CK5
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'89 R3500 Crew Cab 2wd to 4wd conversion & beyond

Started out with 2wd TBI350 with SM465 to current 4wd with 454, 700r4, NP241
It's not just the frame twist that kills that style engine mount, it's the torque multiplication too. All the torque going through your driveshafts is going right into those mounts, that's why you have to go with the suspension bushing style.
A stock engine mount won't last one trip on a rock trail.
 
I have been analyzing data from everything I could find in the past 20 years and with added data form my big rigs I came to the conclusion that the best way is to build a cradle to mount the complete running gear to solidly that will keep the stress off the mounting surfaces between parts, and suspending the cradle on three mounts, 2 front and one rear.
The motor mounts will work as is, we just need to secure the cradle to the engine in a strong way.
I am designing a system for my next project
 
I have been analyzing data from everything I could find in the past 20 years and with added data form my big rigs I came to the conclusion that the best way is to build a cradle to mount the complete running gear to solidly that will keep the stress off the mounting surfaces between parts, and suspending the cradle on three mounts, 2 front and one rear.
The motor mounts will work as is, we just need to secure the cradle to the engine in a strong way.
I am designing a system for my next project
That was basically my thought behind how I did the mounts in mine too. I did the 2 in-line under the tcase just because I didn't feel like 1 mount was enough. It was just a "feel" thing. In thinking about it, the only thing I could think could be done differently is to rotate the trans mount bushings 90° so it's parallel with the engine mount bolts. Not sure that'd make much difference, but it's a thought anyway.

I will say the bolts are loose like they would get with the 700r4/241. In that case it would loosen up enough to get a steady trickle of fluid and the last trip to Blazer Bash required almost daily retorque. On the current setup, I only noticed a drop of fluid and the bolts weren't very loose. It's taken 7 years (can't believe it's been that long) for it to crop up. I'd still like to do something to keep it from being an issue.
 
That was basically my thought behind how I did the mounts in mine too. I did the 2 in-line under the tcase just because I didn't feel like 1 mount was enough. It was just a "feel" thing. In thinking about it, the only thing I could think could be done differently is to rotate the trans mount bushings 90° so it's parallel with the engine mount bolts. Not sure that'd make much difference, but it's a thought anyway.

I will say the bolts are loose like they would get with the 700r4/241. In that case it would loosen up enough to get a steady trickle of fluid and the last trip to Blazer Bash required almost daily retorque. On the current setup, I only noticed a drop of fluid and the bolts weren't very loose. It's taken 7 years (can't believe it's been that long) for it to crop up. I'd still like to do something to keep it from being an issue.
What I am saying is that you need to brace the connection of the tcase to transmission with something externally and that will remove the stress from those bolts.
 
That was basically my thought behind how I did the mounts in mine too. I did the 2 in-line under the tcase just because I didn't feel like 1 mount was enough. It was just a "feel" thing. In thinking about it, the only thing I could think could be done differently is to rotate the trans mount bushings 90° so it's parallel with the engine mount bolts. Not sure that'd make much difference, but it's a thought anyway.

I will say the bolts are loose like they would get with the 700r4/241. In that case it would loosen up enough to get a steady trickle of fluid and the last trip to Blazer Bash required almost daily retorque. On the current setup, I only noticed a drop of fluid and the bolts weren't very loose. It's taken 7 years (can't believe it's been that long) for it to crop up. I'd still like to do something to keep it from being an issue.
I think i was talking with or read years ago with @Stephen at ORD and he said if builder bushings then best for bolts to ALL flow in the same direction. Otherwise under loads and flexing they can fight each other .
 
I think I found the answer to the bolt size question: 10mm 1.5 x 35mm.

This is based on a 4l80e adapter Advanced Adapters sells with the bolts.
 
If threads are bad, helicoil or full inserts or something (lots of brands and types available) to get good steel threads in it. Then fresh high grade bolts. Clean/degrease the holes and the bolts a lot. Check the back surface of the transmission for flat. Any humps in the casting will cause problems. Same thing with the adapter. Ideally, the adapter goes on a lathe to turn both surfaces true. The big deal right now is that it's flat so you have good even clamping pressure all around it. Locktite the bolts and torque them if you can reach them with a torque wrench. Otherwise, do what you can to calibrate your internal torquometer. At this point you could see if stage 8 has a fastener system for it so you have a mechanical lock but that's a "nice to have" in this case.
I don't hate your mount setup, if anything going a little stiffer wouldn't kill it but it's fine. You just want to make sure the motor mounts are stiffer than the t-case mounts so that engine torque is controlled at the source when you're not in low range. Your T-case mount system is trying to keep the cases from twisting off the back of the trans when it's in low range so they need to have some good torque holding ability but they can't be stiffer than the engine mounts. And if the bolts are staying tight for years, you just need to make them a little happier.
 
My sliders have been in need of revamp for some time. I've had to half cut them off to bend them down and reweld them once already, and it was time to do so again.

20250315_113422.jpg

The primary reason for this is that I couldn't weld much of the back side due to having saddle tanks when the sliders were originally installed. I figured now that those tanks are gone, I should redo the sliders.

My first thought was I should make the cab sliders line up with the bed sliders. However, I realized that would be a LOT of fabrication and complicated. It occurred to me I could kick up the back section of the sliders. This also ended up saving me from having to buy more steel because I could make each slider in 2 pieces. I used a level to get my angle and cut line.

20250315_133310.jpg

20250315_151509.jpg

Those are NOT my oil stains on the cardboard, that's from the F550 bucket truck. :frown1:

Anyway, the best part was the cut wasn't going to be in the door structure at all.

20250315_151516.jpg


I decided on 2x6 rectangle tube because it would get me a little more tube under the cab for better anchoring of the back side. I went with 1/4" wall since they are so wide and the truck is heavy. The new sliders are only about 18 pounds heavier per side. The bed has 2x5 sliders, but like I mentioned, I wanted more slider under the cab. Plus if I ever do a cage, the wider tube will be easier to tie into.

20250322_142102.jpg

Initial mockup above, the final installation has the slider tighter to the doors. Below is how my kick up ended up compared to the bed.

20250323_130200.jpg

You can also see above my big challenge or the part that is going to be the most work. I have a lot of gaps to fill. I'm using 1/8" flat strap to do it. It actually works better because it's quite difficult to weld sheet metal to 1/4" thick steel. The 1/8" thick strap does a nice job of sitting in the middle.

20250323_125930.jpg

This time I plated the back side of the sliders into the cab supports, I didn't do that before.

20250323_171038.jpg

20250323_171059.jpg

Now I just have a lot of welding to do filling in the gaps between the body and the sliders. Also still have the passenger side to do. :doah:

Here's a comparison of before and after. I guess the picture is actually after and before.

20250323_195004.jpg

If you look at the first 6" of the front door, you can see where I had to hack the bottom of the door to clear the old slider the first time it was bent up. @ktmoutfront might remember I had to borrow a cutoff wheel at the Chinaman Gulch trail head to cut that slot to be able to open and close the door.
 
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I like the kick up as well….might be worth it to get one of the slider tie in kits from ruff stuff and tie into the frame to prevent it from bending up again, then if you decide to do a cage just tie into it.

I remember when they built the UAK10 and did the slider similar to yours and they commented at the end of the trip how they couldn’t open the doors.

 
Kickup looks great and the design has nice overall flow to it. Form and function, intersecting.

David
 
My sliders have been in need of revamp for some time. I've had to half cut them off to bend them down and reweld them once already, and it was time to do so again.

View attachment 500391

The primary reason for this is that I couldn't weld much of the back side due to having saddle tanks when the sliders were originally installed. I figured now that those tanks are gone, I should redo the sliders.

My first thought was I should make the cab sliders line up with the bed sliders. However, I realized that would be a LOT of fabrication and complicated. It occurred to me I could kick up the back section of the sliders. This also ended up saving me from having to buy more steel because I could make each slider in 2 pieces. I used a level to get my angle and cut line.

View attachment 500390

View attachment 500389

Those are NOT my oil stains on the cardboard, that's from the F550 bucket truck. :frown1:

Anyway, the best part was the cut wasn't going to be in the door structure at all.

View attachment 500388


I decided on 2x6 rectangle tube because it would get me a little more tube under the cab for better anchoring of the back side. I went with 1/4" wall since they are so wide and the truck is heavy. The new sliders are only about 18 pounds heavier per side. The bed has 2x5 sliders, but like I mentioned, I wanted more slider under the cab. Plus if I ever do a cage, the wider tube will be easier to tie into.

View attachment 500387

Initial mockup above, the final installation has the slider tighter to the doors. Below is how my kick up ended up compared to the bed.

View attachment 500385

You can also see above my big challenge or the part that is going to be the most work. I have a lot of gaps to fill. I'm using 1/8" flat strap to do it. It actually works better because it's quite difficult to weld sheet metal to 1/4" thick steel. The 1/8" thick strap does a nice job of sitting in the middle.

View attachment 500386

This time I plated the back side of the sliders into the cab supports, I didn't do that before.

View attachment 500384

View attachment 500396

Now I just have a lot of welding to do filling in the gaps between the body and the sliders. Also still have the passenger side to do. :doah:

Here's a comparison of before and after. I guess the picture is actually after and before.

View attachment 500392

If you look at the first 6" of the front door, you can see where I had to hack the bottom of the door to clear the old slider the first time it was bent up. @ktmoutfront might remember I had to borrow a cutoff wheel at the Chinaman Gulch trail head to cut that slot to be able to open and close the door.
Looks awesome! Needs tied into the frame
 
Looks good! Did you do that backside yet? I would run strap along that to cover the gap and butt it up to the 90 by the spot welds and just overlap it on the slider a little.
 
I've had the same issues with my 2x4 sliders as @mrk5. They were installed about 7 years ago but I had to trim my drivers door this past fall after the summer of wheeling and landing hard on my sliders. Admittedly, I like to land on them and use them as a pivot point for some obstacles. My cage (A-Pillar) and frame is tied to the front of the slider so I'm not convinced frame tie-in's would eliminate this issue. However, I've found the cutoff wheel is quite effective at fixing the problem.
 
Kickup looks great and the design has nice overall flow to it. Form and function, intersecting.

David
Looking at it now, I'm thinking I should have kicked up the section under the front fender too. :thinking: :rotfl:


I like the kick up as well….might be worth it to get one of the slider tie in kits from ruff stuff and tie into the frame to prevent it from bending up again, then if you decide to do a cage just tie into it.

I remember when they built the UAK10 and did the slider similar to yours and they commented at the end of the trip how they couldn’t open the doors.

My original plan was to tie to the frame, but the general consensus was that I'd tear up the body without also having the cage.

I should have gained at least 1/2" of height and these don't stick out as far as the old ones. I'm hoping that will help minimize some of the impact on them. The worst one was the time I had to borrow the angle grinder from @ktmoutfront and that was totally me not paying attention. I had stopped in front of a big boulder and by the time we were moving again, I forgot it was there. I proceeded to drive over and SLAM down on it. It hit so hard I literally had a headache for quite a while.

It's also obvious it's the driver side I have trouble with because my body weight is always there so I've also gone on a diet plan. :haha:


Looks good! Did you do that backside yet? I would run strap along that to cover the gap and butt it up to the 90 by the spot welds and just overlap it on the slider a little.
Not yet. To be honest I'm not looking forward to all that overhead welding, but you did outline my plan. After looking at it more, I realize it at least needs covered to keep all the mud, dirt, and snow from getting packed in there.

I'm also contemplating welding up a few short sections strategically spaced apart and then using some of our industrial panel glue to cover up the rest of the gaps. Or another though is to drill holes in the overlapping piece and weld it in place with "rivet" welds into the rocker and slider.


I've had the same issues with my 2x4 sliders as @mrk5. They were installed about 7 years ago but I had to trim my drivers door this past fall after the summer of wheeling and landing hard on my sliders. Admittedly, I like to land on them and use them as a pivot point for some obstacles. My cage (A-Pillar) and frame is tied to the front of the slider so I'm not convinced frame tie-in's would eliminate this issue. However, I've found the cutoff wheel is quite effective at fixing the problem.
I do think it might be a bit of a hopeless cause trying to keep the sliders from bending up. I noticed when cutting the old one off, what's left of the rocker has actually been collapsed down. In the picture above with the flat strap I've started to weld into the door opening, the front area near where the end of the flat strap is was the most crushed in. I'm hoping the flat strap additions will help give it a little more rigidity. In addition, the original sliders weren't welded to the area behind the front fender where that big bolt is for the bottom of the fender, I actually had the slider notched out around that area to keep the lower fender bolt usable. This time around I'm going to makes sure that area gets welded to the slider so the front isn't just "floating" out there.

I don't really intentionally use the sliders much. Part of that is because they've been compromised and I knew it wouldn't take much for them to bend up. I landed on the driver side pretty good this past year on the Utah trip and I had to grind down part of the slider to clear the door. While it was loaded on the trailer I used a ratchet strap between the slider and the trailer to pull the slider back down a little ways.
 
Had a thought. Instead of tie-backs to the frame I could add some triangulation back to the cab supports on top of the body mounts. Like the sketch.

20250324_131523.jpg
 
If you guys look back two pages there was a discussion about wether to tie the sliders to the frame or not.
Why would we do this?! Pfft
My original plan was to tie to the frame, but the general consensus was that I'd tear up the body without also having the cage.
While true, won't your current setup make ti worse?
 
Well it shouldn't be worse. At this point, the worst outcome would be the same results.
 
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