4l80e conversion question

[l-eater]

This question is for anyone who has put a 4l80 in a Ty. I am to the point on my Blazer project where I tried to test fit the transfer case and I can't get it to fit. It won't clear the crossmember enough to go into place.

The crossmember I am talking about is the one that runs side to side along with the one for the torsion bar mounts. There is a body lip directly above that I can flatten and gain a little clearance but I am sure it still wont go. I don't see anyway for the T-case will fit without taking a sawzall to the crossmember. Anybody else ran into this?

 

[Black Knight]

Re: 4l80e conversion question

Not that I have any knowledge in this area, but I think I read you need to change the cross member for the 4L80E. If you look up George Blake's threads there one on the 4L80E, it might help.

 

[l-eater]

Re: 4l80e conversion question

Not that I have any knowledge in this area, but I think I read you need to change the cross member for the 4L80E. If you look up George Blake's threads there one on the 4L80E, it might help.

Thanks for the reply. Yes, you change the crossmember that supports the tranny-I bought the whole conversion kit that includes that crossmember. The crossmember I am talking about is farther toward the rear of the truck right next to the one that the torsion bars go into.

 

[JSM]

Re: 4l80e conversion question

If you bought kit from George, then you may have to install the trans and transfer case as 1 unit. Sometimes that is easier. Slide the rear up above torsion bar crossmember, and slide it all back and up, it is a tight fit but will fit.

 

[George Blake]

Re: 4l80e conversion question

Yep. Has to be installed as one unit. Converter must be secured so you can tip the front down and get the tail end of the transfer case over the torsion bar crossmember and then lift the front into place. The distance front to rear for the torsion bar crossmember and length of the torsion bars is the same on sy/ty/s-10 4x4 if that kinda puts it into perspective.

 

[ed hess]

Re: 4l80e conversion question

so what if you cut out the crossmember in the center and let the torsion bar crossmember be the only crossmember? seems to me 2wd trucks only have one of these so enough strength would be there.

not going to 4l80 but just thinking outloud...

anyone ever cut one out.

besides if you had to pull the transfer case it would then be a lot simpler than pulling the trans with it.

ed


ed

 

[JSM]

Re: 4l80e conversion question

If you go to coilovers you can remove the crossmember that causes the issue. I have done it and the install becomes VERY simple.

 

[mattw]

Re: 4l80e conversion question

Also, if you need to make sure that you have the correct tranny to x-fer-case adapter(not the 4l80e one but the stocker that goes behind it).. If you are using a regular 4x4 one it will clock the x-fer-case 8 degrees toward the floorboard and make it impossible to fit.. You need to make sure that you have an AWD one from a bravada, astro, or sy/ty..

-Matt

 

[myclone]

Re: 4l80e conversion question

so what if you cut out the crossmember in the center and let the torsion bar crossmember be the only crossmember? seems to me 2wd trucks only have one of these so enough strength would be there.

not going to 4l80 but just thinking outloud...

anyone ever cut one out.

besides if you had to pull the transfer case it would then be a lot simpler than pulling the trans with it.

ed


ed

Yeah the 2wd trucks only have the x member for the trans and the frames are plenty stiff. I took the torsion bar x member out of my truck when I went with the coil overs and it didnt affect torsional rigidity one bit (yes, I checked...long story but I couldnt measure any diff below 1/16" with the x member gone).

With the torsion bar x member out you can drop the trans and xfer case as one unit easily and the only thing in your way is the E brake cable. Its easily removed by taking it apart at the adjuster on the drivers side (one 13mm nut).

Be aware that not only is the x member for the torsion bars riveted in its also welded to the bottom of the frame rail. The rivets are easy to drill but breaking the welds lose is a PIA...I couldnt get any of my grinders in there so I just beat the crap out of it with a 10lb sledge until I broke the welds. Once the x member is out its easy to get to the welds to grind them off and dress things up. Word of advice is dont go at the x member with the sledge at 1am....it pisses off your neighbors.

 

[l-eater]

Re: 4l80e conversion question

Ok thanks guys. I knew it wasn't going in separately. I am off work tomorrow and I plan on getting some of this stuff finished up. I think I am going to study on the crossmembers a little but I may go ahead and hack at least some of it out of there. I will let you guys know if i cut it out.

 

['JustDreamin']

Re: 4l80e conversion question

I know exactly what you're talking about.....

I did the 6.0L / 80E swap into my '99 Bravada (including a NV246 tcase). I fought that crossmember (the frame to frame welded in place bugger right ahead of the torsion bar crossmember) and finally gave up on it.

I removed all but about the outside 6", made a set of plugs that I welded into the crossmember stubs, and replaced the center with a piece of structural channel ( I think it was 4" x 6.0lb / ft) with a set of ends welded to the channel. Now four 1/2" SHC bolts hold it together. I thought about removing the entire crossmember and making a new one that was removeable (like a trans crossmember) but decided to hack and chop on the existing one instead.

If you decide to alter the existing crossmember, make sure you get it REALLY REALLY clean before you try and weld on it. That stuff makes it damn near impossible to get a good weld, and burns real good too (I hate having to lift my helmet to blow out flames!)


BTW, keep us posted as to how the STS kit goes. I've talked to them about a kit, but decided not to worry about it for now. Need to get the truck fully functional first.


'JustDreamin'

 

[l-eater]

Re: 4l80e conversion question

I know exactly what you're talking about.....

I did the 6.0L / 80E swap into my '99 Bravada (including a NV246 tcase). I fought that crossmember (the frame to frame welded in place bugger right ahead of the torsion bar crossmember) and finally gave up on it.

I removed all but about the outside 6", made a set of plugs that I welded into the crossmember stubs, and replaced the center with a piece of structural channel ( I think it was 4" x 6.0lb / ft) with a set of ends welded to the channel. Now four 1/2" SHC bolts hold it together. I thought about removing the entire crossmember and making a new one that was removeable (like a trans crossmember) but decided to hack and chop on the existing one instead.

If you decide to alter the existing crossmember, make sure you get it REALLY REALLY clean before you try and weld on it. That stuff makes it damn near impossible to get a good weld, and burns real good too (I hate having to lift my helmet to blow out flames!)


BTW, keep us posted as to how the STS kit goes. I've talked to them about a kit, but decided not to worry about it for now. Need to get the truck fully functional first.


'JustDreamin'

I went over to my shop this morning and I stood there thinking about what George said-how you have to install the trans and the t-case as a unit and have to tilt the front of the tranny down a lot to get them in there. I dropped a 4l80e from the transmission jack a couple years ago......NOT a pretty sight !!! So I decided to hack the crossmember.

After a couple minute with the sawzall the T-case fit right in. I will make a bolt-in section after I get the motor/trans/t-case in for the final time.

I haven't even really looked at how I am going to mount or pipe the STS. The kit I have is for a late model ext cab truck so most of the stuff will have to be re-worked. I am planning on using the air to water I/C that I had on my 02 Silverado so there is lots of fabbing still to do.