05 gmc 4l60e swapped into 03 chevy 1500

[1968k10blue]

Been a while since I have been here, but long story short, I wrecked my 05 gmc and bought an 03 chevy. the chevys transmission is in need of attention, and I can't afford to have it rebuilt at the moment. I still have my old gmc in which the trans is just fine, and I was wondering if there might be anything that will get in the way of the swap.

Both trucks are basically identical, the gmc is a 4.8 4x4 w/ manual shift transfer case. The chevy is a 5.3 with the same options. From what I have read thus far, it seems like it will work fine, but I figured I would check here before I start getting my hopes up. Thanks to anyone who can give me insight to this!

[hatzie]

Should work just fine. I assume it''s a 4L60E or 4L65E
You can use the lower mile transfer case as well.

Blow out the cooler lines and install an inline filter in the return from the cooler so you don't bork the replacement with the kibbles N bits from the dead soldier.

[1968k10blue]

Hmm good call on that filter, didn't think about that. I assume both are 4l60e, but honestly I didn't know they put 65e's into these trucks. You have any info on that? just out of curiosity that is.

[1968k10blue]

oh, and another question that somewhat pertains, I want to swap out my diff, the old truck had the locker, which I absolutely love, and obviously the new one does not. they are different gear ratios, so I know I will have to swap ring gears, which isn't too bad. But the question I have for that is the shims. I believe if I am thinking about this right, the shims should be fine as long as they stay with the housing they came from right?

[hatzie]

My cousin and I blew up a couple really decent used transmissions back in the early 80's because we didn't clean out the cooler loop in the radiators.

GM put the 65E in some of the Suburbans. Not sure about the pickups.

If you change the ring and pinion you will have to setup the axle... even if you swap the diff over with the gear attached. Used gears are "worn in" to the diff and axle housing they live in. The pinion will not run at exactly the same angle and depth as the gearsets' original home. I wouldn't swap the gears from one axle to the other in a truck you intend to keep. They tend to wear rapidly when moved to a new home.

If the matching front axle in the rust bucket is good I'd install it in the new truck along with the rear axle from the same truck. Then the gears will match.

You will need to program the ABS and PCM to match the installed axle ratio and tire size. ABS is a Tech2 operation. You'll need a tuner package to take care of the PCM.
You should clear any "learned" information from the PCM. Generally unhooking the battery for more than a few minutes will do this. It'll regenerate the tables from the way the engine and transmission etc work together after a couple hundred miles.

[1968k10blue]

Okay, that sounds about right. Any recommendations on the filter? Its a z71 package on the new truck, so that might make it easier to find a place for one, but i would have no clue where to even start looking for a place to put one.

As far as the diffs go, I was originally going to just swap out the whole rear axle, but the different ratios made that a hard pass. It was going to be difficult enough to swap brake systems, since the old one was rear drums, but to add swapping out the front diff too would just make it way too much work for a winter project with no other daily driver or heated garage space haha.

So lets say theoretically, I go ahead with the carrier swap. Do you think I would make it through winter (maybe 8k miles)? Or would that be a stretch? If I had the funds I would just get myself a new set of gears, but that is just not an option for me right now.

[hatzie]

Just run the open diff this winter and swap both of them over in the spring if you can't live without the limited slip.

The metal can Magnefine filter is the inline filter I use on all of my Automatic transmission rigs. The plastic body filters that say Magnefine are counterfeits. Get a transmission pan with a drain plug or weld a bung in your pan and change the strainer as well. Change the inline filter in 500 miles and again at the next three engine oil changes to clear out any crud in the oil cooler system and transmission. After that I'd change the inline transmission fluid filter every two oil changes and the fluid in the pan at twice that interval. You shouldn't have to ever change the strainer in the pan since it's 110 microns and the Magnefine is 25 microns.
https://www.amazon.com/Magnefine-Mag.../dp/B0787KWZPS

[whitedog76]

I seem to think there may be a difference in the wiring harness. I think there is a break around 04.