351/4R70w into '93 Range rover

[CDW6212R]

Sonnax makes two different forward drums. I don't know why they look different colors, but the descriptions are virtually the same, and one comes with two other small parts(thinner retainer ring and thinner steel, to enable another extra friction to fit). This is the link to that one(76655-01K); http://www.sonnax.com/parts/4373-smart-tech-high-capacity-forward-clutch-drum-kit

The 76654-01k is made to hold six friction/steel sets, stock is five and people have forced six into the stock drum(leaving out the waved plate). The 76655-01K is said to allow seven to fit, but it will require the two thinner parts included, but note, also the uncommon OEM 0.036" waved plate. Using the typical 0.072" waved plate, six will fit easily.


It sounds like a rare failure of the OD band, which are not the strongest parts. I've had one band break like that in my old C4 trans. The connection at each end to the mounting lug are the weakest points.

The bands don't need the fancy Kevlar material, the high carbon normal bands of OEM or Borg Warner are great parts. The same goes for the rest of the frictions, buy a kit with normal OEM frictions, or similar color/materials. They are very good.

Don't skimp on the little things, like the torrington bearings and seals etc. The valve body is the brains and needs new solenoids and all Sonnax upgrades in general. I found a new one recently which is supposed to be an improved version of the pressure regulator, from Summit on eBay; http://www.ebay.com/itm/191879608096?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

If you don't have the Sonnax Sure Cure Kit already, do get that(and I think it has the older pressure regulator not the new kind(I'd call to see if they are updating that big kit)).

Inspect all of the hard parts carefully, the bushings inside the case and pump, planetary etc. Be sure there is nothing else off or a little rough. Hopefully from the time the band broke, nothing else got hurt.

 

[FIXR7]

Thanks Don,
The trans shop is getting all OEM parts for it so that's good.

 

[CDW6212R]

Very good. If you know what parts it had in it the first time, you might browse the Sonnax parts available, and Summit carry's some of them I think. the forward drum I mentioned because you have a 4WD application with what may be higher stress than normal, and that part didn't exist a couple of years back.

So you should be fine without it, but it's nice option. I'm going to buy that one for my supercharged project for sure, but maybe not for my others.

 

[FIXR7]

Cheers Don!
Trans shop have fixed it. Used factory band and replaced some frictions and put seal kit in it. Also removed the solid 1-2 accumulator spring so your brains don't fall out with the 1-2 shift anymore and I'm now able to adjust shift firmness electronically.
Been running good since re-installing on weekend.

 

[CDW6212R]

Excellent, well done with that.

 

[FIXR7]

Here's the busted band.. Note the yellow coating on back of band. The trans guy here says anytime he's seen one like that it's cheap rubbish...

 

[CDW6212R]

That's what happened with my first car, a 72 Gran Torino with a C4 trans. It lost the 2nd gear band just like that, and I drove it for about a month that way. Run it up to about 40mph in 1st gear, and let off it, it would go into 3rd in a second or so. That was the first transmission I ever rebuilt, made a big mess with two C4's on the driveway.

 

[FIXR7]

Ok I've noticed it still doesn't engine brake in 1 or 2.

 

[CDW6212R]

That sounds odd. Is there something different about that 4R70W, any odd non-stock parts in it?

 

[FIXR7]

That sounds odd. Is there something different about that 4R70W, any odd non-stock parts in it?

Looks like Hughes have used a transgo shift kit in it. But it used to work before the od band broke.

 

[CDW6212R]

I would contact Transgo or Hughes, or another expert about the trans braking. I don't know enough about it, but that is very odd if it doesn't hold while braking.

 

[shucker1]

Subscribed.

 

[FIXR7]

Well I'll be pulling the VB apart myself. Nothing's any good unless you do it your trucken self!!!!!!

 

[CDW6212R]

That will let you check it all out and see if anything seems odd or out of place, missing etc. If you think all it has for aftermarket items is the shift kit, I suggest buying the Sonnax o-ring kit which replaces a few end plugs to stop small leaks, and the new Sonnax Hydraulic Line Pressure Booster kit 4R70W-LB1.

I just bought that kit through eBay, from Summit, for $65. That should be a good improvement for any 4R70W, stock or modified. I'm putting that and the o-ring kit, plus new accumulators, into my 159k mile truck, for maintenance. I just bought the truck and it needs some care.

I doubt your build included the Sonnax parts, and the one kit is very new.

 

[FIXR7]

Thanks Don,
I'll look into that. I think Hughes use a transgo shift kit and I also doubt they use all the good sonnax bits. I don't think it needs line pressure to be boosted as it is though.

 

[CDW6212R]

That one I linked to is a progressive booster, no real change at lower throttle, but higher when you approach WOT. That helps holding power at higher throttle, and doesn't make normal shifting harder. I'll let you know how it does, I plan to put mine in tomorrow. My truck has 159k miles and the shifts are okay/stock, bland etc. All I'm installing are the EPC and a couple of shift solenoids, and the accumulators. I need it to be reliable for a while more before I build a trans for it and swap the BW4406 into it.

 

[FIXR7]

That one I linked to is a progressive booster, no real change at lower throttle, but higher when you approach WOT. That helps holding power at higher throttle, and doesn't make normal shifting harder. I'll let you know how it does, I plan to put mine in tomorrow. My truck has 159k miles and the shifts are okay/stock, bland etc. All I'm installing are the EPC and a couple of shift solenoids, and the accumulators. I need it to be reliable for a while more before I build a trans for it and swap the BW4406 into it.

Yes thanks Don. I read about that.
Anyway I've sent an email to Sonnax asking for all of the parts they make for the VB. I'll see what they recommend.

 

[FIXR7]

They recommended i buy a reman VB from them because of the tools required to fix the VB. I said I'd like to buy the tools also so I can do it myself. Besides I'll be building my own for my 6.8 V10 into Falcon ute project in the future

 

[CDW6212R]

Hmm, Sonnax provides valve bodies? That's interesting, and another trusted option. I don't think the 4R VB's are a problem unless they are older higher mileage units. Other than some mileage wear issues possible with certain valves and bores, the rest is easily user serviced.

If you think your VB might be worn from excessive mileage, a different VB might not be a bad idea. But I'd like anything with under say 125k, for serious power maybe you'd want under 50-75k, and could take a chance for a lesser vehicle with a 200k VB.

There are a few high wear issues with the VB that Sonnax does make tools to remedy, and the upgraded parts for them. But the need for those is very rare I believe, and some of them are very expensive. I just discovered that they have a new manual valve available, but it's intended to only replace a re-bored VB. Thus it's a larger part, feasible at maybe $40, but the special tool is $400. I liked the part until I read of the tool. Then I learned that the likelihood of a "loose" manual valve was basically pre-2001 models, and rarely needed.

It sounds like Sonnax has done a great job at discovering every potential internal leak, and designing a new part to reduce the leakage. But most of them seem to require a special boring tool, which they also put together, and each is not cheap.

So you want to work with a VB that doesn't have major issues, like most properly functioning transmissions. I've got three 4R's to work with for my projects, varying mileage from 29k to 95k. I like them all for using the cases and VB's, other than two being truck VB's. I'll use the 29k truck VB in my 99 Explorer with a decent 306, and the other truck VB has 75k and would be good for my 98 Mercury to rebuild that trans at some point.

If you think you need a different VB, shop around and try to get one from a car, 2001 or newer, preferably one 4R running fine without having been rebuilt. You can do any of the main stuff to it yourself, all but the serious high dollar Sonnax upgrades, which only a worn VB needs.

Did Sonnax give you any prices, and shipping for you?

 

[FIXR7]

Sonnax only gave me dealers to contact here and in the U.S. no prices.
I've suggested to Hughes they send me a new VB to replace mine. Will see what they say.