Cadillac Owners Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
Purchased a '10 3.0 model about 10 months ago now with about 90k on the clock. Been a maintenance nightmare ever since, and for about the past 3,000 miles (driven just over 8,000 since purchased) the transmission has been slipping, especially during the shift from third to fourth gear- I can feel and hear a sort of clunking noise. I don't drive particularly aggressively, and I don't think the fluid has ever been changed. Would changing the fluid possibly solve this problem? Also, in the case the transmission has to be rebuilt or replaced - I have found a cheap '11 transmission with 30k pulled out of a 3.0 base model as well, would this be compatible? Or would it be cheaper simply to rebuild my existing unit?
 

·
Registered
2011 CTS Coupe FE3, 2003 Thunderbird, Gone 2013 ATS, 02 Deville
Joined
·
1,381 Posts
the first thing is change the oil and filter and use the proper Trans oil. (now this is when the remarks will start) I suggest using a quart on Lucas Transmission Fix with the oil change.
 

·
Registered
08 CTS DI
Joined
·
2,268 Posts
If you end up considering replacing the transmission with one from another car, it should be possible to have the transmission computer removed from inside your old trans (because oddly enough that's where GM decided to put it) and installed in the replacement to reduce the expense by a few hundred dollars, unless the problem you are having is the result of the computer. I do agree with attempting a fluid and filter change as a start. You should also search out a good transmission shop and have them run a diagnostic, it's possible the transmission could be fine and in need of reprogramming.

the first thing is change the oil and filter and use the proper Trans oil. (now this is when the remarks will start) I suggest using a quart on Lucas Transmission Fix with the oil change.
Remarks are appropriate, as some of us have had experiences with additives and special non OE specified procedures that have caused more harm than good. Honestly there is no shortage of additives on the market that offer nothing but claims, without any proof. I caution against any additive for any fluid on the car that is not OE recommended, UNLESS, you know what that additive will do.

It's just a suggestion to be careful, not a swipe at your recommendation. I've had to rebuild a transmission, because someone thought it would be a good idea to flush it, (Jiffy Lube yrs ago) when there was nothing wrong with it before hand. So yes I'm a bit over protective here.

I'm wordy I know, and I'm trying to change that, despite feeling closer to accepting. Thanks for that Uniden DC115 iWitness windshield cam recommendation, I bought three of those and they do work well.
 

·
Registered
'10 CTS4 3.6L Wagon prem; '06 STS 3.6L base; '98 Seville STS
Joined
·
2,356 Posts
Purchased a '10 3.0 model about 10 months ago now with about 90k on the clock. Been a maintenance nightmare ever since, and for about the past 3,000 miles (driven just over 8,000 since purchased) the transmission has been slipping, especially during the shift from third to fourth gear- I can feel and hear a sort of clunking noise. I don't drive particularly aggressively, and I don't think the fluid has ever been changed. Would changing the fluid possibly solve this problem? Also, in the case the transmission has to be rebuilt or replaced - I have found a cheap '11 transmission with 30k pulled out of a 3.0 base model as well, would this be compatible? Or would it be cheaper simply to rebuild my existing unit?
I'm guessing this is AWD? Also a transmission from a coupe will not work on the sedan/wagon, same with AWD and RWD. In any case, I rebuilt mine a couple years ago, had to do it because of the damage caused by the input/output shaft. Definitely cheaper but make sure a shop specialized in transmission work are the ones doing it

Sent from my SM-N920T using Tapatalk
 

·
Registered
08 CTS DI
Joined
·
2,268 Posts
Also a transmission from a coupe will not work on the sedan/wagon, same with AWD and RWD
Is that because there is a physical difference, or because GM has switched between a 6L50 and 6L45, or the valve body is different between them? I'm curious to know, as a shop owner that built a couple of trannys for me recently said some sad things about the 6L50, but stated the same transmission provided the cases are the same, can be swapped between different cars, without programming as long as the OE computer was installed into the donor trans. I recall a thread on the Camaro forum discussing the subject of some thinking they had a 6L50 and discovering instead they have a 6L45 depending on the year.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #6
I'm guessing this is AWD? Also a transmission from a coupe will not work on the sedan/wagon, same with AWD and RWD. In any case, I rebuilt mine a couple years ago, had to do it because of the damage caused by the input/output shaft. Definitely cheaper but make sure a shop specialized in transmission work are the ones doing it

Sent from my SM-N920T using Tapatalk
It is RWD.
 

·
Registered
'10 CTS4 3.6L Wagon prem; '06 STS 3.6L base; '98 Seville STS
Joined
·
2,356 Posts
Is that because there is a physical difference, or because GM has switched between a 6L50 and 6L45, or the valve body is different between them? I'm curious to know, as a shop owner that built a couple of trannys for me recently said some sad things about the 6L50, but stated the same transmission provided the cases are the same, can be swapped between different cars, without programming as long as the OE computer was installed into the donor trans. I recall a thread on the Camaro forum discussing the subject of some thinking they had a 6L50 and discovering instead they have a 6L45 depending on the year.
Physical difference, I bought an AWD transmission only to find out it came from a coupe (11), found out the hard way when they lowered mine and it looked different. Was the change made on that model year?

Sent from my SM-N920T using Tapatalk
 

·
Registered
08 CTS DI
Joined
·
2,268 Posts
Physical difference, I bought an AWD transmission only to find out it came from a coupe (11), found out the hard way when they lowered mine and it looked different. Was the change made on that model year?

Sent from my SM-N920T using Tapatalk
I'm not sure but it looks that way. The Camaro 6L50 for 2010 was for that year only and there is also a 2010 cutoff for the CTS transmission valve body, so given your description of a physical difference, that appears to be the case. That, or in case of the CTS, the 6L45 was used on the 3.0L and that's what you received.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #9
I'll go ahead and change the fluid and filter and see what happens.What are the benefits (or otherwise) of using the additives?
 

·
Registered
08 CTS 6.0L/6L80 conversion
Joined
·
241 Posts
Not sure where your at but I have a perfectly good shifting transmission I pulled out of my 2008 RWD 3.6L
 

·
Registered
2011 CTS Coupe FE3, 2003 Thunderbird, Gone 2013 ATS, 02 Deville
Joined
·
1,381 Posts
I'll go ahead and change the fluid and filter and see what happens.What are the benefits (or otherwise) of using the additives?
I have had good results with actual transmissions that had harsh or slipping when shifting and have used the Lucas to fix it. But I have never used it to fix noisy transmissions.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #13
I have had good results with actual transmissions that had harsh or slipping when shifting and have used the Lucas to fix it. But I have never used it to fix noisy transmissions.
yeah that sounds about right then, I'll give that a try as well.

Not sure where your at but I have a perfectly good shifting transmission I pulled out of my 2008 RWD 3.6L
I'm in central fl
 
1 - 13 of 13 Posts
Top