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| | | | Joined: Apr 2010 Posts: 18 New Guy | | New Guy Joined: Apr 2010 Posts: 18 | hello all, thanks for all your help - i'm learning more and more each day!
I would like to make my '51 1-ton FB more of a "driver" and not so much a work truck and wanted to know where to start?
I'm assuming I'll have to change the gear-ratio in the rear end but don't know where to begin and how to even tell what the current ratio is.
Any help on this would be most appreciated! | | | | | Joined: Apr 2005 Posts: 187 Shop Shark | | Shop Shark Joined: Apr 2005 Posts: 187 | 514 if it's stock,if you have the Eaton rear,you can change out the center section with a 3/4 and get a 457 gear.
_____________ Floyd If we choose being kind over being right,we will be right every time. Knowledge is a poor substitute for experience. Remember what is precious to another, may not be to you, but it is precious nonetheless. 1948 Chevy 2-Ton | | | | | Joined: Apr 2010 Posts: 18 New Guy | | New Guy Joined: Apr 2010 Posts: 18 | Thanks Floyd! Here is a picture of the rear housing and the serial # on the side - a link to these pix, not sure if that'll help. It is stock, 100% Rear End and Serial # | | | | | Joined: Oct 2004 Posts: 1,780 Master Gabster | | Master Gabster Joined: Oct 2004 Posts: 1,780 | I am not an expert on these, but if the rear end will accept the 1967-1972 eaton 3/4 rear differential/pumpkin, you should be able to install 4;11 gears. Here's the same rear end that Denny had and I think he changed his out to the 4:11 from the 67/72 3/4 or 1 ton truck.
AXLE IDENTIFICATION
denny graham how-to photo's
This information should be helpful to those that are looking for the eatons.
From Bill: (Longbox55):
There will be a code stamped on the front face of the carrier. I've posted the codes before, but for sake of saving a ton of searching for them, here they are again.
1967; HW, JU. These are listed as 4.11, may be Spicer rather than Eaton
1968; NA, NB, WI, RN (RN is listed as a 1 ton diff)
1969; NA, NB, OT, OW, OY, TF. There are also 1 ton listings; IE, LJ, LZ, MR, NZ, RN.
1970; TAA, THU, THW, TJU, TLN, TMZ, TNA, TNB, TOT, TTF, TWI.
1 ton; TIE, TIH, TLJ, TLX, TLZ, TMR, TNZ,TRN.
4x4 K20; TPW, TPX
1971; TAH, TAJ, TJA,TJB, TJP, TJS, 2G.
1 ton; TAK, TAL, TAP, TJK, TPZ.
4x4; TJH, TJJ,TKB, TKC, TKK, TKL, TKS, TKT.
1972; RAH, RAJ, RJA, RJB, RKK, RKL, RKS, RKT, RJP, RJS, RKB, RKC.
1 ton; RAK, RAL, RAK, RAP, RJK.
4x4; RJH, RJJ.
I do have listings for a 3.54 ('71 and '72) and a 4.11 ('67-'72). but from what I understand, those are Spicer differentials rather than Eaton, though I have seen a '72 with a 3.54 code on an Eaton differential.
BTW, most, if not all, GMC trucks from the '60s used a Spicer differential in the rear, either a Spicer 60 or 70 (I've seen them both ways).
_________________________ | | | | | Joined: Mar 2002 Posts: 9,115 'Bolter | | 'Bolter Joined: Mar 2002 Posts: 9,115 | I installed a 71 3/4 rearend gearset in my 1951 1 Ton. It has very tall 16" tires and the engine turns at 2700 rpm at 60 mph. The ratio of the new set is 4.10. I am happy with this and most of my higher speed driving is done at 50 mph but I occasionally go 60 without any problems. | | | | | Joined: Dec 2010 Posts: 24 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2010 Posts: 24 | Does anybody know anything about the G87 power-lok rear diff. option that was available in say a '71 3/4 ton? Would this gear set bolt into my "52 3600?
Terry
'52 Chevy 3600
'03 Chevy 2500HD
'64 Pontiac Grand Prix
'93 Jeep Wrangler
| | | | | Joined: Oct 2011 Posts: 34 New Guy | | New Guy Joined: Oct 2011 Posts: 34 | From what i see the 1967-1972 chevy and gmc trucks had Eaton or Dana rearends , i found myself online for sale a 1967 chevy one ton truck the GVW on the Vin plate is 10,000 lbs the wheel base is 133 inch , im thinking the rear grearing is 514 but i was thinking about 411 or 457 , i want to be able to go on the highway with a trailer at 65 or 70 not at 45 or 50 , how hard is it to change a rearend grearing,chuck , there is a 67-72 chevy&gmc one ton truck its wheel base is a 147 inch the GVW for that is 14,000 lbs rearend grearing is 617 | | | | | Joined: Oct 2011 Posts: 34 New Guy | | New Guy Joined: Oct 2011 Posts: 34 | Sorry mess up at the end i ment to say. there is a 67-72 chevy&gmc one ton truck its wheel base is a 157 inch the GVW for that is 14,000 lbs rearend grearing is 617 | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Up to '72 or so, 3/4 and 1 ton w/ automatic trans had higher ratios, 3.73?
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Apr 2005 Posts: 396 Shop Shark | | Shop Shark Joined: Apr 2005 Posts: 396 | Doc, From your picture it is a "Eaton" rear(round rear cover) and if stock it is a 5:14 ratio.36 ring gear teeth,7 pinion gear teeth. You should be looking for a third member,Pumpkin/ Gearset from a 1967thru 1972 chevy/GMC 3/4 ton or 1 ton with auto tranny. The gear set will bolt right into your axel housing. It will have 37 ring gear teeth and 9 pinion gear teeth. If you request, I can send a pic of the ring /pinion part number. I have it somewhere in my Pic file. Good luck with your search for this pumpkin. I sold one back in march,2011 for $350.00 plus $130 shipping and have seen them advertised at $450. Jerry.
Jerry
| | | | | Joined: Nov 2009 Posts: 220 Shop Shark | | Shop Shark Joined: Nov 2009 Posts: 220 | Gotta chime in here.
My truck is a '59 Apache 3600 - 3/4 ton - that came with 4:56 gears in the Eaton rear end. I wanted a truly highway capable truck, so I ended up swapping out the entire rear end for a Dana 60 rear from an '87 Dodge 2500. I got 3:54 gears, so the truck can run on the highway all day and not break a sweat. Pretty much a bolt-in operation except for modifying the spring perches. The Dana is about 3" wider than the Eaton, but the tires still clear the fenders with no problems.
Worth considering.
Chris | | |
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