I am in the process of planning a conversion of my van to 4x4, and need a few thoughts. I've read posts on this site for years, but never had a need to post...until now.
Vehicle - 2005 GMC Savana 3/4 extended van (now, before everyone posts that Fords are a lot easier to convert, which they are, the GMC has advantages over the Ford for me. This van is a motorcycle race van, so has already been setup or that purpose, which costs a lot of money. In addition, the GMC is about 5 inches higher in the cargo area, so a bike will slide right in without compressing the forks first. Finally, I own this one, and it only has 60,000 miles on the clock, and has been well taken care of, so I know the condition. Also, the factory 4x4 did not come in an extended van, so I must convert to get the extended van length)
Use - This is a road rig, and we travel a lot to races, so the 4x4 is for snow covered road, muddy roads getting into and out of back country race sites (I race long distance endurance events, so the pit crew often needs to get to me using one lane logging roads in awful conditions). Also, I don't really carry much weight, just two bikes and four people.
The planned Build - This is a build on a budget, so no sexy suspensions this time. Will use the leaf springs that I purchase with the axle, with a possible new main leaf if needed to center the axle. This will also make the axle install a one weekend project.
Front Axle - I have been looking at Dana 44 fronts, but today have been wondering why I can't just use a GM 10 bolt front from a 3/4 ton. This is my first question, essentially, is the any reason I should avoid a GM front axle since I do not plan to run high steering. Lower rig equals better fuel mileage.
Gear Ratio - I will have to swap gear ratio in the rear to match the front, so if I use a GM front axle, I can easily find a 3.73. This means I can use the same carrier in the rear instead of purchasing a new carrier to swap to something close to the 4.10 that comes in most Dana 44 front axles.
Steering - Stock steering gets tossed, as it will not work unless I use a Dana 44 with a high steer arm to keep the drag link above the springs. Since this is a road rig, no reason for high steering. I will have to notch the cross member below the steering box to install a drop pitman arm, as the current pitman arm curves up 2 inches and has the joint built in. With the drop pitman arm, I will box the cross member to retain strength. I will use the stock drag link and tie rod end from the axle I use, so nothing special here. The lift will be as small as possible, so drag link angle should not be a problem.
Front axle hanger - This one is easy, just build frame plates that will support on inner/outer frame, bolt, weld, and install the front of the spring. Might have to move the spring pad on the axle, but I have done this a lot, so no problem. Rear of spring will require a new cross member, as the frame is wider in the rear than in the front. New cross member is easy to build, and will give me a spot to hang my spring eyes for the rear shackles.
Brakes - Will use stock on the axle, so no big deal here. Just longer hoses, and maybe fresh brake components
Rear Axle - lift blocks, probably about 2 inches, and longer u-bolts. Simple.
Transfer case - I will use a divorced unit, NP 205. With the extended van, drive line angles are not a problem, so will use a short drive line between stock tranny and transfer case. I want to keep the stock tranny, as I have learned over the past 30 years of doing conversions that I want to keep as much as possible in stock form. As long as I properly support the transfer case, and include strut rods, I should avoid issues with transfer case movement. New drive lines to front and rear axles. This is probably the easiest part of the build because of the divorced transfer case. The linkage will just have to be designed on the fly.
I know this is a ton of information, but I wanted to provide the entire project in summary in order ask about using a GM 10 bolt front end instead of a Dana 44. Knowing that I don't need the high steering other details are an important aspect of the decision.
So, post up your thoughts.
Thanks
Rick
Vehicle - 2005 GMC Savana 3/4 extended van (now, before everyone posts that Fords are a lot easier to convert, which they are, the GMC has advantages over the Ford for me. This van is a motorcycle race van, so has already been setup or that purpose, which costs a lot of money. In addition, the GMC is about 5 inches higher in the cargo area, so a bike will slide right in without compressing the forks first. Finally, I own this one, and it only has 60,000 miles on the clock, and has been well taken care of, so I know the condition. Also, the factory 4x4 did not come in an extended van, so I must convert to get the extended van length)
Use - This is a road rig, and we travel a lot to races, so the 4x4 is for snow covered road, muddy roads getting into and out of back country race sites (I race long distance endurance events, so the pit crew often needs to get to me using one lane logging roads in awful conditions). Also, I don't really carry much weight, just two bikes and four people.
The planned Build - This is a build on a budget, so no sexy suspensions this time. Will use the leaf springs that I purchase with the axle, with a possible new main leaf if needed to center the axle. This will also make the axle install a one weekend project.
Front Axle - I have been looking at Dana 44 fronts, but today have been wondering why I can't just use a GM 10 bolt front from a 3/4 ton. This is my first question, essentially, is the any reason I should avoid a GM front axle since I do not plan to run high steering. Lower rig equals better fuel mileage.
Gear Ratio - I will have to swap gear ratio in the rear to match the front, so if I use a GM front axle, I can easily find a 3.73. This means I can use the same carrier in the rear instead of purchasing a new carrier to swap to something close to the 4.10 that comes in most Dana 44 front axles.
Steering - Stock steering gets tossed, as it will not work unless I use a Dana 44 with a high steer arm to keep the drag link above the springs. Since this is a road rig, no reason for high steering. I will have to notch the cross member below the steering box to install a drop pitman arm, as the current pitman arm curves up 2 inches and has the joint built in. With the drop pitman arm, I will box the cross member to retain strength. I will use the stock drag link and tie rod end from the axle I use, so nothing special here. The lift will be as small as possible, so drag link angle should not be a problem.
Front axle hanger - This one is easy, just build frame plates that will support on inner/outer frame, bolt, weld, and install the front of the spring. Might have to move the spring pad on the axle, but I have done this a lot, so no problem. Rear of spring will require a new cross member, as the frame is wider in the rear than in the front. New cross member is easy to build, and will give me a spot to hang my spring eyes for the rear shackles.
Brakes - Will use stock on the axle, so no big deal here. Just longer hoses, and maybe fresh brake components
Rear Axle - lift blocks, probably about 2 inches, and longer u-bolts. Simple.
Transfer case - I will use a divorced unit, NP 205. With the extended van, drive line angles are not a problem, so will use a short drive line between stock tranny and transfer case. I want to keep the stock tranny, as I have learned over the past 30 years of doing conversions that I want to keep as much as possible in stock form. As long as I properly support the transfer case, and include strut rods, I should avoid issues with transfer case movement. New drive lines to front and rear axles. This is probably the easiest part of the build because of the divorced transfer case. The linkage will just have to be designed on the fly.
I know this is a ton of information, but I wanted to provide the entire project in summary in order ask about using a GM 10 bolt front end instead of a Dana 44. Knowing that I don't need the high steering other details are an important aspect of the decision.
So, post up your thoughts.
Thanks
Rick
