regearing 4th gen 4.7L

05christj · Jul 29, 2015

Hello all, I am looking for input from 4th gen 4.7L owners who may have regeared or has the stock 3.92's.

My truck has 3.55's on 33" tera grapplers and it is an absolute slug, it has to downshift at the slightest incline at 70mph.

My question is, will regearing to 3.92 help quite a bit? Or is it not worth it?

HammerHead · Jul 29, 2015

05christj said:
Hello all, I am looking for input from 4th gen 4.7L owners who may have regeared or has the stock 3.92's.

My truck has 3.55's on 33" tera grapplers and it is an absolute slug, it has to downshift at the slightest incline at 70mpg.

My question is, will regearing to 3.92 help quite a bit? Or is it now worth it?

4x4 or 2x4??? I went 355 to 410 and wish I would have gone 456. And my truck is a street truck. 355 to 392 is waisting you $$ in my opinion. 410's minimum.

Galion · Jul 29, 2015

HammerHead said:
355 to 392 is waisting you $$ in my opinion. 410's minimum.

I agree with this, if you're going to spend the time and money into regearing, it's hardly worth it to just go from 3.55 to 3.92. That little a change really would be hard to justify the costs.

gassersarentdead · Jul 29, 2015

A slug on 33s? I doubt it.

regularcab2500 · Jul 29, 2015

gassersarentdead said:
A slug on 33s? I doubt it.

I know it to be true, the 4.7 with 545rfe is a dog with even stock tires. As others have stated, 4.10s minimum or its not worth the money.

gassersarentdead · Jul 29, 2015

That's my bad. Was thinking a 5.7

05christj · Jul 29, 2015

It is 4X4

Moss · Jul 29, 2015

What about 33's with 3.21 and a 5.7L...

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HemiRoar · Jul 29, 2015

Moss said:
What about 33's with 3.21 and a 5.7L...

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Mine had 33s with 3.55 & 5 speed on stock 17" rims. It went.

3.21 & 8 speed can't be too different my setup.

Galion · Jul 30, 2015

Moss said:
What about 33's with 3.21 and a 5.7L...

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With the 8 speed I doubt it would be too bad actually. The 8 speed's first two gears are much lower than the 6 speed so even with 3.21 gears it shouldn't be bad.

DannyMK2 · Jul 30, 2015

go 4.56 and dont look back.

QwikKota · Jul 30, 2015

8 speed and 3.21's are not bad and first is fine but a lot of times when you come to a stop sign and do a very slow roll it will stay in 2nd gear, this is where the 3.92's make a big difference. That and overall accel and towing of course. If you come to a complete stop and let the suspension settle the tranny will go into 1st, sometimes with a light clunk, and take off is fine then. First gear at 4.7:1 is very short.

regularcab2500 · Jul 30, 2015

DONT YOU BOYS FORGET, THE MAN HAS A 4.7L AND 545RFE. The 8 speed tranny is totally irrelevant to this thread as well as the gearing with any hemi truck. His combination (which my 2010 had) is more comparable to the 3.6L pentastar and 65rfe combo than any hemi.

05christj · Jul 31, 2015

regularcab2500 said:
DONT YOU BOYS FORGET, THE MAN HAS A 4.7L AND 545RFE. The 8 speed tranny is totally irrelevant to this thread as well as the gearing with any hemi truck. His combination (which my 2010 had) is more comparable to the 3.6L pentastar and 65rfe combo than any hemi.

Thank you, I think I'm going to go with 4:10's, I fear that with 4:56's I'll drop to 10mpg freeway.

regularcab2500 · Jul 31, 2015

It depends how much freeway..i think 4.56 would liven up that motor a ton but if you mostly drive on the highway, you'll probably be spooling too much for comfort. I do mostly city so i cant wait to get 4.56s in my truck. You cant go wrong with 4.10s behind the 545rfe though.

05christj · Jul 31, 2015

I drive mostly freeway, my commute to work is about 30 miles one way.

regularcab2500 · Jul 31, 2015

Whew..if youre looking for compromise, i think you can get 4.30s for the 9.25 rear. But 4.10s should be enough. Those would still put you around 2000rpm at 70mph.

regearing 4th gen 4.7L

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