Transmision Swap Yukonxl

hondaracer · October 28, 2009

i have a 2002 YukonXl and i want to beef up the transmision or get a different transmision for towing. it currently has the stock automatic and the 5.3 LS small block. i do have a budget and cant spend 4 grand on a new tranny. anyone have ideas? I would greatly appreciate any advice.

trigen7 · October 28, 2009

i have a 2002 YukonXl and i want to beef up the transmision or get a different transmision for towing. it currently has the stock 4L80E automatic and a 5.3 LS small block. i do have a budget and cant spend 4 grand on a new tranny. anyone have ideas? I would greatly appreciate any advice.

The 4L80E is already a beefed up tranny. Are you positive you have the 4L80E and not the 4L60E?

I have the 4L80E in my 3500 and it tows like a champ! I did however install an aftermarket transmission oil cooler though. The one that came on the truck is good don't get me wrong, but I tow alot and wanted to have the extra piece of mind of a bigger cooler. I also added a transmission temp gauge too just so I can keep an eye on it.

hondaracer · October 28, 2009

i dont know for shure i just heard it was, but if it isnt i would like to upgrade to a 2500 or a 3500 transmision if it dosent involve body trimming. thanks for the advice, i haul a large camper for long trips. i didnt want to purchase a new vehicle so i have a 4 grand budget to add on payload.

66nova · October 28, 2009

i dont know for shure i just heard it was, but if it isnt i would like to upgrade to a 2500 or a 3500 transmision if it dosent involve body trimming. thanks for the advice, i haul a large camper for long trips. i didnt want to purchase a new vehicle so i have a 4 grand budget to add on payload.

If you have a 4L80E, you already have the 2500/3500 transmission. But, I highly doubt you have the 4L80E if you have the 5.3. You more than likely have the 4L60E. You could get the 4L80 in the Yukon if you got an a 3/4 ton, so I doubt there is much to the install. You will probably have to get a custom tune for the PCM and may have to have a different length driveshaft. But, don't quote me on that, it's purely a guess.

trigen7 · October 28, 2009

It would be odd to see a factory installed 4L80E on a 5.3L but stranger things have happened. Easy way to tell is to crawl underneath and count the bolts on the tranny pan. If the tranny pan is pretty much rectangular and has 16 bolts, it's a 4L60E. If it has 17 bolts and is not too square, then it is a 4L80E.

dlstewart01 · October 28, 2009

There is not a 4L80 behind a 5.3. in a half ton. Even the Denali had a 4L65E behind the 6 litre in a half ton.

gmtech4 · October 28, 2009

puttting in an 80 will require a few things and if you ask here ,you don't have an idea what you are in for ,

cooler lines

crossmember mod

driveshaft mod

complete electrical harness

computer

but hey ,go with it!!!

Stevens03 · October 28, 2009

Why not upgrade the internals of the 4L60e. Thats what basically the 4L70e is? Besides, doesnt the 4L60e have a lower first gear?

Nytemare · October 28, 2009

yup...the 4l60E has a much lower 1st gear

the 4L80E will require everything gmtech4 said...plus, if its anything like my truck you will need a 2" body lift.

If you want to tow with it, get a shift kit...something like a trans go Jr shift kit, and a tune for towing. That's your best bet if you are on a budget.

Oh and get yourself a trans cooler also, if you don't already have one. You obviously have the usual hookup to the rad, but if your truck came with a tow package, you may have an external cooler already.

Just upgrading the trans is not going to increase your tow-able load, but it will handle the load better. The biggest thing you can do for towing is decrease the temp created by the shifts. That's where the shift kit comes in, making shifts quicker reducing temps, as well as the tune. Than a big external cooler to decrease the heat further.

Another thing I just thought of is get yourself a deeper aluminum finned pan. it will hold more fluid, and the fins help dissipate heat as well. Trans-Go makes these pans, and they're only around 100 bucks.

Also, when towing...only tow in 3rd gear, or lower. Do not tow in 4th. The trans will shift between 4 and 3 on every little grade and again increase heat generated.

WilliamBos · October 28, 2009

Can a 4L60E be beefed up to equal a 4L80E?

gmtech4 · October 28, 2009

to read a code for the transmissions is as follows:

4-- 4 speeds

L--- Longitudinal(sp)

last 2 # ---- is a torque handing capibility # that hydromatic uses

all hydromatics use this formula,,a 3T40 is a little frt wh drive tranny (T) stands for transverse that was in my Beretta

just do as nytmare said ,thats it .

you'll be fine ,

gmtech4 · October 28, 2009

I double posted but I like the saying below,

just remember your diff is the fuse for the tranny ,lol

trigen7 · October 28, 2009

I double posted but I like the saying below,

just remember your diff is the fuse for the tranny ,lol

A very good point. A good upgrade to a nice posi-trac diff would be a good start. Maybe even a taller gear ratio too. Something that will put you in your powerband quicker so you are utilizing the power that the engine makes at the speed you need it.

Yes a 4L60E can be beefed up. There are plenty of aftermarket transmission places that sell beefed up transmissions and or kits to rebuild them. Even with a good transmission, the other posts above hit all of the good points. Tranny cooler, bigger deeper pan, shift kit, tune, if you don't have a "tow" button you can put one in, upgrading the rear end, etc.

For $4k, you should be able to come up with some nice upgrades.

Nytemare · October 29, 2009

A 4L60E can be beefed up to handle 700HP reliably. But you don't need anything near this to tow reliably. A stock trans with a few mods like I mentioned before will be fine. But yeah...the rear end is definitely the fuse.

Also what trigen7 meant to say is a shorter gear ratio...taller would mean that you put smaller number gears in.

best for towing is 4.10:1, but you would be fine with 3.73:1 if you stick with stock size tires.

hondaracer · November 1, 2009

I thank you all for the advise I realy needed some I am mechanically inclined but am lacking experiance with these particular vehicles. I would rather buy a 00-06 2500 suburban than try to make a 1500 what it's not. From reading these posts it seems that The time/money that was gunna be put in this suv is just not worth it.

Does anybody know a good price or what to look for in a 00-06 k2500 Suburban/YukonXL?- thanks