Lower Gear Ratio in my dually - The 1947 - Present Chevrolet & GMC Truck Message Board Network

my85dually · 11-10-2005, 02:51 AM

I have a question. Has anyone every changed their gears in the rear-end of a dually to a less steep ratio. I have 4.10 in the rear of my dually. I wanna put like 3.25 or maybe 3.50. any ups or downs? I dont tow much with it, so thats not a factor for me. I want it to be a highway crusier.
Mike

ALSO does anyone know what Rig I can get a non-electric 4-speed auto out of, that will bolt to my 454.
thanks

SanitysBane · 11-10-2005, 08:16 PM

They went to the full eletronic 4 speeds in 92 or 94. All the ones before have a lock up TQ that you have to rig up somehow. And any transmission that will work on a small block will work on a big block. Just make shure that your flexplate has the correct bolt pattern.

u2slow · 11-11-2005, 10:14 PM

You have a dually pickup as per your avatar?

That would be a Dana 70HD axle... you can put in a 3.54 ratio no problem.

There are some odd-ball Dana 70 variants out there with numerically lower gears, (3.07 & 3.42 come to mind) but they have unique housings, so the gears won't swap.

I wouldn't bother with the TH700 OD trans. Its more work (driveshaft, crossmember, cable/linkage, etc.) and your 454 will ensure its lifespan is short.

my85dually · 11-13-2005, 12:47 AM

Thanks for the replies! So dont worry about a 4 speed auto with the 454, ok. I will be able to buy 3.54 and install them no prob, GOOD!! I value this board because of people like you! oh and Yes that is the dually I am speaking of in my avi.
thank you very much

,
Mike

Tom · 11-13-2005, 10:59 AM

You can get a non computer controlled 4L80E [what comes behind big blocks from the factory from GM] and put it in there and keep your 4.10's while still saving a good 1000rpm on the freeway. Cost in the $2500-3000 range. Either that or a normal 4L80e and put the stand alone computer managment in [about $500+ the cost of the tranny]

SSC's76 · 11-13-2005, 11:58 AM

Quote:

Originally Posted by my85dually

Thanks for the replies! So dont worry about a 4 speed auto with the 454, ok. I will be able to buy 3.54 and install them no prob, GOOD!! I value this board because of people like you! oh and Yes that is the dually I am speaking of in my avi.
thank you very much

,
Mike

Well I'd talk to Dana at Probuilt. http://www.700r4l60e.com/store/customer/home.php?cat=20 They make quite a few 700R4's that will tame your big block and they dont cost much more then having a local guy do a stock re-build. Just shoot them a message there always glad to help. A 700R4 is perfect for cruising the freeways.

11-10-2005, 02:51 AM	#1
my85dually Registered User Join Date: Aug 2005 Location: YAKIMA,WA Posts: 22	Lower Gear Ratio in my dually I have a question. Has anyone every changed their gears in the rear-end of a dually to a less steep ratio. I have 4.10 in the rear of my dually. I wanna put like 3.25 or maybe 3.50. any ups or downs? I dont tow much with it, so thats not a factor for me. I want it to be a highway crusier. Mike ALSO does anyone know what Rig I can get a non-electric 4-speed auto out of, that will bolt to my 454. thanks __________________ 1985 Silverado Club Cab Dually Viva La Dually! Last edited by my85dually; 11-10-2005 at 02:54 AM.

11-10-2005, 08:16 PM	#2
SanitysBane Registered User Join Date: May 2004 Location: Lubbock, Texas Posts: 2,121	Re: Lower Gear Ratio in my dually They went to the full eletronic 4 speeds in 92 or 94. All the ones before have a lock up TQ that you have to rig up somehow. And any transmission that will work on a small block will work on a big block. Just make shure that your flexplate has the correct bolt pattern. __________________ '96 Nissan Pathfinder '02 Firebird Trans Am. '88 K5 Blazer

11-11-2005, 10:14 PM	#3
u2slow Web Wheeler Join Date: Jan 2000 Location: BC, Canada, eh? Posts: 388	Re: Lower Gear Ratio in my dually You have a dually pickup as per your avatar? That would be a Dana 70HD axle... you can put in a 3.54 ratio no problem. There are some odd-ball Dana 70 variants out there with numerically lower gears, (3.07 & 3.42 come to mind) but they have unique housings, so the gears won't swap. I wouldn't bother with the TH700 OD trans. Its more work (driveshaft, crossmember, cable/linkage, etc.) and your 454 will ensure its lifespan is short. __________________ '66 C10 longstep - Clifford equiped '84 C20 Suburban 6.2L - awaiting 4x4 conversion '91 V3500 Crewcab - awaiting diesel swap Last edited by u2slow; 11-11-2005 at 10:16 PM.

11-13-2005, 12:47 AM	#4
my85dually Registered User Join Date: Aug 2005 Location: YAKIMA,WA Posts: 22	Re: Lower Gear Ratio in my dually Thanks for the replies! So dont worry about a 4 speed auto with the 454, ok. I will be able to buy 3.54 and install them no prob, GOOD!! I value this board because of people like you! oh and Yes that is the dually I am speaking of in my avi. thank you very much , Mike __________________ 1985 Silverado Club Cab Dually Viva La Dually!

11-13-2005, 10:59 AM	#5
Tom driving is in my blood Join Date: Dec 1999 Location: Mesa AZ Posts: 5,714	Re: Lower Gear Ratio in my dually You can get a non computer controlled 4L80E [what comes behind big blocks from the factory from GM] and put it in there and keep your 4.10's while still saving a good 1000rpm on the freeway. Cost in the $2500-3000 range. Either that or a normal 4L80e and put the stand alone computer managment in [about $500+ the cost of the tranny] __________________ -78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me.



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