4R70W Torque Converter ?

[fordguy]

should i just go with the stock explorer converter, i am running exp efi with 4.88s. my goal is to drive to OCBR and do mild trails and enjoy the show. i live several hundred miles away.

 

[rjrobin2002]

I love the way the stock Explorer torque converter felt in a Bronco I built with 5.13s and 38" tires and in another that had 4.11s and 35s.

 

[Broncobowsher]

The stock Explorer convertor is a very nice unit. Good creep force at idle and when loaded hard pretty good stall speed. Being a lockup convertor you don't need to worry about the higher stall speed. The lockup makes the convertor slippage go away.

I ran the stock Explorer convertor behind a decent built but grunty 351 for years. With 4.88 gears and only 33" tires I drove it from Phoenix to Vegas for 3 years in a row. It made for a really good highway driver that would also wheel great as well.

 

[SSDDBRONCO]

I love the way the stock Explorer torque converter felt in a Bronco I built with 5.13s and 38" tires and in another that had 4.11s and 35s.

How did the Bronco run with 4.11s and 35s?

 

[bronconut73]

I run 4.11's, 35's, 351W, and a C-4 and it is just about perfect, but if I went with a 4R70W I would need lower axle gearing to use the overdrive according to our friends here at CB.

 

[fordguy]

ok sounds like stock will do great, not sure on the 4.88s still considering 5.13s

 

[fordguy]

what is the overdrive ration on the 4r70?

 

[sanndmann3]

.7 is the 4th gear ratio.

FYI, the local auto parts store listed a couple choices for replacement torque convertors for a 4R. "low stall" and "high stall". no other specs listed... I had the opportunity to try them both as I burned up my 1st rebuilt trans. I'd recommend the low stall unit...

 

[fordguy]

.7 x gear ratio should give me final drive ratio?

 

[bronconut73]

3.51 would be the final drive ratio with a .72 overdrive and 4.88's
Brings you back to 3.5 to 1 stock axle gearing which is great for 31's, 32's, maybe even 33's.

 

[rjrobin2002]

How did the Bronco run with 4.11s and 35s?

Drives good in flat La, but the hills in other parts of the world would cause downshifts at 70+. It would be perfect with 4.56.

 

[Broncobowsher]

Aim for about 2000 RPM at 60 MPH and it will be happy. This is for a typical small block ford V8 in a typical early bronco. Minor adjustments should be taken into account for location (high elevation mountains will need lower gears, flat low elevation will accept less gearing). Engine choice (torque built 408 stroker can run less gear, small displacement with high RPM camshaft will need more gear). And other drag factors can also impose additional loads that will need more gearing. There are too many personalization choices that have too much influence to have a single gear ratio that will work for everyone.

The advise is to gear just the rear axle when you are ready to try something new. Go drive it. Don't be afraid to not like it. Once you get the rear into a happy ratio, now spend the money and effort to gear the front to match.

 

[DirtDonk]

31's (29.5" effective rolling diameter) and 4.56's with a stock Explorer converter here. Yowza!

Paul

 

[rjrobin2002]

31's (29.5" effective rolling diameter) and 4.56's with a stock Explorer converter here. Yowza!

Paul

Your prolly running 13 second quarter miles, that thing should fly.

 

[DirtDonk]

It would if it could get the traction! Those BFG muds don't do much more than sit there and squeal when you give it the juice.
VERY stock engine, but the low gearing changes how it acts drastically, down at the low end.

And even with all that gearing it's still just loafing along at 2400-ish rpm at 65 all locked up in overdrive.

Paul

 

[fordguy]

Aim for about 2000 RPM at 60 MPH and it will be happy. This is for a typical small block ford V8 in a typical early bronco. Minor adjustments should be taken into account for location (high elevation mountains will need lower gears, flat low elevation will accept less gearing). Engine choice (torque built 408 stroker can run less gear, small displacement with high RPM camshaft will need more gear). And other drag factors can also impose additional loads that will need more gearing. There are too many personalization choices that have too much influence to have a single gear ratio that will work for everyone.

The advise is to gear just the rear axle when you are ready to try something new. Go drive it. Don't be afraid to not like it. Once you get the rear into a happy ratio, now spend the money and effort to gear the front to match.

Good advice, except that horse has already left the barn. i built a 4.11 front end that has never been run. live and learn, well and spend some money

 

[bronco loco]

My Bronco has 4.10's and the 4r70w with stock explorer converter and hits 2100 rpms driving at 65mph.

 

[Broncobowsher]

My Bronco has 4.10's and the 4r70w with stock explorer converter and hits 2100 rpms driving at 65mph.

On what size tires?

Bet it drives pretty nice.

 

[bronco loco]

30 inch tires.