I have a 2002 F-150 Supercab 4x4 with the 5.4L and the 7700 package. From reading through some posts I found out that with the 7700 package I got the 4R100 tranny in my truck. I am curious, what is the differences between these 2 trannys? Did I get a better tranny?

 

This is doubtful. Most F150's, including most of the newer 7700's got the 4R70 transmission. Check the transmission code on the door sticker on your truck. The letter under "TR" indicates which transmission you got. A "U" is the 4R70, an "E" is the 4R100. The only F150's that really got the 4R100 are low emissions versions sold in states like California. The 4R70 is not low emissions certified.

As for the differences? Size for one. The 4R100 is a much larger transmission physically. The 4R70 is also rated for 700 lb/ft of torque (70 x 10) whereas the 4R100 is rated for 1000 lb/ft of torque (100 x 10).

The 4R100 is a much stronger transmission. There are a ton of variations on the 4R100 (depending on whether it is in a regular F150, a Lightning, a diesel, or whether it has a power take off just to list a few).

The 4R70 can be built pretty strong, but the stock unit leaves a lot of room for improvement. The same can be said for the 4R100, but it starts out a lot stronger and can be built up further.

-Don

 

I had to run out to my truck to check. Under TR I have an "E". So I guess I have the 4R100?


What are its weaknesses and what can be done to improve it?

P.S. Thank you for your help!!!

 

Yes and that is very rare indeed. Almost the only way to find a 4R100 is in a low emissions version of the F150. You usually only see them in California, though perhaps they are sold in the NorthEast also.

As for what can be done to make them stronger? A lot. Do you need to? Probably not. Invest in a good transmission cooler and that is probably sufficient. Changing out clutches, adding additional plates, and changing the sprag just isn't worth it unless you plan on racing or doing some serious pulling. The 4R100 is just plain strong enough in stock form for most uses.

You can also change out the valve body to make it shift more firmly which will improve clutch life.

If you want to get a bullet proof transmission, then speak to Gregg Evans and get one of his Monster Box 4R100's. There just isn't a stronger transmission available. They run about $2100 or so plus a $1200 refundable core charge (last I checked). As you do not have a Lightning transmission there would be an additional $500 charge for the upgraded parts.

As I have said though, the 4R100 is plenty strong even in the basic configuration. Add a valve body and a transmission cooler and you should get very long life out of your clutches.

-Don

 

I have the 7700 plus I have the towing package. Because of that I know I allready have a transmission cooler. Are you suggesting that I need to upgrade the transmission cooler, or should I be fine with the factory one?

 

The factory transmission cooler is probably fine, but some people swear by aftermarket versions. The choice is yours. The valve body is still a good option though.

-Don

 

Shameless plug/free post
Unless you plan on doing some heavy racing, the one you have is a real good box, if you want an accumulator or an extra cooling unit to work in addition to the one you have, I make both, and make some pretty good parts if I do say so myself...

You can e-mail me for more specific information, I'm glad to help, whether you buy any parts or not.

Thanks,

G

gbevans@peoplepc.com

 

My 98 F150 4x4 Offroad has the 4R100. It has 150K, I think the shifts are too soft, but it works for the most part. The tranny cooler helps with life. The pan came with a drain plug as did the torque converter.

 

I have the same set-up as ane182rf and since I use my truck to tow around my jeep I added a cooler (for 26000 GVW) and a filter/gauge kit from perma-cool. Now my tranny runs at about 150 and the cut-out in the bumper works as a nice funnel for air to the cooler and the cooler hides the filter so you cant see it through the bumper

 

I had wrongly assumed for so long that I had the 4R70W on my 99 F150 XLT ext Cab 4x4. I just seen this thread, https://www.f150online.com/forums/tr...nsmission.html and have the TR code E. I read this is rare.

In 2008 in Virginia it stopped shifting into 2nd gear Automatically. All the gears work fine, no strange noise, it just doesn't shift into 2nd automatically. My wife at the time took it to some place and the fellow said it was the 2nd gear shift solenoid, probably, and it would cost $750 to replace, but that may not fix it. I put off the repair because of other things more pressing, and a couple months later towed a two axle trailer to SW Louisiana. While I was in Louisiana I contacted another shop, a tranny shop and the fellow said on the phone that it could be the wire to the solenoid, but wouldn't know for sure until he got into it. Well my gig in Louisiana ended before I got around to having him look and I ended up pulling another two axle trailer to coastal Oregon in 2009.

So here we are today, 224,000 miles and I four years after first seeing this problem. I have decided to tackle it myself. I may have fixed it all those years back if that fellow didn't say that replacing the solenoid may not fix it. I have decided to read the manuals and websites really well before tackling this job. Wish me luck. I have never had a Tranny apart before (although I have had a few engines apart in my younger days). I read some fellow mention that some ***** fall out when you drop the pan. That is the kind of thing that kept me out of trannys my whole life. arrgghh

 

No check ***** will fall out when you drop the pan. It's if you drop the valve body.

First thing to do is check the wiring to each shift solenoid (there are two) from the PCM to the trans for continuity, shorts to ground, and shorts to power. Disconnect the wiring at the PCM and at the trans to do this. Don't stick a probe in the end of the wiring, probe the back of the connectors. If this checks good, the problem is probably a shift solenoid. You can remove the pan and check for resistance across the two pins of each solenoid. If a solenoid is bad it will have an open circuit. Check this with the wiring unplugged from the solenoid. If the solenoids test good, then the problem is the wiring harness inside the trans. It is readily apparent with the pan off.

 

Thanks, this is the reason I joined this site and read it all the time now. You sound like you know you stuff and I am an electrical engineer so I understand what you said. A good tranny man in Louisiana said it could be the wiring and a kid in Virginia told me that it was not guaranteed that a $750 solenoid swap would fix it. No special tools and just a little bit of my time. Now I just have to go find those wires you talk about. Fixing this will make me happy... Especially if I do it myself and save a stack of money.

 

Is the 4R100 and the 4R70 wired the same way externally? I found a deal on a 5.4 and 4R100 and want to know if I can slide out my 4.6 and 4R70 and slide in the 5.4 and 4R100

 

Nope, there are some mods you have to do - a 4R70 computer won't work with a 4R100, among others.

 

Definitely not as easy as sliding one out and the other in. You will have to swap computers and wiring harnesses and then re-program for PATS. That much at the very minimum to start. It's a real project.

D