2003 Yuk Transmission Fluid Change

[mindensgb]

I have a 2003 Yuk with 138,000 miles and I'm getting ready to change the transmission fluid and filter. It currently has Dex III in the case and I'm told that there is a service bulletin that says to now use Dex VI. Is it OK to top off the trans with Dex VI (mix Dex VI and Dex III) when I button it up? Also, should I change the boost valve and how difficult is it to change?

 

[Sasquatch]

I`m not sure about mixing the two but i don`t think it would hurt.

One of the members here did this writeup on how to flush all the fluid out of your transmission http://www.truckmodcentral.com/forums/f63/how-flush-your-transmission-gmt800-gm-truck-4699/

Many here have done it this way including myself and it works great and is very easy. I switched to dex VI and have had no problems after about 12k.

The worst part of dropping the pan is removing the shift linkage bracket. They`re torx bolts and don`t come out easily. I tried to remove mine with no luck so i just bent the bracket enough to get the pan down. I never bent it back because it didn`t affect it`s operation.

I have no clue on the valve so hopefully someone else knows.

 

[FrankU]

One of the members here did this writeup on how to flush all the fluid out of your transmission http://www.truckmodcentral.com/forums/f63/how-flush-your-transmission-gmt800-gm-truck-4699/
.

Thanks for posting that link.

 

[z0lt3c]

I wouldn't touch the transmission at that mileage and age. Drive the thing until it dies and then just replace it. A rebuilt transmission can be found and installed for under $800 in my area of the country. At that price, it doesn't make alot of sense to spend $100-$200 on fluids and parts. Just my $.02 cents. If you do decided to flush it, I would suggest replacing the drain plug, I've seen alt of stripped drain plugs for some reason.

 

[Sasquatch]

If you`re the original owner or have the service records from the previous owner and it has had a fluid and filter change before i wouldn`t hesitate to do it again but,

If it has never had one before and the fluid is brown and smells burnt i would leave it alone.

 

[Jewel or Jalopy]

I did a flush on ours last year at about the same mileage. It seemed to slip a bit on shifts before that. Much improved afterword.

I would definitely do it if the fluid smells burnt. Nothing to lose but a case of fluid. I found dex 3 on sale at Costco and used about 14 qts.

I wouldn't mix fluids.

 

[new2yukon]

I have done a ton of reading on car sites and trans fluid changes. The general consensus is that if it has never been changed and the mileage is high you should change only a small amount at a time and then give the trans time to adjust. Go easy on it this way until all of it is changed. Be sure to change the filter. A lot of buildup could be in there and all new fluid at one time could be too much of a cleaner for the system to deal with at one time.

No matter your choice, I feel a gradual process of new fluid is much better than letting it go and waiting out the inevitable.

 

[z0lt3c]

A full flush is right around 12 quarts and a decent fluid will cost about $10/qt. The filter and gasket runs around $25 and if you want to replace the pan/plug, add another $43. That gets you pretty close to $200 for the complete service package. Since a brand new, rebuilt, 4L60E transmission (with fluid) is only $600 -- you are spending 1/3rd the price of the unit to simply maintain it. This service may make sense when you are talking about a more expensive transmission, but I just don't see the value of spending the money to service what would be better to just replace, whenever that time may come (since it hasn't happened yet in 140K miles), consider the rebuilt unit has many upgrades. To those who believe something magical happened to their transmission when they flushed the fluid, 9/10 times this doesn't happen.

 

[mattluttrell]

Just spent around $60 to swap out my fluid in my 145K Escalade. I'm glad I did it. It really only too about 20 minutes. I used a brass fitting and a clear 1/2" hose from my fish tank. The fluid coming out was black. I operated the bucket pump while my wife sat in the driver's seat. I have yet to have a GM transmission go bad by keeping up with the maintenance as recommended in the manual. I'm not going to start now.

This is a cheap and easy maintenance if you have a bucket pump and brass fitting. I hooked up to the top of the radiator so no old fluid was left in it.

 

[wreedps]

I have done a ton of reading on car sites and trans fluid changes. The general consensus is that if it has never been changed and the mileage is high you should change only a small amount at a time and then give the trans time to adjust. Go easy on it this way until all of it is changed. Be sure to change the filter. A lot of buildup could be in there and all new fluid at one time could be too much of a cleaner for the system to deal with at one time.

No matter your choice, I feel a gradual process of new fluid is much better than letting it go and waiting out the inevitable.

x2 what he said, take it slow in changing the fluid out on a high mileage trans.