View Full Version : Just about to Swap Transmissions

01-07-12, 02:13 AM
New Transmission with a whole bunch of Valvoline Dexron VI. Check


Access to the bottom of the car. Check


More pictures tomorrow.

01-07-12, 04:44 AM
Good luck and be careful; will love to follow the swap (via pictures).

01-07-12, 01:09 PM
Wow this should be fun.

Good Luck & thanks for taking pictures.


How about a quick refresh on why you're doing this? I found your earlier post on it but it would be great to have the whole story in this thread.

01-07-12, 10:10 PM
The trans basically has no 4th gear. It would shift form third, try to get fourth, and then kick down to third and up to fifth. The cost to fix the trans runs real close to the cost for a whole new trans. So the whole trans must come out.

Almost have it out. There is one bolt, up at the top of the transmission that is giving me hell. Where it's located you have almost not room to get at it to remove it. Back to the battle. Might just be removal today, and installation tomorrow.

01-08-12, 12:14 PM
Top bolt, or two, on transmissions/bellhousings.

I've had only one vehicle on which this wasn't an absolute nightmare.

Nice to see it's still a problem...


01-08-12, 08:14 PM
I wonder what the cost is?

as you know I always do the valuation of cost to repair/what the car is worth fixed


01-09-12, 11:00 AM
The cost of the transmission was around $2000. The dealer I bought the car from provided a 90day 3000mile warranty, which covered up to $2000 worth of repairs. The cost for the dealer to install the trans was about another $1000, so I opted to do it myself.

mckellyb, those two bolts probably took 75% of the removal/installation effort. From reaching in the very small confined space, my arm is pretty bruised on the forearm. The trans is all back in now, I will be posting the additional pictures soon. With how difficult those top two bolts were, it makes me think the extra $1000 for the dealership to do it may have been worth it. :/

01-09-12, 06:41 PM
Nice job. Glad to see some members under their STS. No offence, but coming from a Chrysler 300M forum (my previous car), where we had a huge DIY thread and all the members did their own work, it's odd to come over to a forum where most members prefer to have dealers and mechanics do their work.

You know, this thread brings up a good point. The entire time I've been on this forum I haven't found a nice write up on tranny service. Im having alot of fun with my STS on the road, so I'm planning on doing the tranny service at 50k miles. Having heard countless dealership nightmare stories, I would love to do the service myself, but would love to know the details on how. I've read about dropping the tranny, but sounds like a huge hassle (lol, you would know right?). I've also read about just draining it, measuring the fluid, and then just hand-pumping the same amount into the hard-to-reach filler cap - the question is, what if some fluid has leaked out over the years and now your tranny is running on low fluid? The third option I read about was pumping the tranny fluid in through the cooler lines with the engine running. Sounds easy, but I haven't seen/heard of it done specifically on an STS. What are your thoughts, being a DIY guy? Also, what are the thoughts of anyone who's done/ done research on this service. Thanks

01-09-12, 10:58 PM
The transmission on these cars are quite sophisticated. They come sealed, from the factory with the fluid, and the correct amount for the cooler too. Which I didn't realize when I picked up all the transmission fluid. The proper way to check the fluid on this car, is to get it up in the air, and level, get the trans up to operating temperature, with the engine running, shift the trans through the gears, place it back in park, and then go under, remove the fill plug. Your level should be right at the bottom of the fill hole. While this sounds fine and dandy, on my car, due to where the exhaust is routed, getting to that fill hole is not at all easy. Also, one thing I noticed, on the trans I pulled out of the car, there was a drain plug on the bottom. The new trans has no drain plug. I can't imagine the turn it on , spew from the cooler lines, and refill is that difficult, I haven't looked into where the cooler lines go into the cooler. The risk of this is added contamination to the system.

Your car is also a 2005, so if you still have the original transmission fluid, and it has never been serviced, you will have a factory fill of Dexron III-H, which was discontinued in 2006 and has been superceded with Dexron VI. So becareful when you are looking to buy fluid, if it says "Suitable For Dexron III, it is not an officially licensed product, as no licenses exist anymore. It therefore isn't tested and may have implications of voiding warranty if used. You will want to use Dexron VI, which is backwards compatible with Dexron II and III

The trans swap is all done. It is running and driving, and now it does shift into fourth gear. I will say the swap is pretty straight forward. I would say probably 70% of the time to get it out/in was spent on the upper two bolts securing the trans to the engine. The biggest headache, was those bolts also secure a bracket used to zip tie the wiring harness to and support. On the bolt on the passengerside of my car, the harness was routed directly behind the bolt, so I struggled to get it all the way out. Then getting them in was also a pain.

I don't see a whole lot of DIY on here. With most newer cars thought, there are so many electronics, it can be somewhat overwhelming. My last car, a 1989 Oldsmobile 98, didn't have much electronics wise to go bad. It also shared a drive train with several other GM cars with it's 3800 V6 and 4T60 transmission. The engine and trans in my Caddi (and yours too) is just in Cadillac. They may have started using the trans in other models now. With that being said, it seems a Cadillac owner is generally a little older, a little more mature and affluent with the extra income to pay a shop to do the work. For the most part I enjoy the maintenance and repairs of the vehicles I choose to own.

I have a good amount of pics, I will get them up shortly. I have to get them off the camera.


01-10-12, 01:02 AM
how many miles were on the old trans and did ever have torque convertor problems..the so called chuggle...i have a o5 sts 4 awd fully optioned w n* and it took the dealer 2 years and a 1 year at of warranty to figure out the convertor is bad..the dealer is changing it now but im going to fight gm for them to good will it...they re charging me 3100 dollars to do the job...the shitty part about it is im a mechanic but work on trucks (bigriggs)and dont have a lift or the space to do it...if the weather was a bit warmer id do it outside,just cant afford to tie a bay up...vinny

01-10-12, 10:02 PM
Did you save your work-orders? If the dealer doesn't honor the claim with some polite pressure, just go to the Cadillac zone rep.