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Trans Woes 4R100 7.3


Master Junk Tech
So my poor plow truck trans has not been nice to me. Sometimes it doesnt shift into 3rd. The trans does not slip. I have been plowing for 10+ years now and have never blown a trans. I know my mystery 216k F350 that I have only had for a few months now it could be the trans. I did service the trans 2 times since I have had it. When it is cold it shifts great. Warms up and then 3rd sometimes shifts and sometimes doesnt. When It doesnt the computer does command it to shift. So I did some research and called my local trans guy that has done some work for me in the past. Says its a common issue for the 2-3 shift valve to get stuck in the valve body. So I ordered an updated billet shift valve, solenoid pack, and a Transgo HD2 Tugger shift kit, and a .500 line mod valve.

Lets hope that I do not have to put a trans in this truck. If I do im going to have to keep it longer then id like too.
I was once told to consider the 4R100 behind the 7.3 as 'the fuseable link' in the drivetrain.... :rolleyes:


Master Junk Tech
I have changed a few at my job.....really dont wanna change this one lol. Rather not sink money into a truck that really isnt worth it haha
I've seen a few do exactly what yours is doing, and two of those who took my suggestion had success: Complete flush, change out the valve body and put it back together clean. The extras you've added can only help, IMO.
The ones who didn't do it wound up swapping in a used trans... To me, that's like taking a beating and asking for another one!
Good luck with it, and keep the shiny side up!


La Vergne, TN
The 4R100 is thought of same way as the E4OD were.. (Same trans just updated)..

Weak by some.. Loved by others..
But really in mine and many others experience they're strong as hell. UNLESS abused and not have been serviced like they should. They are very sensetive to servicing.


Master Junk Tech
The 1 is my V10 has been good, I have serviced it like 8 times in like 10k hahaha. The diesel has had more plow frames installed then ive had plow trucks.

I finished all the work. The only parts of the shift kit I did not install was the torq converter upgrades as the trans is still in it, and I didnt drop the separator plate to drill the holes bigger. I didnt have the gaskets and didnt want to take the chance of having to have it apart for longer then I wanted with no pan on it. Rain all day today.

I ordered the TransGo 4R100 HD2 Tugger Kit. New 2-3 shift valve, and .500 Line Mod Valve, and a reman solenoid pack. So the Trans Shifts good, but then shifts bad, I think its just done lol. Ill see what I feel like doing. My trans guy said 1000 to rebuild.......

I would have taken more pics, but I was covered in trans fluid lol

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