tranny advice please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cherokeejohn · 09-21-2013, 07:04 PM

It's looking like I'm gonna be either rebuilding my TH350, or replacing it with something better. My goal is to make this truck my daily driver so if a 700R4 or something else would be better, please let me know. I'm located on the east coast, in Maryland, but travel allot to N. Carolina, and southwest Florida. Better fuel millage would always be a plus but need to keep it able to tow my little Harley trailer, or small camper. So any suggestions would be great or recommendations to shops, or websites.

**chiefcfd** · 09-21-2013, 08:23 PM

I went with the TH350, but if I had to do it again I would choose the 700R. I wish I had the OD. There are models that are better than others. I can't remember which maybe someone else can tell us. Certain years are stronger and hold up better.

**truckdude239** · 09-21-2013, 08:49 PM

If towing stay with the th350 700r4s wont last long towing

hugger6933 · 09-21-2013, 08:55 PM

700R4 the newer you can get the better off you are as they made improvement the whole production run, up 94 when they went to the electric stuff and then it would be classed as a 4L60 E. the 700R will have a like a .078 overdrive so it will help on mileage but nothing will as much as making sure the truck is in proper tune. Having the timing off by a little or having the carb a little fat will kill the mileage no matter what trans and rear gear you have. The rear gear needs to be brought into the conversation as well A overdrive may not be the abosolute best thing for you or your truck if your gear is like 2:73. but will most def but a welcome benifit if you are geared 3:42 or more. Jim

71swb4x4 · 09-21-2013, 08:58 PM

I would do the 700r4 if you can. There are a TON of 700r4's that have done just fine towing, they were put in Chevy trucks for a long time. I agree with the post saying you need to bring rear end gears into the conversation. You will want a something around a 3.73 for optimal mileage. 3.42 - 4.11 would probably be just fine.

motorcritter · 09-21-2013, 09:00 PM

A well-built 700R4 can be pretty durable, if you're not hauling a lot. As was noted above, check your rear axle ratio, that might be a variable that needs 'adjusted'. Overdrive is really nice to have for most driving.
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tlcrz1972 · 09-21-2013, 11:13 PM

I'm running a 4L60E with 3.08 gears and am super happy with it. And have towed 6500 LBS plus in OD and cannot complain about takeoff or pulling abilities.

With 3.08 gears I'm turning 1600 to 1650 RPM at 70 MPH, fuel mileage 17 MPG plus.

09-21-2013, 07:04 PM	#1
cherokeejohn Registered User Join Date: Aug 2013 Location: Wasteminster, Maryland Posts: 409	tranny advice please It's looking like I'm gonna be either rebuilding my TH350, or replacing it with something better. My goal is to make this truck my daily driver so if a 700R4 or something else would be better, please let me know. I'm located on the east coast, in Maryland, but travel allot to N. Carolina, and southwest Florida. Better fuel millage would always be a plus but need to keep it able to tow my little Harley trailer, or small camper. So any suggestions would be great or recommendations to shops, or websites. __________________ 72 C/10, LWB, 5.7, Auto, with A/C F.B.I = Full Blood Indian Appalachia/Eastern Cherokee,"Tsalagi"

09-21-2013, 08:23 PM	#2
chiefcfd Senior Member Join Date: Oct 2010 Location: Cadiz, Ky Posts: 514	Re: tranny advice please I went with the TH350, but if I had to do it again I would choose the 700R. I wish I had the OD. There are models that are better than others. I can't remember which maybe someone else can tell us. Certain years are stronger and hold up better. __________________ 1972 Chevy LWB Roadster 1999 Chevy Silverado 2wd 2015 Chevy High Country 4x4 Crew Cab

09-21-2013, 08:49 PM	#3
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,238	Re: tranny advice please If towing stay with the th350 700r4s wont last long towing __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

09-21-2013, 08:55 PM	#4
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: tranny advice please 700R4 the newer you can get the better off you are as they made improvement the whole production run, up 94 when they went to the electric stuff and then it would be classed as a 4L60 E. the 700R will have a like a .078 overdrive so it will help on mileage but nothing will as much as making sure the truck is in proper tune. Having the timing off by a little or having the carb a little fat will kill the mileage no matter what trans and rear gear you have. The rear gear needs to be brought into the conversation as well A overdrive may not be the abosolute best thing for you or your truck if your gear is like 2:73. but will most def but a welcome benifit if you are geared 3:42 or more. Jim

09-21-2013, 08:58 PM	#5
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: tranny advice please I would do the 700r4 if you can. There are a TON of 700r4's that have done just fine towing, they were put in Chevy trucks for a long time. I agree with the post saying you need to bring rear end gears into the conversation. You will want a something around a 3.73 for optimal mileage. 3.42 - 4.11 would probably be just fine. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

09-21-2013, 09:00 PM	#6
motorcritter Registered User Join Date: Mar 2012 Location: Boulder, CO Posts: 350	Re: tranny advice please A well-built 700R4 can be pretty durable, if you're not hauling a lot. As was noted above, check your rear axle ratio, that might be a variable that needs 'adjusted'. Overdrive is really nice to have for most driving. Posted via Mobile Device __________________ If 'that which does not kill me, makes me stronger', then I should be Superman by now!

09-21-2013, 11:13 PM	#7
tlcrz1972 Registered User Join Date: Apr 2013 Location: Gainesville, TEXAS Posts: 658	Re: tranny advice please I'm running a 4L60E with 3.08 gears and am super happy with it. And have towed 6500 LBS plus in OD and cannot complain about takeoff or pulling abilities. With 3.08 gears I'm turning 1600 to 1650 RPM at 70 MPH, fuel mileage 17 MPG plus. __________________ 1972 Chevrolet Cheyenne LB 1/2 ton finished restoration/rebuild 1995 350 throttle body FI, 4L6E (running on modified GM wiring harness) 3.08 posi rearend, factory A/C on 134A, p/s, p/b, late 70's power windows and locks and cruise, speakers in the dash + 6x9's behind the seat, factory tilt, 40 gallon fuel tank in the bed with integrated tool box, air assist bags on the rearend, sway bar up front and much more. 1972 chevrolet SNB finished 2002, 350 TB FI, TH400, factory A/C, p/b, p/s, (FOR SALE) 1969 Chevrolet 1 ton in work, home made PTO dump bed extended frame, 350 CI , 1972 Chevrolet 3/4 ton suburban future project 1972 Chevrolet 3/4 ton p/u maybe a project one day 1966 Toyota Landcruiser my playtoy



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