454 to Cummins

[GCinSC2]

Look up specs for current model year numbers, the torque wars continue.

[SpiceStream]

Not sure if this is a conversion anyone is considering doing or in the middle of, but I would say it is definitely worth it. I bought a 1984 310 with a 6bt/Allison 545 conversion and Gear Vendors Overdrive and it rolls down the freeway like a dream. I bought it 2000 miles from home, towed a car home with it no problem, averaged 14MPG as well doing the speed limit all the way. Let me know if you need any info on the swap, I did not do the swap but I have the Motorhome and the guy that did the swap has become a good friend so I can help in one way or another.

[shepherd57]

How is the Gear Vendor connected to the Allison 545. I have the same setup but no overdrive.

[SpiceStream]

It is mounted midship, I will find out if the drive shaft was cut and re-worked or if there is a drive shaft combination that works. My guess is the former. I will say, it gets you gear you need for modern highway speeds. The cost to add it was not trivial, but I can say it is nice. The Tach is not functional in the coach, but when I get that working, I will post the RPM and speed Specs.

[SpiceStream]

I can get you a copy of the GV manual if it is not available online if that helps.

[shepherd57]

That would be great if you could do that. I have the Isuzu diesel with the 545 and it needs another gear on the highway to bring the revs down.

Is the gear vendors mounted midships where the hanger bearing was.

[SpiceStream]

just ahead of the hanger bearing.
i will try to get a better picture tomorrow morning.

[choctawmel]

Originally Posted by SpiceStream

Not sure if this is a conversion anyone is considering doing or in the middle of, but I would say it is definitely worth it. I bought a 1984 310 with a 6bt/Allison 545 conversion and Gear Vendors Overdrive and it rolls down the freeway like a dream. I bought it 2000 miles from home, towed a car home with it no problem, averaged 14MPG as well doing the speed limit all the way. Let me know if you need any info on the swap, I did not do the swap but I have the Motorhome and the guy that did the swap has become a good friend so I can help in one way or another.

My conversion is still in progress. I've just taken the winter off and got out of town.
Thanks for the offer of helpful information.

[SpiceStream]

I am happy to hear that you are just taking the winter off, it would be a shame to not finish your project, you will love the end result, let me know if you hit any more snags, it looks like you are close.

[shepherd57]

Do you know the model of the gear vendors any I have seen mount to the trans in place of the trans tail shaft. How long is the drive shaft ahead of the gear vendor.

[choctawmel]

Originally Posted by SpiceStream

I am happy to hear that you are just taking the winter off, it would be a shame to not finish your project, you will love the end result, let me know if you hit any more snags, it looks like you are close.

I could get it done a lot faster if I'd just stop running off to ride my tricycle.
But then that's why I left for the winter so I could ride my little trike.

[GCinSC2]

Mel,

I know where that is, ate at Cattlemans once and the nearby but I think gone rib stand gown the road.

And bought about 3 pair of boots at Little Joes.

[choctawmel]

Originally Posted by GCinSC2

Mel,

I know where that is, ate at Cattlemans once and the nearby but I think gone rib stand gown the road.

And bought about 3 pair of boots at Little Joes.

Cattleman's is the best steak house in OKC for sure! We don't go there very often as I don't eat much red meat..... But when I do

[choctawmel]

Well boys and girls I have arrived home again. Tucson was nice, but home is home,
Walked around looking at what to do last/next. Took a while to locate the parts and get started in a forward direction.
found my new (right one this time) banjo bolt for my fuel pressure gauge. Then I had to find the hardware......
Then I turn to the mounting of 4 more gauges. I made a medal holder, but that didn't pan out, so, today I start working on a new gauge holder making it out of 3/8" plywood to mount to the windshield post. I glued and nailed this crud thing together. Then I'll see if it will fit.....
On another note: The rear end gear. Now it's a 4.56/1. I did a conversion program and the best I can figure at 1900 I'll be doing about 45mph. Anyone know if there's a 2 speed rear end that will fit in this thing? Anyone know what rear end is in these things?
Boy do I have work piled up around here!

[Smartstream]

Most of them have a Dana 70HD which has 4" axle tubes and disc brakes. You can get different gear sets but if you go numerically below 4:11 you need a different carrier. Never heard of a 2 speed option. Gearvendors is another option, spendy but gives you more gear options going down the highway. If I remember correctly 65 mph is around 2400-2500 rpm in overdrive with a Gearvendors.

[choctawmel]

Don,
You have an overdrive transmission with the GV?

I have the 4L80e now which is 0.75 OD which gives a finely drive ratio of 3.42.
At 70 mph was running 2300 rpm in OD w/torque converter locked.
With a 4.10 would run 2100 rpm at 70 mph.
Cummins red line is 1900 rpm. Can change the IP spring and get 2300 rpm but not something I want to do..... Yet

Gearvendor is an option, but $4000 plus? GV would give the 4.56 a 2.49 in double OD; 1700 rpm at 70 mph. 4.10 and double OD is 2.24 1525 rpm at 70 mph.

Looking at the numbers, the GV may be my best (only) option. don't want to run down the road at max rpm doing 56 mph, or change to the 4.10 and max speed of 63 mph

Good news is, I found a down load for my lap top to communicate with the transmission controller. No thanks to TCI. Im very disappointed with there total lack of support.

[Smartstream]

Originally Posted by choctawmel

Don,
You have an overdrive transmission with the GV?

I have the 4L80e now which is 0.75 OD which gives a finely drive ratio of 3.42.
At 70 mph was running 2300 rpm in OD w/torque converter locked.
With a 4.10 would run 2100 rpm at 70 mph.
Cummins red line is 1900 rpm. Can change the IP spring and get 2300 rpm but not something I want to do..... Yet

Gearvendor is an option, but $4000 plus? GV would give the 4.56 a 2.49 in double OD; 1700 rpm at 70 mph. 4.10 and double OD is 2.24 1525 rpm at 70 mph.

Looking at the numbers, the GV may be my best (only) option. don't want to run down the road at max rpm doing 56 mph, or change to the 4.10 and max speed of 63 mph

Good news is, I found a down load for my lap top to communicate with the transmission controller. No thanks to TCI. Im very disappointed with there total lack of support.

I assume you are asking me, I'm Dan not Don. At any rate I have a Gearvendors behind a non overdrive TH450 and Isuzu.

I think there may be some confusion of the red line of your Cummins. The max torque is at 1600 rpm, hp rating is at 2500 rpm and max governed speed is 2700 rpm. This site is a good info source. http://cumminshub.com/12v.html

Your Cummins will be happy at 2300 doing 70 mph with the 4L80e. If you feel the need for more speed then the Gearvendors is in your future. You can change axle ratio but then you pay with less power from the stoplight.

My old Isuzu is no ball of fire but 65 mph in overdrive is very comfortable going down the highway

[choctawmel]

Sorry Dan.... What rear gears you have?

[choctawmel]

Been working on a gauge tower for the 4 gauges I'm adding w/the diesel. This is my fourth prototype. The second is on the dash. I bought a couple, but they are for the slope of a pickup. I still may try to make one out of metal

[choctawmel]

I just check and the Gear Vendor to fit my application is $3295+55 shipping. I'd need a longer e-brake cable and a shorter drive shaft.
Trying to decide if I what to put a 3000 rpm spring kit in it????????