Dmax into 93 Crew

[More Power]

The 1993 C/Ks were equipped with RWAL (Rear Wheel Anti-Lock). It's not computer controlled. It uses input from the vehicle speed sensor to determine whether to apply full brake hydraulic pressure to the rear brakes.

Jim

[Arlie]

Thanks Jim,
I'm going to have a look at both systems in alldata. I think I should be able to maintain the 93 RWAL.
It made me a little queasy cutting off that big bundle of wires coming out of the ABS unit.
I guess I'll just take it one little wire at a time.
Arlie

[Arlie]

Not much time for this lately (fried motherboard among other things ) but here's where I'm at.

Alldata shows RWAL and 4WAL for 93. Mine must be RWAL as I see no sensor wires at the front wheels.

For 1993, the ABS module (EBCM) gets a speed signal from the Vehicle Speed Sensor Buffer (VSSB) which converts the AC sine-wave signal from the Vehicle Speed Sensor(VSS) on the transfer case, to a DC square wave signal (also used by the speedo).

For 2005 there is no separate VSSB. The VSS signal (likely the same AC signal but I'm not sure) is converted by the Engine Control Module (ECM) to a "4000 pulses per mile" signal. This signal goes to a bunch of other places including the radio! (gotta boost the bass at 60 I guess).

So... I have to decide what language the 05 speaks that the 93 can understand (if any). I kinda doubt the 93 VSSB puts out 4000 ppm (not sure why). But maybe the 93 & 05 VSS put out the same AC signal. Perhaps I can run the 05 VSS signal through the 93 VSSB so it can whisper sweet talk to the 93 EBCM?

Then again, maybe the 93 EBCM can understand the 4000 ppm put out by the 05 ECM.

I'm beyond my scanty electronics knowledge base trying to decide which way to go. One thing I don't want to do is make the ECM mad (I just did that to my motherboard ). I wonder if tapping off the 05 VSS to feed the 93 VSSB would alter the signal and confuse or damage the 05 ECM.

I think the brakes function OK with the ABS disabled so that's another option but ABS is nice, even if it's only RWAL.

Any electronics gurus out there? Jim? (no rush)

Arlie

[More Power]

You could leave the 1993 VSSB wired & active - T'ed off the VSS signal leads, so your RWAL will continue to function as intended from the factory. The 2005 ECM will be expecting to see a 2005 EBCM, but you may be able to either defeat the code (using EFI Live) that looks for it or disable the light on the dash. Even if you do nothing, it won't affect how the engine or transmission performs.

The 4000 pulses per mile are generated by the VSS (Vehicle Speed Sensor) for a standard vehicle setup. The VSSB modifies that to reflect changes in gearing (tire size or diff gears).

I didn't reconfigure the RWAL on Lil Red. The module is still there, but was disconnected. A functional RWAL system only comes into play when the VSS is indicating zero speed. RWAL doesn't affect braking otherwise. This is why the brake pedal on an RWAL equipped truck can be pushed all the way to the floor (slowly and with some effort) when the truck is sitting still. The RWAL module commands the master cylinder to vent hydraulic pressure at zero VSS speed, which theoretically prevents the rear wheels from locking up on a low traction surface. As an aside, I know of a guy who had a power steering pump, a hydraulic brake booster and a master cylinder installed under warranty in his 1993 Chevy because he could push the brake pedal to the floor while sitting in the parking lot. The dealer mechanics didn't understand how the system was supposed to work either...

The braking system on Lil Red functions nearly perfectly without RWAL on most road surfaces. A panic stop from 60-70 on pavement applies braking power to all four corners in just the right amount. Might be more of a problem on icy roads, but.... it wouldn't be a big deal to make it functional.

Jim

[Arlie]

Thanks Jim (again).

I think northern Idaho is the icy road capital of the world. All winter we hover around the freezing point, melting a little during the day so we get a nice skating rink overnight. I've lived all across north-western Canada and never saw anything like this. Every other place I've lived a good set of all-season tires was just fine but here I change over to studs. Most people around here do. It's a bit of an adjustment for the Californians moving in. The body shops do well in winter.

Most vehicles I've owned haven't had ABS. I won't be bummed if I can't make it work, but I'm going to try your suggestion for making it work.

My biggest obstacle right now is finding rear door panels to complete my interior upgrade. I've got everything for the front in tan but have come up empty on the rear. The newer ones can be found but I'm striking out for 95-98. I might have to revert to the old vinyl ones. This part is a pain because I don't want to buy seats until I know what color scheme I'll have.

Arlie

[More Power]

I've considered converting a really nice 90's K2500 Suburban to Duramax/Allison power. If I did, I'd try to add the matching 4-wheel ABS system from the donor truck.

Here in Montana, any vehicle 11 years or older can be registered with the state DMV permanently - meaning pay for the vehicle license plates and registration once at about 2x the standard rate, and it's good for as long as you own the vehicle. I licensed Lil Red this way a couple of years ago. This reduces the cost of ownership considerably for those who own the same vehicle for a number of years. Cost to register a newer Suburban would approach $500/year. Cost to permanently register an 11 year old Suburban would be a couple hundred bucks.

Can't help you with the rear door panels.... except you might try Spaulding Auto in Spokane. As you know, they are a huge auto salvage & recycling center. They're just down the road from you....

Jim

PS. If the Duramax you're installing still has bright & shiny aluminum components, I recommend you buy some clear engine paint to coat all of the aluminum components while the engine is out of the vehicle, including the alternator and A/C compressor. All that spanky aluminum turns dark and crusty in a surprisingly short period of time when exposed to moisture & road de-icer. It's much harder to coat the engine once it's installed. I saw a Duramax conversion in an older Chevy while at SEMA last year. The owner didn't want to show it to me because of the nasty looking aluminum (he said no at first). He relented only after learning about Lil Red. You'll want to show it off after completing the conversion, as well as in the future...

[Arlie]

Thanks for the aluminum coating tip. I'll be doing that one.

I've been to Spalding and searched through everything there, looked all over EBAY, put up wanted listings in EBAY and Craigslist, but no rear panels!. The bad part is I need not only the panels but the inner support panels which makes it even harder.

It's a little confusing with body changes in 99. I think that the crew cabs and 3/4 and 1 ton models have the same body/interior from 95-00 whereas 1/2 tons and suburbans change in 99.

I'll keep looking for a while but it seems I'll have to cut my losses and revert to the old ones.

Arlie

[HCB]

The 2500/3500 frames and front suspension are a little wider in the engine bay (the wheel track is a little wider as well), when compared to the 1500 series trucks.

Any idea if this is also true between the 1500HD and 2500HD ?

Great thread, BTW.

[oilburnertoo]

Just thinking out loud here, I wonder if rear door panels out of a suburban are the same as the rear doors on a crew cab?? Might help expand your search?

[Arlie]

I believe they are the same and have searched with that option. I'm certain they're out there but it's the kind of item that doesn't get posted on internet listings much, and for whatever reason I'm not getting responses to the parts request submissions I've done.

I'm still thinking of going back to the original plastic. I have an aftermarket door lock system that works well. I could put the power windows I now have in the front and mount switches somehow.

I had a line on a brand new set of Dodge mega-cab front and rear seats (nice with power driver) that I could have picked up for under $700 with shipping but I let it go because they were gray and I have these beige panels and dash. Now I wish I'd have got them and just painted my plastic panels and dash to match.

I've not had time to work on it lately so no progress to report except that I did pick up a cool set of 22" rims that should dress it up.

Arlie

(HCB, I don't know the answer.)

[DmaxMaverick]

Any idea if this is also true between the 1500HD and 2500HD ?

Great thread, BTW.

Welcome to the Forums!

The 1500HD is the same as the 2500LD (8600 GVWR), and has a frame different from the 1500. The 1500HD was discontinued due to weight rating controversy. The 2500LD crew cab short bed is a carbon copy of the 1500HD. It was a marketing strategy that worked, but was pulled because of the weight fee and road tax base. When they first came out, I wondered how they were getting away with it. Apparently, the revenuers did too.

The 2500HD and 3500 share frame and hardware, except front hubs, wheels and springs.

[HCB]

Welcome to the Forums!

Thanks !

I've just been doing a little research, and what I found was that the 1500HD, 2500HD, and the 3500 all have the wider front track, while the 1500 and 2500 have the narrower front track:

* 2006 SILVERADO 1500 HD Short Bed Crew Cab
front track (inches): 68.6, rear track (inches): 66
http://tinyurl.com/2mvnmk

* 2006 SILVERADO 2500 HD Std Bed Crew Cab
front track (inches): 68.6, rear track (inches): 66
http://tinyurl.com/2ka6yh

* 2006 SILVERADO 3500 Long Bed Crew Cab
front track (inches): 68.6, rear track (inches): 74.7
http://tinyurl.com/3dk7nm

* 2006 SILVERADO 1500 Short Bed Crew Cab
front track (inches): 65, rear track (inches): 66
http://tinyurl.com/2wh6r4

* (No non-HD 2500s in 2006, but in earlier years):
2004 SILVERADO 2500 Short Bed Extend Cab
front track (inches): 65, rear track (inches): 66
http://tinyurl.com/32zgnq

Is it safe to assume any with the wider front track have the wider front frame as well ?

[DmaxMaverick]

Much depends on the year model we are comparing. 2006 and 2007-Classic shows different chassis specs than previous years, and the *500 designation is not the same chassis class as previous years on some models.

1500HD.....
2001-2003. Discontinued for 2004. Same chassis as the same year 2500LD.
2006. Reintroduced, but appears to have the same chassis as the 1500, which was touted to be upgraded. 2001-2003 had the same drivetrain and weight capacities available in the 2500, with an 8 lug full floater rear. The 2006 has a 6 lug, semi floater, much as the earlier 2500LD (GMT-400, 7200 GVWR), with an 8600 GVWR (same as the GMT-400 2500HD). Track specs vary by source, so I'll consider them unreliable. Without actually getting under them and measuring, I'd suspect any track differences are as much likely due to suspension/hub configurations. They do not have the same frame as the 2500HD/3500. I seriously doubt GM has a unique frame for a niche market.

2500 (GMT-800).....
1999-2004. Discontinued for 2005 and no sign of a return. Seems to be replaced by the now 1500HD. Doesn't leave a lot of choice for someone needing a 3/4 ton work truck. The 2500HD carries additional weight fees (in some states), and they don't always need a crew cab. Regular cabs are only available in 1500 (non HD) and 2500HD. There seems to be a hole in the lineup.

If that's not confusing enough, there were several mid model year changes that play into the picture. I did a side by side comparison of the 1500HD, 2500 and 2500HD in about 2002, of the chassis and drivetrains. Lost my notes, so I'm reciting from memory (about as reliable as my notes). I didn't measure, but one would not expect GM (or any other mfg) to have different frame widths for the same chassis. I could be wrong, but it wouldn't make sense, to me anyway. Not that GM would do anything that didn't make sense.....We'll see....

[HCB]

Oh boy.

I thought I had become LESS confused. One step forward and two steps back.

OK, I'm interested in dropping a later year Duramax/Allison into a ~2003 truck, but I want to know what to look for. I see with the new models that apparently you can only order the diesel package with the HD or the 3500.

Then I read 'More Power' posting that:

"The 2500/3500 frames and front suspension are a little wider in the engine bay (the wheel track is a little wider as well)"

so, I extrapolated ( :] ) that one needed to have the wider front frame to accept the diesel package. Hence, my question about which models have the wider front frames and noticing which are listed with the wider front tracks.

* Is this the case ?

* What do I need to look for or stay away from in a 2003/2004 model Silverado/Sierra to avoid major headaches, considering a may be swapping other parts over as well ?

[DmaxMaverick]

I think when MP said the 2500/3500 frames were wider, he meant 2500HD/3500. The reason is, this is primarily a GM Diesel site, and the late 2500's (1999+ GMT-800) did not have an available Diesel. The Duramax is/was only available in the 2500HD and 3500 (and the 4500/5500). The late model (GMT-800) 2500's are only available with a 6.0L gasser. The 2500HD and 3500 are available with the Duramax, 6.0L and 8.1L. The 1500HD was only available with the 6.0L gasser, while the 1500 can be had with the 4.3L, 4.8L, 5.3L, 6.0L (Denali, C3 and Caddy), and now the 6.2L gasser in the Denali, C3 and Caddy. That's not the end of the story, but enough for now.

Still confused? It's not my fault. GM did it. Not me........

You can stuff a Duramax into anything........given enough time and $$. It will fit into any full size GM truck. The problems surface with accessories and making the engine talk to the rest the truck, and vice versa. It's all workable, though.

[HCB]

You can stuff a Duramax into anything........given enough time and $$.

Like how they shoehorned a twin-turbo Vette motor into a Pontiac Solstice Roadster. There's a pricey horsepower to weight ratio that will likely get some yahoo killed.

It will fit into any full size GM truck.

Ah, well now that's encouraging.

So what is the purpose of the wider frame ? To accommodate the 8.1L big block ?

The problems surface with accessories

Such as ?

and making the engine talk to the rest the truck, and vice versa.

I assume transferring the dash and harness along with the computer helps.

[More Power]

The "wider front track" for the 2500/3500 mention earlier was based on what I've read about the GM pickups. I suppose the wider track is due to heavier/higher-rated front suspension and axle components. I doubt engine fit is a factor. In the early 90's you could order a Chevy SS 1500-series pickup with a big-block, and the 90's 1500-series pickups/SUVs were available with the 6.5L TD.

I saw Arlie's conversion 1993 K3500 CC SRW project last week. It'll be cool once complete. In addition to the body lift, Arlie modified the motor mounts to raise the engine a bit. This is part of why he didn't have quite as much interference between the oil pan and the front axle mount assembly.

The problems surface with accessories and making the engine talk to the rest the truck, and vice versa. It's all workable, though.

Things like ABS, HVAC, airbags, wipers, cruise control, etc.... All except for ABS are covered in the conversion guide.

Jim

[HCB]

The "wider front track" for the 2500/3500 mention earlier was based on what I've read about the GM pickups. I suppose the wider track is due to heavier/higher-rated front suspension and axle components. I doubt engine fit is a factor.

Good. Good. Good.

If the wider frame is not an integral issue, then it should be fairly straightforward, as I've done lot's of swapouts and conversions over the years.

Things like ABS, HVAC, airbags, wipers, cruise control, etc.... All except for ABS are covered in the conversion guide.

I saw that. As soon as I find the right truck, that's one of the first things I will be ordering.