The biggest difference is the # of mounting bolts between the flexplate and torque converter... 3 on gassers and 6 on diesels. This alone is the biggest reason for switching. Less chance of destroying the flexplate from the harmonics.
CK5
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turbo'd 6.2 power
- Thread starter guz71
- Start date
guz71
1/2 ton status
I have always heard just the torque converter and governor gear are different, this is the first time I have heard about the valve body being different. Are the valve bodies different?, if so can the one in my gasser 700 just be used? That is something I dont want to mess with and taking it to a tranny shop would add a big expense to the swap.
I am running 38's with 4.56's in the axles, it has about 4 inches of lift so its not riduclously tall either. On flat road the truck will hold 75 all day with no problem(no shifting and TC lock up). If theres a head wind of more than probably 10 its going to knock my speed down to about 65 or less. It will go up small hills in OD and hold the speed, but anything substantial is going to make it drop into 3rd. So in OD at 70 I am turning right at 2000 RPM, which isnt to bad but 5.13's probably would help out some. With a big heavy rig and an anemic motor, a 200 rpm jump probably wouldnt do much IMO. I think the way it is setup no would work pretty good with a diesel, as far as power vs. economy.
I am running 38's with 4.56's in the axles, it has about 4 inches of lift so its not riduclously tall either. On flat road the truck will hold 75 all day with no problem(no shifting and TC lock up). If theres a head wind of more than probably 10 its going to knock my speed down to about 65 or less. It will go up small hills in OD and hold the speed, but anything substantial is going to make it drop into 3rd. So in OD at 70 I am turning right at 2000 RPM, which isnt to bad but 5.13's probably would help out some. With a big heavy rig and an anemic motor, a 200 rpm jump probably wouldnt do much IMO. I think the way it is setup no would work pretty good with a diesel, as far as power vs. economy.
It'd definitely help. With a gas motor you're actually a bit undergeared now. 4.88's would be about perfect if I remember correctly since you have an OD.
Mine does great around town with the 4.56's and 38's but past about 60mph you can tell an OD would be nice. Don't have a tach but at what I believe is 70 it's roaring pretty good.
Mine does great around town with the 4.56's and 38's but past about 60mph you can tell an OD would be nice. Don't have a tach but at what I believe is 70 it's roaring pretty good.
MaxPF
1/2 ton status
Diesel and gasser TC's are the same. They even have the same GM part #.
BKinzey
1/2 ton status
Are you sure? That doesn't follow what I've read. Unless you mean only the lock-up speed is different. I find TCs fairly confusing anyway
Lockup control is all external to the torque converter. It can be controlled in different ways, but in stock form it's a combination of throttle position, which gear the trans is in, and status of the brakes being applied (or not).
Whatever the control method, there is a solenoid that controls a hydraulic valve. If this solenoid (located in the main transmission case) is energized with 12 volts, the torque converter locks up.
I run my lockup via a manual switch (interrupted by the brake light switch). I can lock up in any gear at any speed.
Whatever the control method, there is a solenoid that controls a hydraulic valve. If this solenoid (located in the main transmission case) is energized with 12 volts, the torque converter locks up.
I run my lockup via a manual switch (interrupted by the brake light switch). I can lock up in any gear at any speed.
guz71
1/2 ton status
Thats similar to my setp, I have a toggle switch that interputs the 12v running to the solenoid, but since its grounded through the 4th gear pressure switch I can only "make" it lock up in OD.
Yea when shes drop into 3rd at 70 shes making some noise, I think its around 2600 rpm or so. On paper and what not 5.13's would make a big difference but I would like to a real world comparison. With so much drag, weight, and wind resistance I wonder if it would really do anything. I guess its not really the same because its slipping and causing friction, but when I unlock the TC at highway speeds it will make the rpm's jump up a few hundred. It pretty much does nothing as far as power goes, if I need more umph its going into 3rd. 5.13's would increase my rpm's just a little bit more than 200 at 70. So I would like to see a test in the same vehicle, I think it would be interesting anyways.
Anyone else have any information about the valve bodies?
Yea when shes drop into 3rd at 70 shes making some noise, I think its around 2600 rpm or so. On paper and what not 5.13's would make a big difference but I would like to a real world comparison. With so much drag, weight, and wind resistance I wonder if it would really do anything. I guess its not really the same because its slipping and causing friction, but when I unlock the TC at highway speeds it will make the rpm's jump up a few hundred. It pretty much does nothing as far as power goes, if I need more umph its going into 3rd. 5.13's would increase my rpm's just a little bit more than 200 at 70. So I would like to see a test in the same vehicle, I think it would be interesting anyways.
Anyone else have any information about the valve bodies?
MaxPF
1/2 ton status
Are you sure? That doesn't follow what I've read. Unless you mean only the lock-up speed is different. I find TCs fairly confusing anyway
I looked it up at one time. It didn't give the specs of the TC, but both the 350 and 6.2 with the 700 called for the same part #.
Hossbaby50
3/4 ton status
With 38's & OD 5.13's is the right gear. I have 37's and 4.56's and when I had OD I wished I had went to 4.88's or 5.13's. When I had 4.56's and 32's it was the ****. I could run 6% grades through the CO & AZ mountains at 65mph with pedal to spare with my carb.
With 4.56's, 35's, & TPI I ran some 6-7% AZ grades at 65 with pedal to spare. With 35's & 37's I wish I would have went deeper.
My opinion w/OD:
33's = 4.56
35's = 4.88
37's+ = 5.13
Harley
With 4.56's, 35's, & TPI I ran some 6-7% AZ grades at 65 with pedal to spare. With 35's & 37's I wish I would have went deeper.
My opinion w/OD:
33's = 4.56
35's = 4.88
37's+ = 5.13
Harley
Hossbaby50
3/4 ton status
I have seen Mosesburb's CC turbo 6.2L in action. Around town and light loads it rocks a gasser any day especially with the GV. But 10K strapped behind that thing I might be willing to take a strong running SBC for pulling the weight on the highway & hills.
When Fred owned that truck he towed his K5 & popup trailer to Moab with it. On heavy grades he got down to 15-20mph and even on slight hills he would start dropping speed. I know that the 6.2L isn't really meant of HD hauling though.
Harley
When Fred owned that truck he towed his K5 & popup trailer to Moab with it. On heavy grades he got down to 15-20mph and even on slight hills he would start dropping speed. I know that the 6.2L isn't really meant of HD hauling though.
Harley
MaxPF
1/2 ton status
For a gasser those gears are fine, but a diesel wants taller gears. The idea is to keep the motor at around 1800RPM at 65MPH for the best fuel economy. I should get that with 37's, 4.56's, and the 4L60's 0.7:1 overdrive. Deeper gears will give better acceleration and towing power, but mileage goes down fast when you start twisting a diesel at higher RPM.
Hossbaby50
3/4 ton status
I am talking about gasser gears for a fair comparison to diesels. Diesel gears should be 1-2 steps down the ladder like your saying for sure.
I wouldn't mind having a 6.2L turbo for a DD motor. I actually inquired about Mosesburb's CC about a week after he bought it off Fred. I was thinking about running it for my DD to keep my Cummins lower mileage. Oh well, its a Cummins, it will last awhile.
Harley
I wouldn't mind having a 6.2L turbo for a DD motor. I actually inquired about Mosesburb's CC about a week after he bought it off Fred. I was thinking about running it for my DD to keep my Cummins lower mileage. Oh well, its a Cummins, it will last awhile.
Harley
I don't know where you looked it up but every place I looked it up, it showed different part numbers and the stall speed is about 300RPM lower for the diesel.
I drove a truck that still had the gasser TC and it shifted at noticeably higher RPM, it was good for acceleration but it slips at the take off which could possibly hurt it and the fuel economy.
1250 I believe is the factory stall rating for the diesel.
The other component that is different is the governor which also has heavier weight to switch at slower RPM's.
The valve body is no different and I did have a long dicussion with the top mechanic at Shift management inc when I was rebuilding a th400 for the diesel truck.
He also pointed out that the 6 bolt design in theory is stronger but in reality most of the tabs break off on the diesel TC, the gasser design is different and stronger, you just need to get a lower stall TC.
I still use the diesel specific 6 bolts TC because they haven't given me any trouble.
guz71
1/2 ton status
I think the way I am set, its pefect for a diesel setup. 5.13's would gain me a little over 200 rpms at 70, I honestly dont think it would make a difference in my rig. That TBI motor just doesnt have the balls cause even when it goes into 3rd its no doing a whole lot more. Thats just my opinion, deeper gears might help out like you said.
I dont want to do any towing, just be able to push the K5 down the road at 70 no problem and get better than 12mpg doing it. Going up 6-7% grades are a joke right now.
I dont want to do any towing, just be able to push the K5 down the road at 70 no problem and get better than 12mpg doing it. Going up 6-7% grades are a joke right now.
MaxPF
1/2 ton status
I looked it up in the old GM Parts Direct catalog. Now their catalog doesn't even show torque converters...
You have to be careful with the GM parts direct online catalog, it is full of holes.
MaxPF
1/2 ton status
It certainly is now. It used to be much more complete. Now, many parts (including torque converters!) aren't even listed. What a POS
