Just got my 4r100 Rebuilt for heavy towing with a billet torque converter. The mechanic Said there was 3 different settings for the transmission. 1- Towing and fleet, 2-regular driving, 3- high performance( go fast trucks). Mine is set at 1. He informed me that it shifts very hard for towing and said this is normal since it will grab the clutch harder limiting slip and friction. Anyone have experience with this? He also said he rerouted oil inside the trans. to share with a different supply. Apparently the stock trans had the torque converter sharing a oil supply that wasn't sufficient which caused premature failure. The truck runs out to 2700 rpms 1st and 2nd gear when you stomp on it, but shifts hard even when taking it easy. please let me know what you guys think, thanks

 

All of the heavily modified transmissions that I've driven have shifted more firmly than stock. The firmness was more noticeable when trans fluid is cold. Depending on how the builder modified the trans, the shifts can be more aggressive when heavily loaded, which I don't really care for but some people do it that way. (ATS Diesel comes to mind....)

My daily driver has the Tugger kit....it's firmer than stock but not so bad that it's bothersome.

 

Yes , this seems pretty firm. almost uncomfortable, but i told him i wanted built very heavy duty for daily heavy loads. just seems a bit extreme

 

It is good to have a firmer shift, but not harsh. If is it harsh, he may have gone to aggressive with a shift kit or valve body work.

By "settings for the trans" do you mean it has a chip/tuner? That too could be the cause if the tunes are not setup correctly for the trans work that has been done.

 

Honestly im not sure about a tuner, it kind of sounded like that though. Just spent 3,000 for the rebuild, and not sure its right. Went with the guy that was a little more money since he said he has done quite a few of these, the 4r100's seem to be a common problem. Not sure what to do , as i know nothing about a heavy duty trans upgrade. Seems a little over the top though, just have no way to gauge it comparatively speaking

 

Sounds to me like he went over board with the valve body. I'd have him change it. You don't need hard shift for dd. Have him correct it to your liking. As long as the parts inside are done right you will have no problems.

 

It should shift softer. If there was/is tuning on the truck, this can cause issues with a modified valve body. If there is no tuning done, then the VB is likely set on kill. Shifting fast and firm is fine, harsh is not IMO.

 

Is he going to have to drop the tranny to adjust the valve body ?

 

No. Just drop the pan and filter, and it's right there.

 

Check the back of the PCM to see if there is a chip installed. It's behind your e-brake inside the cab.

Unfortunately, there are a lot of good trans builders out there who are just not good with the 4R100. They treat it just like every other trans they build. IMO, the best option for a normal guy not looking for big HP is the HD4R100 directly from your Ford Dealership. It runs right around $3000 and has a 3 year unlimited mileage warranty. Warranty is good at any Ford dealership nationwide.

 

Really wish i would have known that, i just paid 3,000 to rebuild mine

 

Yes, you are not the only one. I talk to guys all the time who pay $3000-$5000 for a rebuilt trans from a local shop. The shop claims it is "fully built" and "can handle 1000HP", but as soon as you give it more than 450HP it starts to show it's true colors.

The Ford HD4R100 can hold 425HP all day long. I'm sure it could do more, but 425HP is staying on the safe side.

 

Hopefully the problem is a tuner issue. If you find that, it's likely the reason for the harsh shifting and easily remedied. If not, the valve body needs to be reworked or replaced.

 

that trans has not got a valve body that can be adjusted, it shifts electrically. all shifts. it uses information from engine computer and makes decisions when to shift. if it has a larger clutch assembly in converter they turned up the flow to keep it from slipping, a after market trans controller may fix the problem, but by softening the shifts, you may cook the clutch's from the slipping.

 

Valve bodies are adjusted by enlarging some of the holes and different springs. So yes it can be done.