Put a new transmission in my 2004 Yukon…

[WickedGoat]

The transmission in my 04 Yukon finally crapped the bed back in February. Wife was driving it on the Interstate when it started revving to 5000 RPMS and wouldn’t get passed 50 MPH. She called me and told me what was happening and I told her to turn around and try to get back in the driveway, which she did.

I tried to go around the block with it that following weekend and that was a no go. Sounded like the pump was screaming and the fluid was burned and nasty. It had been slipping when shifting into 2nd gear for a while and it finally said no more. I bought my wife an Acadia back in 2019 when the Yukon trans started acting up so we got extended borrowed time on it.

I called a few shops in my area to get some quotes. $3500-ish was the ball park with a low of $2800 and the Chevy dealer being over $4000. Beyond the pricing, it is hard to find a good shop in my area that you can trust do the job right. The dealership was just too expensive for my 200k miles Yukon.

I then started to contemplate doing it myself and looked online for shipped to my door prices. Enter Summit Racing… They have an exact fit new transmission for our trucks that will support 450 HP and is advertised as correcting all of the factory defects that the factory ones were born with. The case and bell housing are stripped and painted, the guts are brand new, and they throw in a polished finned trans pan with a drain plug, all for the measly price of $1749 shipped to my house on a FedEx lift gate. I was sold. The only issue I had was the back order for the trans was excruciatingly long. I ordered it in February and got it in mid May. I ordered a converter from a reman shop in KC. I ordered a couple of parts from my local Chevy dealer and I ordered all the rest from Rock Auto.

I came in at approximately $2800 with all the parts I replaced and my labor. I had no help and spread it out over 5-6 days working here and there. The truck runs great and that transmission from Summit, so far, is worth every penny. Got about 175 miles on it so far and it has been great. I replaced the radiator, factory original, the trans lines, and a bunch of other stuff. Attached is my parts list with vendors, part numbers and prices.

 

[rockola1971]

Reason why your wife couldnt get over 50mph and was revving to 5000rpm AND the same reason it had been slipping going in to 2nd....... 2-4 band was slipping on the drum. The band is only used on 2nd and 4th(OD). Likely band just worn out from 200K on the tranny. It was its time. (Plays TAPS).

 

[swathdiver]

You did good man!

 

[WickedGoat]

I did the radiator and the trans lines because there was no guarantee that flushing would get all of the old fluid out. The radiator was also the original one so that was just a matter of time. I replaced the four hoses for the same reason and because I did the upper and lower rad hoses when I did the water pump and thermostat a couple of years ago.

The torque converter I used was a suggested part doing a search on this forum. I didn’t like my choices at Summit Racing because I just wanted a stock stall OE ride. The GM replacement was on indefinite back order. The trans mount is a no brainer. The starter got replaced because a stud on the solenoid snapped when I went to loosen a nut to remove the wiring and because it was oil soaked on the inside from the rear main seal leaking so bad.

The rear main was worse than I thought. A few months ago I replaced a lot of gaskets because of leaks and the Dorman rear main kit was one that I bought. I’m glad I didn’t do the rear main 8 months ago and then have to pull it all apart again for the transmission. Definitely do the rear main seal if you are DIY-ing the transmission for any reason.

Even though I dropped $2800 on this, the amount of work that got done could have easily hit $6k at a shop with today’s pricing shenanigans. I’d like to keep the truck for a little while longer as a back up car so this was worth it to me.

The Harbor Freight trans jack I bought in 2020 to do the slave cylinder on my GTO paid dividends on this job. I was also really surprised at how well things came apart with 200k miles on it. Besides the stud on the starter, the only other bolts that broke were the converter pipe to muffler pipe bolts. The heater core to hose connection adapters also broke on me because I leaned a little too hard trying to keep my balance working back there. They were original pieces as well. Overall, this was a time consuming but rather simple job to do.

 

[WickedGoat]

Two more things worth mentioning about this replacement… I went to AutoZone and bought a Felpro transfer case to transmission gasket and it didn’t fit. It was off by half a stud on two of the studs no matter how I positioned it. Took it back and went to O’Reillys and bought their Pioneer gasket. Same thing, it would not line up properly. I am thinking WTF at this point. That is why I went with the dealership parts gasket and it was perfect.

The original shifter cable had been broken for some time where it slides into the bracket on the trans and locks into place. After determining it was time for a new one, a quick Google search led me back to the dealer for the part. The dealer price is right on with the parts stores and we know the dealer part will fit and work right.

I’ve posted some long replies but I am trying to put some useful info up if anyone else comes along wanting to know about replacing their transmission themselves. Before I decided to do this I read a few threads on here and watched some YT videos on it and the rear main seal replacement. Hopefully this helps someone in the future.

 

[Joseph Garcia]

Thank you for posting this detailed report on your replacement project.

 

[WickedGoat]

An update after almost 2000 miles of driving…

The transmission has been damn near perfect. The truck has driven great on all of the trips we have taken over the summer. There were two issues with it that I just finished addressing this morning and wanted to mention it so that it can be checked and addressed before installation, should another member buy one.

I came home from work one night last week and saw a big wet spot under the truck. Checked it with my fingers and it was bright red transmission fluid. Crawled under it and found it leaking from the pan bolts. I tightened them up and found two that wouldn’t tighten up so I removed them and determined the hole threads were stripped. I also didn’t like the cork gasket that was used on the pan so I picked up a Felpro rubber/fiber gasket. I ordered a helicoil repair kit to fix the bolt holes.

I just finished this a little bit ago. I found a 3rd hole that didn’t look good so I repaired that one as well. I used helicoils because this was a low torque, low stress application so time serts would have been overkill. Buttoned it all back up and filled it back up with fluid and let it run for 20 mins in the driveway while I cleaned up, and then I took it for a 15 mile ride and it is bone dry. All the bolts tightened down properly and the Felpro gasket is much better than the cork one.

So, if anyone orders one of these transmissions from Summit, do yourself a favor and replace the cork pan gasket with a rubber one and check those thread bolts. It’s a minor inconvenience for a DIY person but I could see being upset if you had to take it to a shop to fix it on top of the transmission replacement costs. I’m still happy with the transmission despite these two minor issues.

 

[SuperOldSchool]

Really nice job! Love seeing folks take big projects on with success!

 

[WickedGoat]

Really nice job! Love seeing folks take big projects on with success!

It wasn’t bad at all, just a little time consuming given my 55-60 hour a week work schedule. The shops around me wanted $3500 to rebuild my trans and that was motivation enough to take this on and get it done. I’d do it again as a side job with no issue.

 

[S33k3r]

An update after almost 2000 miles of driving…

The transmission has been damn near perfect. The truck has driven great on all of the trips we have taken over the summer. There were two issues with it that I just finished addressing this morning and wanted to mention it so that it can be checked and addressed before installation, should another member buy one.

I came home from work one night last week and saw a big wet spot under the truck. Checked it with my fingers and it was bright red transmission fluid. Crawled under it and found it leaking from the pan bolts. I tightened them up and found two that wouldn’t tighten up so I removed them and determined the hole threads were stripped. I also didn’t like the cork gasket that was used on the pan so I picked up a Felpro rubber/fiber gasket. I ordered a helicoil repair kit to fix the bolt holes.

I just finished this a little bit ago. I found a 3rd hole that didn’t look good so I repaired that one as well. I used helicoils because this was a low torque, low stress application so time serts would have been overkill. Buttoned it all back up and filled it back up with fluid and let it run for 20 mins in the driveway while I cleaned up, and then I took it for a 15 mile ride and it is bone dry. All the bolts tightened down properly and the Felpro gasket is much better than the cork one.

So, if anyone orders one of these transmissions from Summit, do yourself a favor and replace the cork pan gasket with a rubber one and check those thread bolts. It’s a minor inconvenience for a DIY person but I could see being upset if you had to take it to a shop to fix it on top of the transmission replacement costs. I’m still happy with the transmission despite these two minor issues.

I live near a Summit, and their warranties are good. Sometimes their vendors suck, but Summit's service is pretty good. Meaning you could have returned what you had for a replacement -- if you were willing to wait.

 

[Mudsport96]

What brand radiator did you get? I may have missed it in my reading.
If it is a mediocre off brand, it may not have the restriction in the surge tank fitting. Can be hard to see in there when it is in the truck. So, if you have issues this winter with it not warming up you know why. I remedied this in my Silverado by putting a primerless .45 acp casing in the hose to the tank and pinching it in place with a hose clamp lol.

 

[SuperOldSchool]

Redneck engineering at its best!

‘Merica

 

[WickedGoat]

I live near a Summit, and their warranties are good. Sometimes their vendors suck, but Summit's service is pretty good. Meaning you could have returned what you had for a replacement -- if you were willing to wait.

You are right about their warranty being good. Also, their customer service is also top notch.

I ended up experiencing another leak and this time, Summit sent me a replacement GM transmission oil pan and gasket to replace the pan that the trans came with. The GM pan has a ridge that runs the perimeter of the pan flange and will create a better seal when tightened down. The pan that came with this transmission did not have the ridge and after speaking with Summit Tech and customer service, they told me to pick out a new pan and they would ship it to me for free. I chose the stock GM pan and it was at my door in 3 days. I went to AutoZone and bought 16 new flanged bolts and swapped the pans the following weekend.

I purposely waited to make sure there were no leaks before I updated this thread. It has been two weeks now and the truck has been driven like 500 miles and there are no more leaks. It shifts and drives great. So now I will further advise anyone that buys this transmission to ditch the fancy chrome one that comes with it and use your stock pan or the Dorman pan, and your stock pan bolts. I did have to buy a replacement trans filter since the GM pan is the shallow side deep pan where the chrome pan was completely deep. There are two different filters for these pans. I just ordered and received two cases of Delco Dexron VI trans fluid because my Impala and Acadia are due for drain and fills again so I ordered another case just to flush the Yukon. I’ll give it another couple thousand miles and flush the old stuff out.

I do believe Summit will stand behind the trans if it comes down to it but I think I am good to go now. It sounds like I have been through an ordeal with this but it hasn’t been that bad. The truck isn’t a daily driver so that was a plus. This also was another reminder that sometimes the stock parts are a better choice. All I know is that it is nice having Old Faithful up and running good again! It needs a couple more things done but nothing pressing.

 

[WickedGoat]

What brand radiator did you get? I may have missed it in my reading.
If it is a mediocre off brand, it may not have the restriction in the surge tank fitting. Can be hard to see in there when it is in the truck. So, if you have issues this winter with it not warming up you know why. I remedied this in my Silverado by putting a primerless .45 acp casing in the hose to the tank and pinching it in place with a hose clamp lol.

It was the OSC, part number OS 2921 from Rock Auto. I posted a pic of a part number spreadsheet I made up to get a final tab on this project. I’ve had no issues with the radiator or cooling system, especially with these hot days we have been having. I will keep an eye on it this winter though.

 

[WickedGoat]

Final update to this project… the transmission has not leaked since the pan swap and it has continued to run fantastic. I bought a case of AC Delco Dexron 6 to do a fluid change on it within the next 5000 miles but other than that, I would definitely buy another Summit transmission and recommend it for a DIYer looking to save money. I don’t know how a random repair shop would feel about installing this transmission but it is definitely worth it to ask if they will if you can’t DIY.

So to summarize, if you go with this transmission, remove the supplied pan and gasket and get a new GM gasket and retain your old trans pan and bolts. If your old stock pan didn’t have a drain plug, you can add one yourself or just go buy the Dorman pan that has the plug but also retains the ridge around the pan lip that helps seal it up better.

 

[Henryjs453]

The transmission in my 04 Yukon finally crapped the bed back in February. Wife was driving it on the Interstate when it started revving to 5000 RPMS and wouldn’t get passed 50 MPH. She called me and told me what was happening and I told her to turn around and try to get back in the driveway, which she did.

I tried to go around the block with it that following weekend and that was a no go. Sounded like the pump was screaming and the fluid was burned and nasty. It had been slipping when shifting into 2nd gear for a while and it finally said no more. I bought my wife an Acadia back in 2019 when the Yukon trans started acting up so we got extended borrowed time on it.

I called a few shops in my area to get some quotes. $3500-ish was the ball park with a low of $2800 and the Chevy dealer being over $4000. Beyond the pricing, it is hard to find a good shop in my area that you can trust do the job right. The dealership was just too expensive for my 200k miles Yukon.

I then started to contemplate doing it myself and looked online for shipped to my door prices. Enter Summit Racing… They have an exact fit new transmission for our trucks that will support 450 HP and is advertised as correcting all of the factory defects that the factory ones were born with. The case and bell housing are stripped and painted, the guts are brand new, and they throw in a polished finned trans pan with a drain plug, all for the measly price of $1749 shipped to my house on a FedEx lift gate. I was sold. The only issue I had was the back order for the trans was excruciatingly long. I ordered it in February and got it in mid May. I ordered a converter from a reman shop in KC. I ordered a couple of parts from my local Chevy dealer and I ordered all the rest from Rock Auto.

I came in at approximately $2800 with all the parts I replaced and my labor. I had no help and spread it out over 5-6 days working here and there. The truck runs great and that transmission from Summit, so far, is worth every penny. Got about 175 miles on it so far and it has been great. I replaced the radiator, factory original, the trans lines, and a bunch of other stuff. Attached is my parts list with vendors, part numbers and prices.


View attachment 372876

When you replaced the trans did you have to do any scanning for trans codes or just do the swap and start driving? Was it a 4x4 ?

 

[WickedGoat]

When you replaced the trans did you have to do any scanning for trans codes or just do the swap and start driving? Was it a 4x4 ?

I just did the swap and started driving, and yes, AWD.

 

[Henryjs453]

I just did the swap and started driving, and yes, AWD.

Thanks. I am looking at replacing mine @200k miles and have found the same pricing as you. I was wondering about the summit transmissions and feel better hearing about your experience.

 

[WickedGoat]

Thanks. I am looking at replacing mine @200k miles and have found the same pricing as you. I was wondering about the summit transmissions and feel better hearing about your experience.

Just save your old trans pan and bolts to swap over to the new transmission, unless your stock pan doesn’t have a drain plug and you want one… Then I would buy the Dorman replacement pan. You will most likely need a replacement filter to accommodate the stock or Dorman pan. I’d buy the GM gasket also. You can sell the fancy pan and bolts and recoup some cash back.

The R&R is straight forward. At your mileage, I’d do the rear main seal while you are that close to it. Mine was leaking and I had the parts on hand prior to the transmission crapping on me.