4:10 Gear swap?

[Quik9r]

1974 GMC 3/4 454 TH400 2 WD with 4:10 gear (factory 8 bolt rims) what is the simplest way

You must be registered for see images attach

to have a highway gear without butchering this cream puff survivor?

 

[Memaloose]

Overdrive unit I would say.
Very nice looking pickup.
How about 10-12 more photos, green's my favorite color!

 

[Shorty81]

Welcome, wow that's a beautiful truck! JMO, I would leave it stock. Rare truck for sure.

 

[CalSgt]

Have taller rear end gears installed and save the R&P that came out of it for if you ever want to put it back.

Ring & pinion can be replaced without any major or permanent change to the truck.

 

[SquareRoot]

GV. Not the best solution but meets your criteria.

 

[Grit dog]

Have taller rear end gears installed and save the R&P that came out of it for if you ever want to put it back.

Ring & pinion can be replaced without any major or permanent change to the truck.

What he said.

 

[rt66paul]

Set it up for a period 5th wheel trailer and use it as intended.

 

[Grit dog]

What he said.

PS, THAT ‘74 is about one of the coolest looking squarebodys I’ve ever seen!
I can attest that it is likely not hardly drivable at highway speeds.
My 4.10s no OD sitting on 35s is at 3000rpms at 70 mph.
It’s nice to drive around town and the back roads. But she’s screamin if I hop on the freeway and don’t drive like an Asian!

 

[Craig Nedrow]

What Grit dog said applies to my K20 4:10 with 35's. I am just starting to swap my TH350 to a 4L80E. I will use a US shift stand alone controller. GO here: https://www.usshift.com/usq4.shtml. It would be like falling off a log easy, as you would just need to shorten your driveline a couple of inches. Go here for specs: https://gearstar.com/overview-4l80e-transmission/ This would cut your RPM'S 30%. I bought one out of a 2008 3500 box van, 45000 miles, 350.00. Have another one for my LQ4 that I am building for the 54 PU.

 

[dvdswan]

Welcome to the site.

 

[SquareRoot]

Set it up for a period 5th wheel trailer and use it as intended.

Huh?

 

[boltbrain]

What Grit dog said applies to my K20 4:10 with 35's. I am just starting to swap my TH350 to a 4L80E. I will use a US shift stand alone controller. GO here: https://www.usshift.com/usq4.shtml. It would be like falling off a log easy, as you would just need to shorten your driveline a couple of inches. Go here for specs: https://gearstar.com/overview-4l80e-transmission/ This would cut your RPM'S 30%. I bought one out of a 2008 3500 box van, 45000 miles, 350.00. Have another one for my LQ4 that I am building for the 54 PU.

If I put my 1979 in first and Low4 it goes about the speed I walk. They feed cows without anyone driving, just tie the steering wheel. I like my SM465 and the NP205 T-case and got to thinking if I swapped the diff gears to say, about 2.5, that would make my 4th in the SM465 like a 5th on a NV4500 as far as engine-to-wheel ratio. The NV4500 is often paired with 3.54 gears I think. Fifth is .69 or .72. 2.5 diff gears would move each gear up so as to lose granny gear, but the low on the T case is still available in two or four wheel drive. My question is has anybody ever done this and if so how did it work out? Thanks