351/4R70w into '93 Range rover

[CDW6212R]

No, those are the higher pressure PR valves I said to avoid. The 2nd one is just an oversized version, notice the part number ending O/S?

The one I meant is this;

4R70W-LB1 - Ford AODE 4R70W 4R75E 4R75W Transmission Line Pressure Booster Kit

Ford AODE 4R70W 4R75E 4R75W Transmission Line Pressure Booster Kit 4R70W-LB1 Part No. 4R70W-LB1 Unique Forward & Reverse Boost Assembly Pressure Regulator Spring Line rise control in the AODE/4R70W is different than in most units. Forward pressure is controlled by EPC oil reacting directly...

transpartswarehouse.com

It's to raise the pressure by way of the boost valve circuit. That is a better way to do it, but it's not compatible with their older higher pressure PR kits, which come in the ZIP kit. They sell a simple quality replacement PR valve, that's the one to get to use with the above LB1 boost kit. Be sure you choose the parts for your model 4R, pre-98 or 98 up models.

 

[FIXR7]

Ok, Yes that's a lot of money for such a small part. Actually with mine I'm not unhappy about the way it works with the Transgo kit. I just need t o find out where the engine braking went.

 

[CDW6212R]

Okay, I forgot but do you think it happened after the transmission was installed, or during the time it was out? The torque converters slip inherently, and a different one might have more or less(stall speed difference).

If it happened later in the current combo, then it's tougher to figure out. Do you feel the trans shift into 2nd from say 30mph(50kph), and 1st at say 20mph(30kph)? It should be felt and then you have the higher rpm and some braking.

 

[FIXR7]

No Don, it stopped working even before the first time when Hughes sent me different accumulator springs to fit.
Even manually shifting, it shifts to and stays in those gears but when I back off...nothing.
I've got hold of Jerry and he's going to check his files but he's told me how for 1st you need the Low/Reverse band to come on and 2nd the OD band must come on.

 

[CDW6212R]

I hope he can help, or I'd contact someone else who regularly builds the 4R's. That does sound like a control(VB) issue.

 

[FIXR7]

I hope he can help, or I'd contact someone else who regularly builds the 4R's. That does sound like a control(VB) issue.

I think, If Jerry can't help no-one can.
So when you drive yours in Drive, when you come to a stop do you feel the downshift and consequent engine braking? I used to feel that when It was new.

 

[CDW6212R]

I barely can feel the downshifts when the shifter is in Drive. There's no engine braking at all in Drive. If I manually choose 2nd or 1st the rpm's jump up and there is solid engine braking.

 

[FIXR7]

Thanks Don. No engine braking at all in Drive? How do you feel the downshifts then?

 

[CDW6212R]

To feel them you have to pay close attention in stock form. They are there but it's made to smoothly shift into a lower gear when the rpm's get fairly low. The stock VB's are always calibrated to have smooth shifts, a built in slippage to achieve the smooth shifting. So anything which firms up the shifts should help to shorten the shifts, and make them more noticeable.

I haven't yet had the benefit of feeling the results of the VB upgrades I have suggested to others, in the 4R70W. I've got experience with many AOD's and one AODE Mustang, after shift kits were installed. That was20+ years ago though, before many of the Sonnax little VB kit/parts were developed. TransGo was always at the front of VB kits, both system correction kits(SysKo), and full shift kits. They always altered many things inside the VB, including lots of springs, and many larger drilled holes etc. The 4R is a well developed trans, based on what Ford learned with the AOD, and AODE. So the 4R doesn't need as much help, but the little things that are available should still be good to have. The J'Mod by Jerry is the best method to firm up the shifts, besides what electronic PCM tuning can do(that's about raising overall pressure and shift timing, but nothing else).

If you think your trans isn't working as designed, it may be time to go through the VB again, or change the VB. But they are good parts, very reliable unless they get worn out with bad fluid etc.

 

[FIXR7]

Thanks Don,
I'm beginning to wonder if the problem may be that when manually shifting I'm not using the actual shifter but the manutronic control of the Quick4.
Maybe engine braking won't occur in 1&2 without the manual valve being in the required positions? Is your shifter a 1,2,D with a separate OD button?

 

[CDW6212R]

Yes, the stock shifter has those three etc. The computer commands each gear with two wires, so four possible signals(--,-+,+-,++). That is a good thought, because for sure that's how that controller is doing it. What is your shifter, the pattern, does it have 1st or 2nd separately?

 

[FIXR7]

Im using a ZF 6spd shifter from a late model Falcon. It only has PRND and separate gate for “tiptronic” control which is purely electronic so it doesnt move the manual control valve any further than D. Can you be absolutely sure yours does not engine brake in D? If it doesnt i think we’ve found the problem?

 

[FIXR7]

I suppose I should ask the question?....Is the Explorer even a proper 4WD with a high and low range transfer?

 

[CDW6212R]

The stock transmission shifting is naturally set to hunt for the highest gear possible, to lower the rpm, for mileage. So it is surely holding each gear that it's in, but off the gas slowing down, it's staying in each gear as long as possible until the rpm's drop to a low enough point, it has to downshift etc. SO you don't actually notice down shifts off the gas.

The stock Explorer V6 4WD's have 4WD high and low, selected electrically with an electromagnet like an AC clutch. The V8's with 302 were either 2WD, or an AWD case which is one speed and a viscous clutch. If you hunt around this forum, you see lots of people who have converted their 302 with a true 4WD transfer case. The BW 4406 is the popular choice, it's strong and has a nice low gear, plus is available with simple manual shift levers, or the same TOD system as the V6 BW4405 transfer cases.

The BW4406 is made for the V8's with a matching six bolt pattern that goes onto most Ford V8 transmissions that came with 4WD. Lots of Ford pickups had it, well into the 2000's, plus the bigger SUV's with 4.6 or 5.4's.

I wonder if you can alter that shifter(the gate section) or another shifter to create the extra cable movement, for manual 1st or 2nd. If it is different for electrical control versus the manual valve in the VB, then that may be what you have to have to force it to lock into those gears.

 

[FIXR7]

Thanks Don,
Yes I think I'll do the test by just starting the car and with hand brake on disconnect the linkage and manually shift the lever on the side of the trans into 2 and 1. That should prove it. Then I'll just change shifters if that's the problem.
The Shifter I have is from a 6spd ZFHp-26(predecessor to the 6R80) equipped '10 Model Falcon. There is no way to modify it for any further mechanical shift range unfortunately.
Just a thought....Does the 5.0L(or 4.6) F150 4x4 of similar years have the same type of operation in terms of engine braking?
And, a final thought. I wonder if some worm hole(or other) mods could achieve engine braking in Drive?
Hopefully Jerry will pipe up shortly with his info about the oil flow circuit for the different modes of operation.

 

[CDW6212R]

I believe the 4R70 and 4R75 are virtually the same in functions. The 4R75 has an extra output speed sensor and minor differences in the intermediate parts, not much else changed. Any 4R that has just two bolts for the starter should be compatible with yours, which is the 302 bell housing pattern. Hopefully Jerry will have another idea to help.

 

[FIXR7]

Yes I'm aware of the differences mechanically and electrically. I just meant how they shift. Ie; maybe the F150 4x4 being a proper 4WD with high and low range maybe it already engine brakes in 1st and 2nd when in drive?
Maybe I'll bung a post on the F150 forum?

 

[CDW6212R]

There isn't any difference in the 4WD or truck transmissions, other than minor VB calibration changes. I think working on getting the manual valve to engage 2nd gear or 1st will be the answer.

 

[FIXR7]

Yes, I wanted to be sure before I put the VB back together and back in the vehicle. I want to know before hand so i don't potentially have to do things twice.

 

[FIXR7]

Ok Don, I just got a reply from a Ford trans engineer on the Ford truck forum. He says that it's correct that it doesn't engine brake in 1 and 2 when in the D position so, good news in one way. Bad in another.