08-02-2013, 04:13 PM
|
#1 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
|
Gear swap time: Turns out I have 3.42 gears
Well I recently found out that I have 3.42 rear axle gears, throught I had 3.08 gears and a factory posi differential all along.
Here:
http://ecomodder.com/forum/showthrea...new-26556.html
It kind of makes sense, I always thought I should have been getting better highway milage.
This means there is more room to pickup some MPGs.
It also means that my 8.5inch GM 10 bolt has a serries 3 gear carrier. This allows me to use the Eaton 10 bolt posi that I picked up may years ago in my axle.
Serries 3 carriers have a wider selection of gear ratios and the gear sets are cheapest of the all the carriers.
(if I had a 3.08 rear it would be a serries 1 carrier and would have fewer swap choices, but then it would already have the 3.08s I want with a posi from the factory)
I am thinking about installing 3.08s or 3.23s.
I'm leaning towards 3.08s.
What do you think?
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
Last edited by oil pan 4; 08-02-2013 at 06:30 PM..
|
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
08-02-2013, 05:37 PM
|
#2 (permalink)
|
Master EcoModder
Join Date: May 2011
Location: Indiana
Posts: 1,194
Thanks: 112
Thanked 511 Times in 213 Posts
|
What tranny do you have again?
__________________
Diesel Dave
My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".
1 Year Avg (Every Mile Traveled) = 47.8 mpg
BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg): http://ecomodder.com/forum/showthrea...5-a-26259.html
|
|
|
08-02-2013, 06:25 PM
|
#3 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
|
Quote:
Originally Posted by Diesel_Dave
What tranny do you have again?
|
TH700R4, with a throttle value cable adjusted for firmer shifts (broke original transmission mount upon completion of adjustment) and a massivily over kill transmission filter/cooler setup.
Permalinks to my transcooler/filter build:
Remote 8 pass transcooler, with fan and sheet metal pebble guard:
Question: How to hook up a transmission cooler - Page 3 - Diesel Place : Chevrolet and GMC Diesel Truck Forums
Installed remote transcooler, plus you can see my nappa #1422 hydraulic fluid filter that I am using as my transmission filter. Its been installed since 2006 but I disconnected (bypassed) it in 2008 and I just recently replaced the filter, cleaned the filter head and put it back into service.
http://www.dieselplace.com/forum/63-...ml#post4957393
Everything else, front mount cooler, cooler loop, transmission fluid thermostat, transmission temperature gauge, remote cooler fan switch.
Question: How to hook up a transmission cooler - Page 4 - Diesel Place : Chevrolet and GMC Diesel Truck Forums
(lots of pictures)
The 700 serries has a lockup converter, 1:1 third gear, 0.71 OD and I have 31 inch tires.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
Last edited by oil pan 4; 08-02-2013 at 06:39 PM..
|
|
|
08-02-2013, 11:39 PM
|
#4 (permalink)
|
eco....something or other
Join Date: Jul 2009
Location: Colfax, WI
Posts: 724
Thanks: 39
Thanked 67 Times in 50 Posts
|
My brother has an f150 and had a 2.64 or something like that but he burned it up so I gave him a 3.08. Mileage is about the same. The 2.64 was hard to get going without killing it. The 3.08 is better, but I like my 3.55 for all around work power.
__________________
1991 F-250:
4.9L, Mazda 5 speed, 4.10 10.25" rear
|
|
|
08-03-2013, 08:29 PM
|
#5 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
|
I ran the numbers on a TH700 transmission, 31'' tires with 2.56 gears (GM 10 bolts tallest production ratio) a few years ago, it wouldn't work very well.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
|
|
|
08-05-2013, 04:36 AM
|
#6 (permalink)
|
Exceptional Member
Join Date: Jan 2011
Location: Pennsylvania
Posts: 166
Thanks: 27
Thanked 15 Times in 14 Posts
|
Quote:
Originally Posted by oil pan 4
I ran the numbers on a TH700 transmission, 31'' tires with 2.56 gears (GM 10 bolts tallest production ratio) a few years ago, it wouldn't work very well.
|
I don't think it would be a problem with the low end power in the diesel. I had an 85 caprice coupe with 2.56 gears and a 700R4. I put the springs from the police package on and had to run 225/75/15s to fill in the gap. That's 28.3" tire. The first gear in the 700r4 will get anything moving quickly and on the highway it would cruise with almost no throttle. You would be turning 100 rpm less than I was at 55 mph with your tire difference.
__________________
Don't know why it says 00, it's a 95
374,000 miles and tired.
Last edited by YukonCornelius; 08-05-2013 at 04:44 AM..
|
|
|
08-05-2013, 11:25 AM
|
#7 (permalink)
|
Banned
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442
Thanks: 1,422
Thanked 737 Times in 557 Posts
|
Overdrive would be a better way to go, IMO. That much mass -- loaded for work and/or towing -- is going to suffer disproportionately in acceleration events with a 3.08, even with a hotrodded motor.
An NV-4500 trans would interest me more than the proposed gear change.
|
|
|
08-06-2013, 02:32 AM
|
#8 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
|
An NV4500 would be pretty cool but they are kind of hard to find and expensive.
Plus I don't really want to do a flex plate to fly wheel swap, my rotating assembly is machine shop balanced.
I know of the gearvender over drive units but at $2k its way out of my price range.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
|
|
|
08-06-2013, 08:46 AM
|
#9 (permalink)
|
Master EcoModder
Join Date: Dec 2012
Location: ff
Posts: 459
Thanks: 59
Thanked 38 Times in 30 Posts
|
I don't think it would be a problem with the low end power in the diesel. I had an 85 caprice coupe with 2.56 gears and a 700R4.
I agree the numbers work with a diesel and your trying for max mpg not towing.
A simple shift kit and perhaps redline clutched 700 is a very nice match for your issue. but beware the speed issue.
Should roll on well with grunt powered diesel idleing at 50 mph.
|
|
|
08-06-2013, 03:47 PM
|
#10 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,268
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
|
My best friend has a half ton GM 10-bold rear end up under his 1982 chevy pickup truck bed trailer and it has 2.56 gears.
Only problem is he lives in Virginia.
I still expect to do some towing. Just not enough towing to justify having 3.42 gears all the time.
I also drive off road but not enough to justify 4wd or 3.42 gears (that's why I have a 2wd). I would like to keep AT tires on the back at least and get the eaton posi in there.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
|
|
|
|