5.7 swap to 6.5 diesel

[K1500 6.5]

Have a k1500 with a 4l60 trans and I have a 6.5 ready to go in it but the flywheel won’t mount up to the trans any suggestions

 

[ak diesel driver]

don't use the 4l60 it won't hold up to the 6.5 anyway

 

[Wreckinball67]

I believe that the torque converters are different plus, I'm with AK on this one. The smaller transmission won't hold up. Suggestion: since you already have a 6.5 ready to go, why not just find another truck (they're out there) that's already a diesel that has a bad motor? That way you can have two trucks

 

[THEFERMANATOR]

If you're dead set on it, you can buy a flexplate from a 95 c1500 that had a naturally aspirated 6.5l in it. GM only put 4l60e's behind the non turbo 6.5's for 2 years, and they were NIGHTMARES!

 

[LessThanClaypool]

Unless the 4L60e is built, don't put that diesel on it. The 4l60e had problems holding onto a TBI 350, so the diesel is out of question for sure. 4L80 or TH400, I'd personally go for a manual trans.

 

[Husker6.5]

Even IF that 4L60E is "built", don't use it! The 700R4/4L60E just was never designed to hold the low rpm torque a 6.5TD produces. Yes, there are Racing-built 4L60E's that can go behind a 600+HP gasser, but that torque is up above 4000 rpm, not down at 1800 rpm, and you just can't stuff enough steels and frictions into one to hold through 1-2-3, let alone make the OD section and TCC beefy enough to hold that torque. Hell, the 700R4 in my van couldn't hold the 310 HP 327 SBC in front of it, it lost its OD section and TCC. For the cost of building a still not strong enough 4L60E, you could buy two or maybe three remanufactured stock 4L80/85E's that can handle a 6.5 in front of them.

 

[smokymtn65]

700r4 cant stand up behind stock 6.2 N/A
I know..

 

[LessThanClaypool]

A 700r4 puked its guts with a 305 smallblock on it. Maybe look for a manual trans setup for it?

 

[Big T]

Friend said that the 4L60E would barely last 100K miles in his 1500 Suburbans. He was and still is in shock over how long the 4L80E last in my K2500 Suburban.

 

[Will L.]

I think putting it in perspective if the key. The 4l60 isn’t junk, it is really good but it is 60 meaning 6,000 pound maximum capacity.
4l80 is meant for 8,000 max capacity, but the 4l80 is just so amazingly designed that they can be upgraded to handle weights way into high teens and still last 100,000 miles.
It took allison- who made their money making auto transmissions for semi trucks, trash trucks, etc. to take their insanely well designed transmissions and shrink it down to fit in a pickup to finally beat the 4l80 platform.

But as to allison really beating it, there are some points the 4l80 still wins. In fleets we learned just leave it alone, dont even do filter changes in trucks and suburbans that don’t tow heavy and you will still get 250,000 miles before the first hiccup, and 200,000 if it did tow heavy. Don’t do that to the ally- shes gonna have problems at 150,000ish it you don't do basic filter changes.

Modern transmissions in many cars extend their life by being completely sealed. By not venting and not having a dipstick it keeps out dirt and most importantly moisture. I know a big part of that is the difference in oil, but I wonder if that technique would make the 4l80 last even longer. Imagine a pickup that tows heavy getting 300,000+ miles and never needing filter or oil.

 

[Big T]

I think putting it in perspective if the key. The 4l60 isn’t junk, it is really good but it is 60 meaning 6,000 pound maximum capacity.
4l80 is meant for 8,000 max capacity, but the 4l80 is just so amazingly designed that they can be upgraded to handle weights way into high teens and still last 100,000 miles.
It took allison- who made their money making auto transmissions for semi trucks, trash trucks, etc. to take their insanely well designed transmissions and shrink it down to fit in a pickup to finally beat the 4l80 platform.

But as to allison really beating it, there are some points the 4l80 still wins. In fleets we learned just leave it alone, dont even do filter changes in trucks and suburbans that don’t tow heavy and you will still get 250,000 miles before the first hiccup, and 200,000 if it did tow heavy. Don’t do that to the ally- shes gonna have problems at 150,000ish it you don't do basic filter changes.

Modern transmissions in many cars extend their life by being completely sealed. By not venting and not having a dipstick it keeps out dirt and most importantly moisture. I know a big part of that is the difference in oil, but I wonder if that technique would make the 4l80 last even longer. Imagine a pickup that tows heavy getting 300,000+ miles and never needing filter or oil.

My wife's 4Runner has one of those never service transmissions. They also spec Toyota WS (World Standard) Automatic Transmission fluid, which costs $60/quart. **** that. I've done a complete flush and put in Valvoline Synthetic transmission fluid. Truck is at 227K miles. Most of the Toyota guys are Soy Boys who use Toyota fluids and get their nails done while discussing blacking out emblems and adding aftermarket skid plates.

 

[Will L.]

Yeah, I signed up on a forum for the wife’s 07 fj cruiser and eventually might go read something there again, if it breaks and I taxkle it rather than a shop. So much group think and “if Toyota engineers made it, it is the only answer” haha-
When they see the upgrades hers has and I dont worship at their alter- it’s hilarious how they react. Best part was when they were commenting how great we were doing off road and they commented how it is unstoppable, and my wife said- yeah we just will save the hard areas for the hummer. Haha. Geez man, its a rig and they all have their problems- get over it, They don’t get it.