New transmission for upgraded 5.3L engine?

[Bill Barnes]

I have a 2005 Yukon XL with the 5.3 Flex engine. It has 214K on it, and runs great, but I'd like a bit more power, so I'm considering a new crate engine in the next year or so. I am also sure that the current 4L60E won't handle the 400 or so HP I am looking for. I would welcome any advice from the forum members on whether to upgrade to a 6.0 or 6.2 engine, and what I would need for a tune or new ECU. I also need advice on what transmission to upgrade to, and what to do about the controller for that. Thanks in advance! I have enjoyed being a supporting member for tha past 7 or 8 years, and I am sure that some of you have experience with what I want to do.

 

[S33k3r]

What's your budget? What are your design goals, in addition to 400 hp? Are you looking for 400 hp at the wheels? You're a little open-ended at this point, so we'd need more specific information to help. For example, if you had a big budget, you could upgrade to a 6 spd transmission.

 

[Mudsport96]

X2. 400 crank isnt too terrible to attain and really doesnt require a crate engine just some elbow grease basically ANY aftermarket cam will get you there...400 wheel is a fair bit of work.
Or just drop in a stock 6.0

 

[Tonyrodz]

My 03 Tahoe originally came with a 4.8 and the 4l60 trans. Bought it with 212k on it. Swapped out to a cammed and tuned 6.0. The trans was shifting great, I had no issues with it. Around the 1st week after the swap I ran into an Acura that was messing with me. Of course I had to make a believer out of him lol. I probably went a little over 100 mph, beat him--slowed down some to get to normal speeds. I stepped on the gas to accelerate normally and I had nothing. I don't know what you're driving style is but imo your trans will eventually give up the ghost. Had my rebuilt a little better, hardened clutches, shift kit, vette servo, 3000 Circle D convertor and bigger capacity trans cooler. I haven't had an issue with it since. Biggest thing that kills these transmissions is heat. Imo your 4l60e will be just fine, you'll just need to be proactive and beef it up before you blow it with the new power. You can upgrade your existing 5.3, or go bigger to a 6.0, and you could even stroke it for bigger cubes.
You can reuse your existing ecu, just have it reflashed for your new mods but a competent tuner--someone who knows what they're doing.
I'm sure someone more knowledgeable will chime in shortly.

 

[rockola1971]

Pretty much what tony said. Your well worn in 214k tranny isnt going to hold up to a 400hp+ engine for very long. The good news is that it can be rebuilt at a reasonable cost in replacement parts to hold up to it. All valve body updates need performed, beast hardened sunshell or equivalent, zpack clutches, Hi energy clutch kit, corvette servo, kevlar 2-4 band or equivalent, trans cooler if not already equipped and go big, 5 pinion planetary, matched convertor and a guy that knows what he is doing while in your trans.

While you have the Tcase down you might as well get it rebuilt also. Guarantee if it has never been touched that you have the pump rub hole or the hole has almost worn through the rear case of the TCASE. You may need a new rear case half which arent too expensive. Dont be afraid to do the Tcase yourself. The only real special tools needed are bearing driver set, long reach internal/external snapring pliars and torx bit set. Plenty of youtube vids that show step by step. Save yourself some money on labor costs. You will need a bearing and seal set, new chain, clutch set if you have auto 4wd and rarely any other hard parts but inspect yours and replace if necessary. Dont forget to get a pump rub spacer to fix that problem too. They are around $20 or so.
You dont want the original chain to stretch enough that it whacks the inside of the case and rips a big hole in the Tcase. If you do....make sure your wife is driving it when it happens like I did!

 

[S33k3r]

Pretty much what tony said. Your well worn in 214k tranny isnt going to hold up to a 400hp+ engine for very long. The good news is that it can be rebuilt at a reasonable cost in replacement parts to hold up to it. All valve body updates need performed, beast hardened sunshell or equivalent, zpack clutches, Hi energy clutch kit, corvette servo, kevlar 2-4 band or equivalent, trans cooler if not already equipped and go big, 5 pinion planetary, matched convertor and a guy that knows what he is doing while in your trans.

While you have the Tcase down you might as well get it rebuilt also. Guarantee if it has never been touched that you have the pump rub hole or the hole has almost worn through the rear case of the TCASE. You may need a new rear case half which arent too expensive. Dont be afraid to do the Tcase yourself. The only real special tools needed are bearing driver set, long reach internal/external snapring pliars and torx bit set. Plenty of youtube vids that show step by step. Save yourself some money on labor costs. You will need a bearing and seal set, new chain, clutch set if you have auto 4wd and rarely any other hard parts but inspect yours and replace if necessary. Dont forget to get a pump rub spacer to fix that problem too. They are around $20 or so.
You dont want the original chain to stretch enough that it whacks the inside of the case and rips a big hole in the Tcase. If you do....make sure your wife is driving it when it happens like I did!

Oh! That is why you were asking about insurance in that other thread...

 

[rockola1971]

Oh! That is why you were asking about insurance in that other thread...

Not sure what you are talking about ????

 

[swathdiver]

I have a 2005 Yukon XL with the 5.3 Flex engine. It has 214K on it, and runs great, but I'd like a bit more power, so I'm considering a new crate engine in the next year or so. I am also sure that the current 4L60E won't handle the 400 or so HP I am looking for. I would welcome any advice from the forum members on whether to upgrade to a 6.0 or 6.2 engine, and what I would need for a tune or new ECU. I also need advice on what transmission to upgrade to, and what to do about the controller for that. Thanks in advance! I have enjoyed being a supporting member for tha past 7 or 8 years, and I am sure that some of you have experience with what I want to do.

You can upgrade your 4L60 to 4L65 standards with hardened and special parts that will easily handle 500 horses or so.

 

[rockola1971]

You can upgrade your 4L60 to 4L65 standards with hardened and special parts that will easily handle 500 horses or so.

The key differences between a 4L60E and 4L65E are: (1) Hardened 300mm input shaft (2) 5 pinion Planetary (3)Hardened sunshell
Its not very common to have problems with the input shaft but the 4 pinion planetary and non hardened sunshell of the 4L60E create very common problems of failure behind a modified engine and even stock engines.
The 4L60E has a 298mm input shaft and torque converter specific to that. The 4L65E has a 300mm input shaft and torque converter specific to that input shaft. The torque converters are NOT interchangeable without a input shaft swap. You can stick a 5 pinion planetary (4L65E) directly into a 4L60E tranny during rebuild. No mods at all necessary for that swap. Simple drop in. The 5 pinion spreads the load out across 5 pinions instead of 4. The beast sunshell or equivalent is a direct swap in no mods required and is a hardened part. The oem sunshell is prone to its splines stripping out or breaks at the welded area.
If a 4L65E tranny is installed into a 4L60E application then a PCM reprogram will be needed.
The 4L60E and 4L65E are the same external dimensions because the 4L65E is just a beefed up 4L60E from the GM engineers. Same gear ratios.
RPO code for 4L60E is M30 and the 4L65E is M32. GM started internal changes/upgrades to the 4L60E in 2001.
To make matters even more confusing it is possible to have a factory "M32 badged" 4L60E that is factory upgraded but has a M30 RPO code but it is not a true 4L65E but instead is a in between.
"If you are looking at the transmission itself, the M32 number should be listed on the transmission itself. M32 is also a high performance version of the 4L60E, depending on the year. It’s really confusing."

4L65E Transmission | Drivetrain Resource

4L65E Identification, RPO Codes, Specs, and differences between it and the 4L60E can be found on this page.

www.700r4transmissionhq.com

 

[Tonyrodz]

The key differences between a 4L60E and 4L65E are: (1) Hardened 300mm input shaft (2) 5 pinion Planetary (3)Hardened sunshell
Its not very common to have problems with the input shaft but the 4 pinion planetary and non hardened sunshell of the 4L60E create very common problems of failure behind a modified engine and even stock engines.
The 4L60E has a 298mm input shaft and torque converter specific to that. The 4L65E has a 300mm input shaft and torque converter specific to that input shaft. The torque converters are NOT interchangeable without a input shaft swap. You can stick a 5 pinion planetary (4L65E) directly into a 4L60E tranny during rebuild. No mods at all necessary for that swap. Simple drop in. The 5 pinion spreads the load out across 5 pinions instead of 4. The beast sunshell or equivalent is a direct swap in no mods required and is a hardened part. The oem sunshell is prone to its splines stripping out or breaks at the welded area.
If a 4L65E tranny is installed into a 4L60E application then a PCM reprogram will be needed.
The 4L60E and 4L65E are the same external dimensions because the 4L65E is just a beefed up 4L60E from the GM engineers. Same gear ratios.
RPO code for 4L60E is M30 and the 4L65E is M32. GM started internal changes/upgrades to the 4L60E in 2001.
To make matters even more confusing it is possible to have a factory "M32 badged" 4L60E that is factory upgraded but has a M30 RPO code but it is not a true 4L65E but instead is a in between.
"If you are looking at the transmission itself, the M32 number should be listed on the transmission itself. M32 is also a high performance version of the 4L60E, depending on the year. It’s really confusing."

4L65E Transmission | Drivetrain Resource

4L65E Identification, RPO Codes, Specs, and differences between it and the 4L60E can be found on this page.

www.700r4transmissionhq.com

Why would a reflash of the pcm be needed if beefing up internally a 4l60e to a 4l65e? Would that be if only going to a 5 planetary from the stock 4 planetary? I'm confused on this.