The Stovebolt Site Forums The Shop Area Driveline 1949 chevy 6400 2 speed axle better gearing?

Hey whats up bolters,
so ive decided to do the t-5 tranny swap into my 1949 chevy 6400 and wanted to find some info on some gear sets for my rear 2 speed axle.anyone know anything about that? i want to keep that axle so it still looks like he same driveline from behind but has a little more gearing to get past 55 mph.
-Dan

Some would say that the transmission is a bit light for the truck.

Ive heard that the t-5's pulled from the 6cyl applications hold up pretty well to the 261 that im running now. What have you heard?

Are you going to haul anything with the truck. It is kind of out of out of the ordinary to put a T5 in front of a 2 speed, but it should work. It depends on which T5 you get. The world class T5 will handle a pretty beefy engine. An OD transmission is the only practical way to go faster. That is if you have enough HP to pull it, the steering to keep it on the road and the brakes to stop it.

I assume the T5 has close ratios.This would be a very big improvement over the older designs.

Your better bet would be to use an NV4500 as it has overdrive and is at least a reasonably strong transmission.

Even if your not hauling much in a 6400 series truck, a T5 seems like a bad choice unless you like burning through transmissions.

Not trying to discredit the idea, but be prepared that it may not hold up in the long run. It will not hold up if you pull weight.

Jeff

One more thing, you won't find a better range of gear ratio than the 6.11 in high that the 2 speed has. I think it has around 8.17 or some such in low range.

Jeff

Is the nv4500 a direct bolt up to my 1962 chevy 261? And would that tranny be a good mix with the gears i have now in the rear end?

Dan

What are you trying to do?
I ask because the slow gears in the rear axle might be the biggest problem (usually are) and throwing transmissions at it won't make enough difference. Swapping rear axle and possibly transmission too might be the answer... depending on your goals.

The right NV4500 and or with the right adapter can bolt up, it's a good and common swap. Good choice for a full size truck. The T5 is a good choice for a small truck.
bigbadswingdaddy knows his stuff and I'm sure has detailed answers for you.

One of many threads on the subject
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=620037

Grigg

So back to my original question, is there gear sets i can replace in with the current axle i have now? then doing that along with my nv4500 swap? good choice?

previously answered

[quote=Grigg]What are you trying to do?
I ask because the slow gears in the rear axle might be the biggest problem (usually are) and throwing transmissions at it won't make enough difference. Swapping rear axle and possibly transmission too might be the answer... depending on your goals.

im just trying to make this thing into a weekend driver.no heavy loads. so the nv4500 and my stock axle gearing would be a good mix?

A NV4500 is a good choice because it gives you a .73 overdrive. You will not be able to accomplish that with different rear gear sets. But be prepared to fork out about $1000 or more before you are all done.

Here's a gear calculator
http://www.onlineconversion.com/bigger_tires.htm
With it you can plug in your numbers and see what your different options will do as far as RPM and MPH.

looks like the 0.73 OD on the NV4500 will take you from 45 ish to about 60 mph at 2,500 rpm (with 36"? tires). That seems plenty unless you've got more power and good/better brakes too.

Plug the numbers in and see what you get and what you can live with.

Grigg

if thats true, thats about what im lookin for.ill play around with that calculator.thanks! now to go hunt around for an nv4500.

dan