4:10 or 4:11 Rear end With a VS2 Transmission??

[Paso One]

Ever since Buddy Dawg mention this combination ( thumbs up day thread) I have been thinking of why it would not be a good thing for mileage on a  bus mostly on the highway.  Charles Seton mentioned NYBS ordered 4:10 rear ends with I assume the 4 speed stick and the 2 speed VH9 

I was under the opinion that it would be too much "overdrive"  But I'm re thinking this.

With the price of fuel and the fact the slower the engine turns the less fuel it would burn, running in the sweet spot in a extra overdrive situation.

Now some known facts  I drove Brian Browns Fishbowl with the VS2 transmission and a 5:38 rear end easily cruising at 73 to 75 Mph (pedal on Governor )

I put a 4:10 rear end in my Fishbowl leaving for now the VH9 2 speed trans  I cruise at 63 mph flat out pedal mashed.

I was planning on putting in the  3 speed V730 ( which requires significant bulkhead modification) which would give me good start ability and reasonably good highway speed. ( others say 65 -70 mph.)

Now the question: would it be to much of a overdrive  if I was to put in the VS2 transmission with the 4:10 rear end?

Mathematically and real life actuals would put the top speed ridiculously and unsafely high but the flip side would be 1/2 throttle cruising at 65 MPH  maybe 1400 to 1600 RPM

What am I missing here???   I know starting from a dead stop would require lots of throttle.

Any  04 or 06 owners running the VS2 tranny??   What rear end??

I got both a good rebuilt VS2-8 tranny and a unknown quality V730

Thanks for reading this brain twister 

[buddydawg]

One thing to consider is which VS2 tranny you have.  I posted the chart below from the VH-VS manual.
The VS2-6 has a 2nd gear ratio of 0.80:1 which should work with the rear end you have. Should be able to hit 80 and cruise at 70 without issue.  The VS2-8 has 2 version the .72:1 and .60:1 which in my opinion would be to much for the given rear end.  Also the first gear is the same as the VS2-6 and one of the VS2-8s and the torque converter ratio is the same so getting rolling should be the same as you are experiencing now.

On the other hand the V730 is more modern and should be easier to find parts/service but hey I'm rollin with a VH9 now.

Maybe some others with more experience with the forementioned transmission will chime in.

[TomC]

The V730 has a .88 overdrive which will put you at 1750rpm at 60mph with the 4.1, or 2040 at 70mph, which is perfect for the 8V-71.  If you went with the big overdrive with the VH9, you would need a turbocharged engine to be able to pull it.

I have a V730 in my bus with 4.56 ratio with 11R-24.5 that puts me at 1750rpm at 55mph or a top speed of 75mph at 2400rpm (I'm not trying to get 300,000 miles out of the engine-only 100,000 miles is fine).  The advantages to the V730-it is still in use, parts are still being made for it.  It is basically a HT740 without first gear.  You can get first gear torque converter lockup by pulling the gear shift to first with your foot on the floor then gradually pull up on the gas pedal about an inch, then you'll feel the trans bump into torque converter lockup making for a cool transmission on a hard pull.  Many a VS or VH transmission has burned up on long grades from being in 1st gear with no way to lock up the torque converter, a LOT of heat is produced.  Even with the bulkhead mods, it is very worth the trouble to use the V730.  Good Luck, TomC

[tekebird]

having both a VS and a V730 tranny in the family, both in 4108's, according to my Dad who has the most time in the driver's seat of both coaches he feels the VS is the more drivable transmission however It more or less requires a Jake brake while the V730 does not seem to need one.

[roadrunnertex]

FYI,
In 1977 GMC offered the V730 and the 4-1/8 rear end ratio in the P8M4905A's.
I have a V730 in my P8M4905A it was converted from a standard shift to the V730.
With the V730 transmission it makes the Buffalo a wonderful coach to drive.
On a trip to Florida 7.1 MPG out on the road at speeds 60 to 65 MPH.
The V730 is a good transmission and there are a lot of them around for spare if need be.
Go with the V730 and you will be ahead of the VS2.
jlv

[Paso One]

Great info guys keep it coming.

I have more or less committed to go with the V730 as I bought a Stone Bennett  shifter.

Just second guessing and wondering or giving someone else options.

[buddydawg]

I would stick with the 730 since you have it already.  I'm still thinking about goung the VS2-6 route, most of my travels are away from those long uphill grades.   The opinions I have heard from the folks who have used the VS series have been high.

[HB of CJ]

Turbo 2-stroke Detroit around 1500 to 1600 rpm cruise, with a non turbo 2-stroke Detroit around 1700 to 1800 rpm and maybe 1900.  Pick your mill type and highway speed.  The older Detroits did not like to run low rpm at cruise loads.  Good luck.

[Paso One]

I would stick with the 730 since you have it already.  I'm still thinking about goung the VS2-6 route, most of my travels are away from those long uphill grades.   The opinions I have heard from the folks who have used the VS series have been high.

I'm not sure what the difference between the VS2-6 and the VS2-8 is but the VS2-8 that I have Brian Brown said the previous owner of his bus had it rebuilt.  Also I have driven the bus that had the VS2-8 so I know it works good.

The V730 I have is just a take out from a parts bus I bought  5307 not sure how "good " it is.

P

[Utahclaimjumper]

I have the VS2-8 with a 5:55 rear end that leaves me slightly overdriven, 2250 rpm gives me 85 on the flat, engine is "A" timed with N65 brown tags with propane for the hills, works great.>>>Dan

[Utahclaimjumper]

Forgot to mention, bus is 4106 sports car at 26000 Lbs.>>>Dan

[buddydawg]

Paso, the VS2-6  2nd gear is .80:1 the VS2-8 has two versions   .72:1 and .60:1 which would  match better with the 5:38, 5:55 rear ends