05 LLY into 99 RCSB 1500

[thunder550]

I've got a project going right now to put the complete drivetrain, interior, and electrical from an 05 donor into a 99 half ton RCSB.

The current plan is to do a 2" body lift to clear the LLY cooling stack, run the 1/2 ton 8.25 front axle, and do a 9.5 SF rear end.

I bought the 99 back at the end of Feb, started tearing it down at the beginning of March, and picked up a LLY donor about 2 weeks ago.

Here's the progress to date:


99 loaded up for the ride home

Teardown started

Body removed. This took about 4 hours...wish I had a lift!!

Chassis rolled out from under the body

Donor made it home after a 35 hour round trip from Denver to Houston. If I never get the chance to do that trip again, that's ok!

05 dash frame installed in the 99

Starting to look like an 05 LT interior

XM and Onstar antennas mounted to the 99 cab roof

The overhead temp sensor for the auto climate controls doesn't fit under the 99 headliner. Not a big deal, the 99 headliner is pretty nasty anyway. When I'm done with the rest of the truck I'm going to look for a headliner and a few other trim pieces from a reg cab truck with the auto climate controls. This is the only part that didn't go together smoothly....

...and the 99 LS has been converted to a 05 LT interior!!

Here's a preview of my EXCITED face when this project is complete B)

That's where it sits right now. I have the front end of the donor LLY torn down in my driveway, hoping to be able to pull the driveline by this weekend. I want to power wash the 99 frame and see if I can clean it up a bit, swap fuel tank and chassis wiring, then it'll be about time to get that LLY/Allison to it's new home in the 1500 frame! More to come!

 

[TheBac]

I see you made it over here. Better add to the performance budget now....its truly a sickness. :roflmao:

 

[duratothemax]

Looks great!! Nice job converting the truck to the LT interior!

Although there was/is no such thing as a regular cab with auto climate control from the factory. So you'll have to do something custom there to make the auto climate temp sensor fit in the regular cab headliner.

ben

 

[thunder550]

I see you made it over here. Better add to the performance budget now....its truly a sickness. :roflmao:

Ahhh I know! This is the CHEAP part too...once I start turning up the power is when it will get expensive :woott:

Looks great!! Nice job converting the truck to the LT interior!

Although there was/is no such thing as a regular cab with auto climate control from the factory. So you'll have to do something custom there to make the auto climate temp sensor fit in the regular cab headliner.

ben

Thanks for the info on the RC...was not aware of that. I'll figure something out...maybe I can trim out some of the headliner backing to make it fit better. Minor detail compared to the rest I suppose.

 

[THEFERMANATOR]

You could probably swap the 9.25 front axle in as well. Not sure on the newer trucks, but I know on the 88-98 platform you could swap them in.

 

[thunder550]

I've done a lot of searching about the 9.25 and they are a PITA to swap. The only ones I've seen done are on lifted trucks, and the owners had a hell of a time. It essentially involves removing ALL of the front diff brackets and welding on custom ones, and even after that, the geometries of the control arms and CV joist still don't match. I believe the 9.25 in the GMT800 trucks is wider than the 8.25's. Too bad GM couldn't make it an easy swap like on the GMT400's.

At least with the 9.5 SF out back and the 8.25 up front I'll be able to run 6 lug wheel all around...those are easier to find and a bit cheaper. I thought about running the 11.5AAM out back, but I think in a 4wd the 9.5 will survive and save a little bit of weight too. I am assuming that I'll be able to find one though...I guess they are hard to come by.

 

[DURAMXD]

You guys and your Duramax swaps into RCSB 1500s are KILLING me! :thumb:

 

[TheBac]

Search car-part.com for the rear axle. You can also find them on Craigslist if you search 14 bolt.
If you cant find the disc brake "hybrid" axle out of the mid-2000s Silverado SS, try to find an axle with the small rectangular brake drum perches. Cheap and easy to buy/install disc brakes using aftermarket bracketry on those axles. I have a disc-brake axle out of a 2001 3/4ton truck (8 lug). The perches are oddball and it wont work with my 6 lug axles as it sits. Found out about the different perches after the fact.

 

[Chevy1925]

how id love to put my motor in one of these.....


damn it i got too many projects. Lookin great though!!!

 

[hondarider552]

how id love to put my motor in one of these.....


damn it i got too many projects. Lookin great though!!!

Cut my frame and it could be a rc/sb

 

[Chevy1925]

Cut my frame and it could be a rc/sb

yeah but on a 2500 frame

 

[TheBac]

Cut my frame and it could be a rc/sb

Any of you guys taking a trip to Michigan any time soon? I may just scrap my 1500 plans.
Ive got that 2500 you can cut. Then I can just put the red body on it.

 

[THEFERMANATOR]

Eric at DURABURB does the 9.25" swap into them with the DURAMAX, you could try asking him what all is involved in it as he's done quite a few now.

 

[DURAMXD]

Any of you guys taking a trip to Michigan any time soon? I may just scrap my 1500 plans.
Ive got that 2500 you can cut. Then I can just put the red body on it.

How about I come up and shorten your 2500HD donor truck and I'll take the 1500 home with me?

 

[TheBac]

I dont think that'd work, because its in pieces in/behind the garage. :rofl:

Sorry for the derail, Thunder.

 

[thunder550]

LOL, no worries :thumb:


Got the driveline pulled this afternoon. What a bitch! The wheels on my cherry picker started sinking into the asphalt since there was so much weight. The beast is finally in the garage with the neighbor's help.

Finally got to take a look at the motor mounts. The driver's side is in the same position on both the 1/2 ton and 3/4 frames, but the passenger side sits about 3" further forward on the passenger side. I was planning on running adapter plates to get the LS mounts to bolt up to the Duramax, anyone have thoughts on whether or not I can just make up that 3" difference in the adapter plate? Or am I going to have to cut and weld the 1/2 ton frame pad?

1/2 ton frame, the two frame pads are the same distance from the front of the truck:

3/4 ton frame...the passenger frame pad is forward of the driver's side by about 3"

 

[THEFERMANATOR]

Eric at DURABURB uses a piece of 3/8" plate to move the passenger side mount up to match. You may be able to find some pics of it at DP in his posts.

 

[thunder550]

Made some progress today, and ran into an issue.

First...adapter plates. I cut the driver's side first for both the block side and the LS mount side. Here it is bolted up. Tight clearance.

Had to grind down a bolt hole riser on the block to fit the head of the bolt that goes through the extra hole for the LS mount:

Here is the passenger side bolted up. I didn't drill the holes for the LS mount yet because I wanted to see where it ended up lining up when the engine was set in place:

Here it is resting against the LS mount, which is bolted to the frame in this pic

Now the problem I ran into...when the passenger side is sitting flush like in the pic above, there is about a 3/4" gap between the driver's side motor mount and intermediate mount. I'm not quite sure what to do about this. Any suggestions? Can I just move the mount down on the adapter plate? Did any of you other swappers run into this issue? I checked underneath and the oil pan looks level, so I think the engine is sitting in the correct position on the frame but I can't get bolts started with the driver's side mounts lined up like this.

 

[thunder550]

I ended up having to remake the driver's side adapter plate. Here's what they ended up looking like. I took the bottom two holes off the driver's side plate, it was too long and wouldn't fit correctly.

I'm having an issue with the front diff support bracket bolt, it's rubbing the edge of the oil pan, even after I ground it almost flat. Gave up on fixing it tonight, will try again tomorrow.

And here's how I'm sitting right now. It's not bolted down, but the motor mount holes line up with the intermediate mount holes. Just need a solution to that bolt head that's rubbing the edge of the oil pan.

 

[TheBac]

Carriage-type bolt for the mount (flat rounded head)? Modify oil pan to clear it (ask FERM for a pic of his pan)?

Looks like the motor mounts werent so easy to mod after all. That looks like a good 1-inch difference. Damnit, that sucks.
You do realize you're the first person who's ever actually posted what it takes for the mounts. Everyone else who's done one before treated all the info like a damn state secret.