Chevy & GMC Vans

More day dreaming, anyone know of a PTO transmission that would work with our vans.

Strange you should bring that up just now. I've been investigating 'manualizing' the transmission in my '89 and one of the transmissions I've looked into is the NV4500, a 5 speed transmission. It has a mount for a PTO, but this transmission's first gear ratio is something like 6.3:1. Multiply that through your van's rear ratio and you've got a creeper gear for pulling tree stumps and shunting boxcars. I don't see a street application for this transmission in an Astro, but I bet Dean does!
Here's a breakdown of an NV4500 (just to get Deam salivating):
http://nv4500transmissions.com/parts/index.htm

Rob...you need a 4500?

My buddy Darrel has the one that was behind his Cummins diesel for sale. The engine came apart so he is selling off the parts. You are right though the 1st gear is real low! It would be perfect for a 4x4 rock climber. The first gear being so low is really only used for starting off with a heavy trailer. Normal use is starting in 2nd for a more normal street gear. It still has 5th gear OD so it would be an awesome tranny for a manual shift Astro or Safari.

Ya I've heard of crawler builders hunting for that tranny specifically because of that granny low first gear.. Atleast before doublers and such came along.

There is another tranny out there with a granny low first gear aswell..... I can't remember which one tho LOL.

I know you could find it in mid to late 90s 3500 Silverados. There was alot of fuss over this tranny because dummie buyers who didn't know there butt from a hole int he ground would buy a truck with it and then come back for warranty work over and over and over saying there is something wrong with first gear. So much so that when they came back with that "condition" multiple times GM started swapping them to a tranny with a more street able first gear.

Also what crazy idea do you have that requires a PTO?

LiftedAWDAstro wrote:... It still has 5th gear OD so it would be an awesome tranny for a manual shift Astro or Safari.

Now, why did I know that Dean would answer this way?

The original "granny low" transmission is the SM420, which was used from the early 60's until it was replaced by the SM465. The gearing is about the same between the two, both are basically a functional 3 speed, with a bonus granny gear in both. The plus side to these, is that they are available in 2wd and 4wd, and they are very short, so you could use them in a divorced setup for ease of placement of components.

potskie wrote:Also what crazy idea do you have that requires a PTO?

Just thinking about the cool stuff it could power, ie generator, air compressor, aquatic jet drive for amphibious conversion. I have more day dreams than time or money.

potskie wrote:There is another tranny out there with a granny low first gear aswell..... I can't remember which one tho LOL.

I know you could find it in mid to late 90s 3500 Silverados.

I am pretty sure that is the NV4500 as well.

I don't know if this is of any help, but the NP241HD transfer case that was an option in Dodge 2500's and standard in duallies has a pto output. It has a cover over it from the factory. My 98 2500 has one. Note: it has to be the 241 "HD" to have the PTO. I've contemplated (briefly) bed mounting a wrecker winch and powering it with the pto.

post resurrection time

So i couldn't help but think about this idea again and again lately and i don't see why it can't be done in a similar manner as our starters are set up with a bracket holding a gear to the flywheel with a electronic clutch on the output shaft.

I had a 1988 Chevy Silverado pickup that came stock with a 305V8 and a 5 speed (4 with OD) Getrag tranny. I don't remember what the gear ratios were but i do remember 1st gear being really low. So much so that I used 2nd gear as first a lot. But i did pull a trailer with that truck and never had a problem getting it moving.