The 4R75E is fully electronically shifted. Also a little stronger then 4R70W. Biggest difference is the electronically shifted. You can still do the Jmod on them, but because of the electronic shifts there is still a big delay before and after the shift. Its a form of torque management to help make the transmission last longer.

 

Calling a transmission a 3 speed with overdrive dates back to the old days where there were 3 speed manuals with a separate overdrive on the tailshaft - that could be engaged in 1st and 2nd with a mod and you did not have to disengage the clutch to engage and disengage it. Technically, any ratio lower than 1:1 is an overdrive and higher than 1:1 is an underdrive.

As I remember, the old overdrive would engage at any speed over 25 mph in 3rd gear by lifting your foot off the gas - and would disengage when you dropped under 25 mph, or floored it. I had a 80 Volvo with a 4 speed plus overdrive - there was a button in the shift **** to engage and disengage it on the fly.

 

In 1964, I bought a used 1959 Chevrolet Impala 2 dr hardtop with the 230hp 283 cu in engine. It had a 3 on a tree with electric overdrive. The stock rear with that combination was a 4.11!! The wheels were 14". Occasionally, I would wind it up in first gear enough to get overdrive. With that rear, the car was surprisingly quick. Loved that car. The front seat was large enough for some serious girl friend activity!

Only problem I had with it was that it was the second year Chevy had coil spring rear suspension and the rear only had 2 lower control arms and one upper attached to the right side frame. I kept almost ripping off the attaching point for the upper control arm. I had it welded back 4 times. I drove it from 29k miles to about 75k and traded it for a 4sp 300hp 65 chevelle!!

 

I have a 2001 f150 4X4 7700 and it has the 20 bolt pan underneath, the code seems to be a 4r100 tranny. It was last documented to be serviced at 60000 miles, I just bought it this last weekend and it has 127000. The dealer says 200 bucks to put it on a flush machine and they say no need to change the filter if it is on the flush machine. should I just drain it myself and change the filter? or should I have them put it on the flush machine? Thanks, EJ

 

Check to see if the torque converter has a drain plug like the 4R70W torque converter. If it does you can drain all of the fluid and I would do it myself. Besides, I'm sure you would like to see what if anything is in the pan.

I always install a drain plug in the side of the pan to help drain it the next time. Those plug kits tend to leak for me so I get some oil pan drain plug washers from Advance and use that to make sure it seals. The washer is metal with rubber in the inner ring.

The reason I put it in the side of the pan and not the bottom is to eliminate any chance of it dragging on something and getting ripped out. It isn't going to drain all of the fluid anyway, but it will get the level below the gasket and help keep you from taking a bath in transmission fluid. Also, look at the transmission and the pan to figure out where it can be installed without interfering with the valve body. Guess how I learned that!

 

So, your saying if you were me you'd do it yourself? I think it has a drain plug already. SO, I guess it has been installed previously. Thanks for the info. EJ

 

The 4R70W is also fully electronically shifted.

 

Just sold mine last month with 180,000 and original transmission. To top it off the truck had a 3.08 rear end which didn't help the tranny out too much. Either way, with regular maintenance it is still going strong and the new owner is really enjoying her (he is a mechanic btw ).

 

 

Food for thought! Would not recommend a trans flush, if there is "gunk" in the tranny what that does is cleans it out, which in theory isn't a bad thing. But from first hand experience it removes the gunk that may just be keeping things "bonded". Most garages around here recommend you just drop the fluid and change the filter.

Just thought I would put it out there, had that problem with my 2000 did a flush and within a week I could only get reverse the first stage clutch packs let loose...

 

The 4R75E actually has some harder parts and other improvements over the 4R70W. That article above seems to be from only an electricals perspective. There are other differences than just the addition of a turbine speed sensor.

Darrin