Chevy & GMC Vans

1. Has anyone ever done a detailed measurement/sketch of the engine compartment of the astro to be used to determine whether a 4bt or other diesel would fit? What would be ideal is if someone had a cad drawing of the engine compartment. Measurements would be OK though

2. Someone has mentioned that the auto tranny for the V8 engine will fit on the v6 engine and, with an adapter, will fit a diesel, even with the extra torque. My question - would the gear ration on the V8 tranny be appropriate for a diesel engine? My guess is, no.

It's not the tranny ratios that really come into play it's the rear diff. Since a diesel turns slower with greater torque it's not uncommon to find rear diffs in the low 3s.

I would do the install, take it for a drive and then regear the rear end as needed, as long as you can cruise at a good RPM on the highway you should be fine. my dually has 4.10's and only does about 75Mph... I could lower the ratio to get more top end, but it is not really needed in a big truck

pengyou wrote:1. Has anyone ever done a detailed measurement/sketch of the engine compartment of the astro to be used to determine whether a 4bt or other diesel would fit? What would be ideal is if someone had a cad drawing of the engine compartment. Measurements would be OK though

2. Someone has mentioned that the auto tranny for the V8 engine will fit on the v6 engine and, with an adapter, will fit a diesel, even with the extra torque. My question - would the gear ration on the V8 tranny be appropriate for a diesel engine? My guess is, no.

Or your could spend and get:

http://WWW.gearvendors.com

You can get a cummins 4BT out of a bread van they used a GM TH-400 transmision. No adapter needed, they bolt right up to GM transmissions.

The transmission has to be diesel specific as the diesel has low opperatring RPMs. That means the gas transmission would not shift correctly for the diesel engine. Its not a serious issue as Im sure a transmission shop would be able to set up the transmission correctly.

A 4BT should fit anywhere a 350 V8 would fit lenth and width wise. The hight is what you will need to know as the cummins are rather tall engines.

Yes, it is the height that I need to be concerned about. Weight is also going to be an issue as well. The 4bta is heavier even than the v8 350 - I think by more than 100 pounds, and then there is the added weight of a heavy duty radiator, second battery, etc.

The overdrive would be awesome but at about $ 2,800 I think I will either buy a new tranny or a new rear end and take the $ 1,500 I save and buy pop tarts

If you want to use your transmission you will need a lower stall torque converter, some sort of electronic shift controller would be a nice option aswell