Discussion in 'The Garage' started by big_truxx, Apr 25, 2005.
Just like it says poll about an idea sparked by another post
GV??? whats this?
Why would you run a 700 and a GV concurrently? No way a 6.2 or many other engines for that matter could lug that low and still give good economy and power.
Gear vendors OD.
With a diesel engine this might be interesting. What engine RPM's would you be getting at freeway speeds with the dual OD?
I would imagine with some 4.10's or 4.56's, 31" tires and the 700R4, the 6.2 could probably get the Suburban moving pretty well, and the 700's OD might be useful in around town situations, then for freeway you'd have the GV unit to add to that.
Played around over at 4lo.com, looks like 31's, .70 OD (700R4), and 4.56 gears you'd be turning 1200RPM at 35MPH. Sounds REALLY low, but with the 6.2, that might be no problem? 3rd gear (1:1) would net you about 1600RPM, ok for 35MPH hill climbing diesel folks?
If I've got my math right, same setup at 60MPH using both OD's, would net you 1600RPM.
I'm sure some of the 6.2 runners have some input on how that would "feel" trying to push one of these trucks at those speeds, at those RPM's.
My setup (355, 465, 3.42, 33") turns almost the exact same RPM's at 35MPH as the above theoretical, and it's not a problem typically (on flat ground) so I don't see why the diesel would have a problem. Still, 4.56's would be a necessity I'd think, 3.73's put you down to almost 1000RPM at 35MPH.
For strictly an on-road truck, I don't suspect those RPM's are that unworkable, and it's not like you don't have a 3rd gear if necessary.
Really sounds like an overall expensive, perhaps unnecessary combination, but as long as MPG increases end up being decent or possible, maybe it would be worth it. Fun to play with, just expensive to put in practice and test. But really, the diesel folks here probably end up with similar final drive ratios at least in some situations, and will have some input.
I think it would be over kill, you could use it when you go down hill
This site has a lot of good info
Sorry I didn't read to the last choice
I would recomend goin with a th400 unless you are running with BIG-TIME torque like 600 plus ft. lbs. (and that would destroy a 700r4).
I was bored, curious and off in space as I am trying to figure out how divorce paperwork works. long story involving kelly saying was waiting on me to get home and had papers waiting for that then didn't have the money... but had papers waiting... anyway was just a thought. I didn't think it'd work/be practical but one never know and it don't hurt to ask that's how everyone learns.
I was reffering to the burb project I would like to work on. 6.2/700 3.08 or 3.42 gears 1/2 ton 2wd. It will be for hauling family/groceries/errend running only. I have a crew dual for "working".
my 6.2 with a banks turbo, 3.08's and 31's didn't have enough power to keep it in overdrive untill you were past 70. That was something like 1540 rpm, the overdrive in a 700 is .7 not .75 like a 4l80e.
The numbers I posted were figured right, just wrote the wrong ratio down. Fixed now.
3.08's or 3.42s I'd have to say hands down no way is a dual OD setup going to work. Well, maybe if you put some 13" tires on there lol.
I run a 6.2L/TH400/3.21 and 33's on my DD Burb. It is a drag around town, but cruises nicely on the highway. I know if went a step taller on gearing it would suffer big on overall driveability.
IMO the TH700 offers plenty of gear range for good economy in a DD vehicle.
I had a burb 350/700/3.73 on 38's and got it up to 128 mph or so my buddy tailing me in his mustang says..... glad I'm still around to talk about it
Didnt see the last choice either.
I have a 83 2wd burb with the 700 and 3.08 gears. Its fine, I wouldnt bother adding a GV unit to it at all. The tall first gear gets you going, and the OD keeps you there.
BTW, if your not able to use OD until 70, there's something seriously wrong there. Mine will shift into od at like 40, and not kick out unless Im going up hill or punch it. I have no problems crusiing on the highway (flat to mild hills) at 55-60 in OD.
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