2wd to 4wd conversion

[Dazedandconfused]

Not exactly a repower but close. Has anyone done this? I'm tired of getting stuck around the farm and dont want to sell my truck. I have a complete front end out of a 97 2500 are they the same? I know there are a few tabs or mounts that need to be added but does anyone have any pics of this?

Thanks
Andy

 

[duratothemax]

the GMT-400 front ends are all different...as is the 4wd actuator. Forget using the 97 front end stuff in your dmax.

you will need actual GMT-800/900 HD 4wd parts...yes...if you got ALL the parts, ALL the wiring, ALL the components and ALL the computers/actuators...sure its possible and it would work fine.

Is it worth it? Its been discussed 1,000,001 times, and the answer is more or less no. Way more cost effective to just trade it for a 4wd truck...I know thats not the answer you want to hear though.

ben

 

[Dazedandconfused]

I have very little in the truck now. I have access to a wrecked truck for parts so thats not a big deal. I could careless about the pushbutton 4x4 as well. I'd rather have the floor shifter. This truck wont go so if it comes down to it I'll just but my brothers BB and run it to.

 

[duratothemax]

I have very little in the truck now. I have access to a wrecked truck for parts so thats not a big deal. I could careless about the pushbutton 4x4 as well. I'd rather have the floor shifter. This truck wont go so if it comes down to it I'll just but my brothers BB and run it to.

the floor shift 4wd still requires a computer, wiring, etc...

 

[Dazedandconfused]

This is why I miss my Dodge and Ford.

 

[SmokeShow]

Search around in the mikeL trans section andy, there's a good thread in there that I started for converting my 06 to 4wd from 2wd. I'm lazy and don't feel like typing it all out but maybe we could meet up and chat about it. I've acquired almost all physical parts sans the xcase and any wiring necessary to make it work. The elect. side of things has been the hardest thing for me to get answers on. I'm pretty sure there are some that know the elec. system enough to help but I haven't got all the info. out of them yet. Probably just a money thing, haven't spent money with those in the know yet.

Shoot me a pm with a number. We need to have a KYDTR get together anyways... been too long.


C-ya

 

[bullfrogjohnson]

Straight axle it:thumb:

 

[Dazedandconfused]

I found that thread Mitch was just to lazy to look threw it. I may just leave it and buy the BB for when i need 4x4. Getting lazy anymore I guess.

 

[THEFERMANATOR]

the floor shift 4wd still requires a computer, wiring, etc...

Which ones is that? I know that I don't have one in my swap, just hooked up the transfer case switch to the front harness and it worked. Then hooked up the wire for 4 low and 4X4 for the ECM.

 

[SmokeShow]

ok, I lied.... I'll try to list as much as I can remember without looking back through notes...


Front end: Need 4wd hubs, half shafts/cv shafts, and front diff. Think there's two mounting points on the driver's side. Think one is in the crossmember but can't remember for sure on their locations. Then on the pass. side there is a bracket that bolts to the frame and the diff mounts to it. You'll either need those things or fabricate your own. for mounting the diff.

Transmission: best bet is to sell your 2wd transmission and buy a complete 4wd unit. Most say the only difference in the two is the tailhousing and output shaft but I'm thinking Mike L. said the planetaries might be diff. also. So yeah, I'd just get a 4wd trans. and sell the 2wd.

Obviously you'd need to buy a transfer case. 263XHD is the elec. shift version and the 261 is the manual shift version. If you went with the 263, it's actuation elec. run through the BCM so you'd need one from a 4wd as I don't think they can be flashed to work in a 4wd. If you go with 261, I *think* your BCM will be fine as-is. Either way, you'll need wiring back to the ECM and TCM that will tell them when the xcase has been shifted from 2wd to 4HI or 4LO and subsequently switch shifting tables it uses. The front diff. is elec. actuated via a ground wire when shifted into 4wd. You can get a manual lock-in (Posi Loc brand is the one I'm familiar with) and eliminate the need for that wire but it's the easiest wire to take care of so either is easy enough. :rofl:

Tuning: is as simple as a flash with appropriate OS tunes.

You'll also need to get a front drive shaft and shorter rear shaft. Can't remember for certain but I'm thinking the transmission crossmember is the same and might not even have to be moved since the xcase just kinda "hangs" off the back of the alli.???

There's also the option to go SFA. That doesn't make it any easier though IMO because all the wiring except the simple ground wire to the front diff. actuator has to be done plus all the fabricating to mount the sfa cause I know you're not going to buy a $5K kit. I'm also thinking you have to put in a SLE (slip yoke elimination) kit in the xcase for the sfa IIRC.

To get it all like the factory would probably be a nightmare. To get it to just work is more doable.


Good luck bud. Honestly, I wouldn't do it. Second truck or trade would be the better choice IMO.

 

[duratothemax]

they dont make a manual posi-lock setup for the GMT-800's.

 

[SmokeShow]

you're right, but one for a 98 and older can be made to work really easily. I know because I've seen it done.

 

[SgtKilroy]

Straight axle it:thumb:

x2

If you can find a Dana 60 front axle from a 79 Ford F250/350, transfer case (and yes a slip yoke eliminator kit), fabricate some leaf spring mounts (ballisticfabrication.com) and leaf springs from a 99ish Ford Superduty (52" IIRC), the solid axle swap is pretty straight forward. You will also need to shorten up your rear drive shaft approx 6" depending on your suspension height, and get a longer front drive shaft. There's even the option to go coil springs which will free up a bit more turning radius, but you'd be looking at a 4 link for the front end. The problem with SFA conversions is that unless you go with a newer Dodge D60, you will lose your front ABS. Just another annoying warning light unless you tow heavy. Then you definitely want the control should you have to hit the brakes hard. One big thing, is that when you're setting up your pinion angles for both axles, make sure the angles are the same or are within 3 degrees of each other. Any more severe angles than that and you will start running into issues with driveshaft vibration. One possible solution to that though is to look up a company called high angle driveline. They specialize in high angle drive shafts. Pricey, but worth it if you need it.
Either way, good luck! 4x4 is definitely the way to go.:thumb:

 

[THEFERMANATOR]

you're right, but one for a 98 and older can be made to work really easily. I know because I've seen it done.

Yep, the actuator that they sell to retrofit the older GMT-400 is the same one that is in the front end of my 01 donor truck. The older trucks(97-) use a longer actuator though than the newer ones do, hence the aluminum spacer you have to install in the older trucks when you retrofit the new style electric one.

 

[Burn Down]

Solid front axle. Divorced np 205 transfer case. That would eliminate most of your electrical problems, and be very stout on the farm.

 

[SmokeShow]

Solid front axle. Divorced np 205 transfer case. That would eliminate most of your electrical problems, and be very stout on the farm.

How do you propose that would eliminate any need for electrical modifications? A signal will still have to go to the ECM/TCM to let them know when the truck has been engaged in 4wd so they can use the appropriate tables in the tuning for 4wd mode. If going to a remote transfer case, while it might not be 100% necessary to get the truck to function in 4LO without it, it'd be best (and not a jerry rigged setup) if you get the speed sensor POST transfer case just like it is in the gm800-900 trucks. Again, that way the computers know when to tell the transmission to shift properly.

The only thing electrical that would be eliminated that way is the ground wire that controls the actuator on the front IFS diff. which we've already discussed can be done easily or done away with entirely with a Posi Loc kit.



So, NO. I'm convinced that going SFA will actually be MORE work than converting his front 2wd IFS to 4wd IFS especially if you are talking about divorced np205 transfer cases. Doing the later (sfa w/ divorced 205) will require a LOT more fabrication just to mount the pieces and then have to retrofit electrical components to pieces that never had elec. components before. Anything is DO-ABLE though.


Now if he was willing to give up the alli in favor of a manual tranny, then I might give a little more lean towards SFA because then the hardest part would just be the mounting of the axle and xcase and it opens up some options on transfer cases depending on desired application of the truck. The ECM would never need to know if it was in 2wd or 4wd if it's a manual (although I'm thinking the manual tranny trucks DO still know when it's shifted into 4wd) and there is no TCM to speak of. The engine will run the same either way, and the man in the seat controls when and how it shifts; not a bunch of computers talking to each other coming up with what they think is the right time to shift based on too many sensors regardless of what the driver might be thinking is the right/ideal time. When they (the computers) are right though, they are a thing of beauty!!


C-ya

 

[Dazedandconfused]

I've also tossed around the Idea Mitch of converting it to a ZF6 speed. As much as I like my allison I still wanted a six speed when I got this one.

 

[Burn Down]

Is there special tuning for the truck when four wheel drive is engaged? What is it doing?
How would it be jerry rigged? Here is a link to truck that was done this way. Looks pretty clean and un jerry rigged to me...http://www.dieselpowermag.com/features/dodge/0605dp_2005_chevrolet_2500hd_duramax_diesel/photo_01.html

 

[JoshH]

Is there special tuning for the truck when four wheel drive is engaged? What is it doing?
How would it be jerry rigged? Here is a link to truck that was done this way. Looks pretty clean and un jerry rigged to me...http://www.dieselpowermag.com/features/dodge/0605dp_2005_chevrolet_2500hd_duramax_diesel/photo_01.html

There are some TCM and throttle position tables for 4lo, but I don't see that it is absolutely necessary to have them available. I see nothing wrong with doing it the way you said. The only possible problem I can see is when engaged in low range, the front ABS speed sensors will not read what the VSS is seeing, but if you do a SFA, you probably won't have front wheel ABS sensors anyway.

 

[SmokeShow]

You're right, that one appears to be done pretty well. I couldn't tell for sure but it looks like the vss is still on the tailshaft of the 2wd allison. If that's the case, I'm curious if or how his alli knows how to shift correctly when in 4wd and if or how his speedometer reads correctly when in 4wd.

I wasn't meaning to say that going with a SFA and divorced xcase was a jerry rigged setup. It certainly can be done and be done correctly. In fact, it can be done multiple ways. Of which, some will function as a 4wd, meaning all 4 tires will pull, but without the appropriate wiring, it won't function like it's a factory application - i.e. the shifting and speedo issues I asked about above. It's not that big of a problem to get one to go into 4wd physically. If it's not important for the speedo to read correctly or shift appropriately while in 4wd, then yep, there's not much to slapping a sfa under there or even getting the IFS system to work. Conversely, if factory-like function is desired to where all systems work just like a factory 4wd would when in 4wd, then it is a good bit more work to get it right as far as electronics goes.


And I realize it seems as though I was coming down on you in particular for your idea. I really didn't mean to. I simply quoted you to discuss the 2wd to 4wd via SFA in general, not to really address you personally on the subject. Sorry about that. What I'm trying to point out is that to do it right and make everything work correctly in 4wd (not just have all 4 tires turning aka jerry rigged) it takes a good bit of work and still requires all the same electrical stuff when talking about using the alli. The divorced xcase just adds another element of fabrication to it.


I don't have all the answers or else I would have already done this because this is what I was trying to do - convert a 2wd IFS to 4wd IFS. I'm 99% sure I'm forgoing that idea and going about it differently.