I have a 04 F250 with a 5.4 and a 4R100 trans and once in a wile when its warm it will shift hard from 2 to 3 and sometimes from 3 to 4. When it does the hard 3 to 4 it actually makes the belt chirp from the sudden drop in RPM.

I've seen plenty of 1-2 hard shifts on 4R70w's with sticking accumulators or broken accumulator springs but this is new to me on a 4r100 and I'm not familiar with the 4R100 inner working's.

Anybody have any idea's?

 

all i can say is theres allot of us 5.4 guys on here that are having this same issue. Including me! my truck has been doing this for almost four years, i flush the fluid ever two years, Ive checked the shift springs, changed the shift springs, changed the separator plate gaskets ALL with no luck. Ive recently had a pressure check done and the shop said that they all are all well within spec, there only remark "well you have 105k and the clutches are probally getting worn out and the trans is going to need to be rebuilt soon". I find this odd since its been this way for four years but I'm no trans mechanic

 

i personally think its electronic issues with the 5.4 and 4r100 combo. Cols the truck is fine but when its warmed up it starts to act up. Some days i drive the truck like its a Boss Mustang and it shifts beautiful! Then the next day ill drive like my grandfather and it acts up again? Ive learned to adjust my shift pressures with my tuner and am ok with the shifts for now, im just waiting for the trans to blow if it ever does and then im just gonna have BTS build me a "real" truck trans

 

My original trans went bad, (hub broke internally) and I bought this trans from a JY. It has a 3 year parts and labor warranty and had 77,000 miles on it when I got it.

I was hoping it was something simple because I really don't feel like pulling this trans again.

 

it did this as soon as you installed it? I bought my truck brand new and have always flushed the trans fluid ever two years since new. And mine did this at around 65k ish too? Another member on here PM's me and has the same issues and his truck has just about 80k on it

 

but then again the 5.4 auto trans has fewer clutches, and i think smaller planetary gear's then the V10 and 7.3 diesel transmissions. So maybe this is the main problem so many of use are getting these weird harsh shifts

 

Didn't notice it immediately, but I wasn't really driving the truck that much. Due to the hurricane I've been using the hell out of it and noticed this problem.

I work in Neptune NJ in the AM and Newark NJ at night and there is trees and poles down everywhere. A lowered Thunderbird is not the smartest choice with those road conditions so I've been putting 97 miles a day on my truck.

I'm glad to see nobody had a catastrophic failure because of this problem.

 

like i said its been four years and when i drop the trans pan i never have any metal on the magnet and when i cut the filter open i never see metal or anything. Ive changed the shift valves and springs but never the accumulator body because the valves always fall right out and are never stuck. I might just buy a rebuilt valve body from the local trans shop this winter when i flush it again and see if the rebuilt valve body fixes the problem. Its only like 80 bucks for it so ahh its just money

 

Where can you get a reman VB for $80.00?

 

no one ever notices it when their in my truck BUT i do ever time it starts to get that harsh shift. Everyone thinks its normal because of my tuner....

 

ebay sells them but the shop up from my house told me i could get it for like 80 bucks when i was there and had them do the pressure tests on the trans

 

heres one that they install all new springs for whatever you own, V8, V10 or diesel

4R100 Valve Body Assembly 4 PC Set | eBay