4L80E swap question...

[mitchedo]

I posted this in the transmission section yesterday, but I don't think that section is frequented by as many folks as this one.

The trans oil in my truck smells like a rotting corpse. I mean, it stinks terrible!

I have a 1991 Suburban V2500 sitting next to my truck in the driveway. The 4L80E in that one is hooked to a 350 in the front and a NP241C transfer case in the back. It was a brand-new dealer replacement in 1997, and has about 30,000 miles on it. I've owned the Burban since 1998.

My 6.5 only has 6 bolt holes at the back, so the top one in the trans is unused.

I would LOVE to swap the transmissions in those two vehicles, since I'm not likely to get much more than scrap for the Burban when I sell it.

My truck does not have a 241 transfer case. I don't know which it is, but it has a lever on the floor.

Would this swap work, electronically and physically?

 

[gmctd]

Not without some hassle - the electrical components in the valve-body changed from that first issue unit, which would damage yer 99 PCM - the 6.5 gets the largest-available torque convertor and other hd hard parts - why not do the logical thing, drop yer pan, note the stuff in the bottom, if not bad, change the filter and atf, go from there?

You should pull that early 4L80E, wiring harness and stand-alone TCM, sell the package - that's the same TCM and harness that B&M, TCI, and others sell with their hp 4L80e conversion package

FYI - GM has re-released that stand-alone TCM and wiring harness for the upgraded 4L80E, has a GM p\n, can be purchased across the counter or on-line

 

[mattthebrat]

I agree with gmctd, just change your filter and flush your tranny, then sell the 4L80E, you will get more for that then you could get for the rest of the burb.

 

[daustin]

I agree with gmctd as well, change the filter/fluid note what's in the bottom of the pan and drive it. I'd also do that again in like, 5 or 10K miles. I would avoid a flush, i've had bad experiences with those - i think that flushing stirrs up debris that's better left alone. The tranny/ecm/harness would be very easy to sell, anyone with an auto wanting to covert to a mechanical IP would love to have that combo. Among other things, they changed the way the lockup/TCC works to a PWM style from the older single wave type of clutch application. :smile5:

Don

 

[mitchedo]

That's all just the info I wanted to hear!

I might consider a transmission oil change, one of those that uses the transmission pump and just changes the fluid. But I'm not going to put any cleaner through it or let anyone back-flush or flush it with pressure. That's asking for problems with a trans that stinks as bad as this one.

So, the new, fancy-schmancy electronics they sell with the aftermarket 4L80E's for retrofitting older cars is pretty much what's in my Burban? If that's the case, then I'm keepin' it for my Chevelle! I'd love to run a 4L80 in it. I think that's worth more to me than what I'd get for the old Burban. ...guess I'll start watchin' for a new tail section, since the Chevelle would look pretty silly with 4x4 axles under it.

As for the truck, the pan will come off, I'll drain as much as I can. I should'a dumped out the torque converter before I put the engine back in. I'll change the filter at least once, and look for a place that can gently change the fluid for me. ...then I'll change the filter again. ...bolt it back up and run it 'till it dies.