1993 Chevrolet C3500 Crew Cab Restoration/Cummins Build

[90halfton]

Go for it. You're shooting for badass, don't come up short for $ sake. A few years from now you won't remember the money spent, you'll be glad you did it exactly how you wanted.

 

[JScott23]

I've already got the adaptor plate. I talked to the guys at destroked this afternoon about it, (who i would buy my allison conversion parts from) went over my expectations for the build, and they basically said they didn't think swapping to an Allison was worth it.

There are a few unknowns when swapping it to an Allison.

Speedo? Hopefully a dakota digital product can resolve that.

Shift linkage? My 4L80E has the 92-94 rod style linkage, rather than the cable driven linkage from the 95+ trucks. The allison is cable driven, not sure how much of a hassle this would be... (chime in if you know)

U-joint compatibility? I already have to have the driveshaft shortened, so a custom driveshaft isn't necessarily anything that i'd steer away from.


The Allison is much more durable, obviously, and the 6 speed would be nice, but its likely overkill for what i'm using the truck for. I'd be shooting for the 06-07 Allison, while staring down more than double the cost up i budgeted for a transmission. Also a much heavier trans, being a full planetary transmission. 335lbs compared to the 185lb 4L80E.

 

[90halfton]

I used to drill wells and run a pulling unit, we had to wrench on our own stuff. And these things are head to toe transfer cases, clutches, transmissions, and linkages. In some situations a person has to ditch a component, take a plasma cutter to everything associated with it, and then start from scratch fabricating the new thing to work, one aspect at a time. Starting to sound like your Allison idea will be the same kinda thing.

 

[JScott23]

If i go the allison route it will have to have a column shifter. Whether its the factory shifter or a later model column shifter. I'm going for a factory look won't be able to coap with a floor shifter or something else haha

 

[rolla711]

I would say if you can get a donor vehicle with the newer shift linkage I would just swap that over to your truck if that is easy to do that is. The Allison sounds like it would be a better route since it's already built to handle diesels. Also no need to worry about rebuilt issues and such, you follow?

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[JScott23]

I would say if you can get a donor vehicle with the newer shift linkage I would just swap that over to your truck if that is easy to do that is. The Allison sounds like it would be a better route since it's already built to handle diesels. Also no need to worry about rebuilt issues and such, you follow?

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I follow, but a donor truck doesn't really help me. It doesn't make much sense to spend a few grand for a duramax donor truck (even a roller) solely to take the steering column and transmission. Plus the column shifter linkage on the 06+ trucks is by no means compatible with the 93 column. I have seen the shifter handle with the manual control has been installed on the 88-94 shifter, but the shifter mechanism and linkage itself would not transfer to my column. Also worth noting the 88-94 trucks use a rod style linkage, whereas the 95+ trucks and all Duramax trucks all use cable linkage.

So that's going to have to be scratch made unless some LS guys have a simple conversion kit they've used in the past. Lokar makes one, not sure how easy it is to work with in a universal application. There is a little metal bracket for the rod linkage on the engine bay side of the firewall on the column that would have to tie into linkage of some kind, but idk.

Also 6 Allison speed uses a shift pattern PRNDM, whereas the factory 93 uses PRND321. So theoretically to do this swap halfway factory looking, I'd need to take the cluster out, and repaint the PRND321 with the Allison shift indicators of PRNDM, and wouldn't have a digital indicator for what gear I was in unless I got really creative.

The Allison is much bigger, and won't fit in the stock trans tunnel, but with my 2" body lift it should fit no problem.

 

[rolla711]

I was more leaning to the donor of a 96-99 obs, so that way cost stayed down but parts were newer and more adaptable to make the swap easy.

I figured you have the transmission already, or getting soon, so no need for a donor diesel of the same year of the transmission. I would have to agree that an ls swap has to go through the same issue you're speaking of if they used the newer style transmission

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[JScott23]

I was more leaning to the donor of a 96-99 obs, so that way cost stayed down but parts were newer and more adaptable to make the swap easy.

I figured you have the transmission already, or getting soon, so no need for a donor diesel of the same year of the transmission. I would have to agree that an ls swap has to go through the same issue you're speaking of if they used the newer style transmission

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Oh yeah. I'm not sure if you can run a 95+ column in an 88-94. I dont see why not but i've never tried it.

I guess long story short the deciding factor is $2000 transmission or $4000 transmission lol

 

[rolla711]

Real deciding factor is will you have to put more money into said 4k transmission or is it just a drop in kind of thing?

If it were me I would go with the transmission that is built for diesel versus the " universal" transmission. I say universal because how many things do people put it behind lol

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[90halfton]

Nv4500 and call it a day. The programming is super simple too.