Any help will be appreciated.
Thanks.
Any help will be appreciated.
Thanks.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,732
Likes: 2,661
From: SE Florida
It's time for a rebuild.
The 2001 4R100 behind the 7.3L had a new type of one way clutch called a mechanical diode. When (not if) it fails you will get the exact symptom you have described. The only solution is to rebuild the trans and replace it. There are kits available to replace the mechanical diode with the older (and newer) sprag type one way clutch.
The 2001 4R100 behind the 7.3L had a new type of one way clutch called a mechanical diode. When (not if) it fails you will get the exact symptom you have described. The only solution is to rebuild the trans and replace it. There are kits available to replace the mechanical diode with the older (and newer) sprag type one way clutch.
Post Fiend
Joined: Mar 2002
Posts: 19,402
Likes: 38
From: Bonita Springs FL
You probably shouldn't attempt to rebuild a 4R100 if you've never done any transmission work before. There are a whole host of upgrades that should be included in the rebuild.
The quality of rebuilds on this transmission vary widely. If you take it to your local aamco or random transmission shop, you may or may not have a lot of problems with it.
I do almost all of my own work and I wouldn't rebuild mine. It's going to John Wood later this year.
The quality of rebuilds on this transmission vary widely. If you take it to your local aamco or random transmission shop, you may or may not have a lot of problems with it.
I do almost all of my own work and I wouldn't rebuild mine. It's going to John Wood later this year.
Senior User
Joined: Oct 2016
Posts: 215
Likes: 1
From: Near Rockford Illinois
Does that shop in Joliet IL know how to build a high quality 4R100 ? I have a little over 282,000 on the truck and my trans seems like it is slipping some times.
Thank you,
BBD
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,732
Likes: 2,661
From: SE Florida
Yes, I believe they do. They don't do a lot of modifications like the high dollar shops, but I'm sure they can get you a high quality trans.
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Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,732
Likes: 2,661
From: SE Florida
Some people can, some cannot. I really don't know your skill level. I don't mean anything derogatory by that, I just don't know if you can or cannot do this. It's not a simple job, but it isn't rocket science, either. It requires a really good shop manual. Automatic Transmissions Service Group has a good manual.
All the friction material should be changed. There is one band and several clutches. All seals should also be changed. A master rebuild kit will have everything that needs to be changed. You'll also need the kit to replace the mechanical diode with a sprag clutch.
All the friction material should be changed. There is one band and several clutches. All seals should also be changed. A master rebuild kit will have everything that needs to be changed. You'll also need the kit to replace the mechanical diode with a sprag clutch.
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Senior User
Joined: Oct 2016
Posts: 215
Likes: 1
From: Near Rockford Illinois
Mark,
Thank you again for all of your help and the lead in Joliet.
In the transmission world, I have heard the "updates and modifications" terms used.
BBD
Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 25
From: Damon (South East Texas)
Some people can, some cannot. I really don't know your skill level. I don't mean anything derogatory by that, I just don't know if you can or cannot do this. It's not a simple job, but it isn't rocket science, either. It requires a really good shop manual. Automatic Transmissions Service Group has a good manual.
All the friction material should be changed. There is one band and several clutches. All seals should also be changed. A master rebuild kit will have everything that needs to be changed. You'll also need the kit to replace the mechanical diode with a sprag clutch.
All the friction material should be changed. There is one band and several clutches. All seals should also be changed. A master rebuild kit will have everything that needs to be changed. You'll also need the kit to replace the mechanical diode with a sprag clutch.
The retrofit of parts, for the mechanical diode replacement, is fairly simple and is not too costly to do. It does require you to change the proper clutch pack that companions it. Most kits only include these frictions nowadays, as it is no longer serviced.
Hotshot
Joined: May 2005
Posts: 13,484
Likes: 42
From: Stevens Point, WI
Its diode season!
Here is my diode fun thread I just started. My first ever auto trans attempt. Only thing I can say about it so far, ALLOT of reading!
https://www.ford-trucks.com/forums/1...diode-fun.html
Here is my diode fun thread I just started. My first ever auto trans attempt. Only thing I can say about it so far, ALLOT of reading!
https://www.ford-trucks.com/forums/1...diode-fun.html
5th Gear
Joined: Feb 2021
Posts: 5
Likes: 0
I apologize if this is the not the best thread to ask this question on, I am new here. I have an 02 F250 with the 7.3 and 4R100 combo and I have the exact same symptom in my transmission except it is with 3rd gear. I am guessing I will probably need to rebuild it or replace it after reading this and some other threads.
Last edited by Y2KW57; Feb 25, 2021 at 02:41 PM. Reason: Removed link to "mystrikingly(dot)com"
5th Wheeling
Joined: Sep 2022
Posts: 30
Likes: 2
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