dont know which series my carrier is - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68c10ratrod · 03-20-2015, 12:34 PM

im looking to put a posi in my truck. i'm not exactly sure which series i have now but i have 3.73 gears and would like to keep it that way. i was wondering if a 4 series posi would fit in a 3 seires

**68350** · 03-20-2015, 12:38 PM

3.73 gears are a series 4 carrier. The different carriers cover a set of numerical gear ratios

68c10ratrod · 03-20-2015, 12:49 PM

Quote:

Originally Posted by 68350

3.73 gears are a series 4 carrier. The different carriers cover a set of numerical gear ratios

alright cause the guy i got the truck from said it was a 3 series. but as i looked in to it, it didnt make sense cause the was a high gear for 3 series

bonnieclyde100 · 03-20-2015, 01:34 PM

they make 3.73 that will fit a 3rd series carrier. my truck originally had a 3.08 in it and I ordered a 3.73 that fit the 3.08 carrier. it is a Richmond I bought from summit racing so it is possible you have the same thing.

**67 cst swb** · 03-20-2015, 01:45 PM

A variety of companies make both a 3 series 3.73's and 4 series 3.73's.
But OEM only had 4 series 3.73's.
If the previous owner rebuilt the rearend with a 3 series 3.73 to go on an originally numerically lower gear. Then you may need to check it out first.

*Fitz* · 03-20-2015, 02:12 PM

Quote:

Originally Posted by 68c10ratrod

im looking to put a posi in my truck. i'm not exactly sure which series i have now but i have 3.73 gears and would like to keep it that way. i was wondering if a 4 series posi would fit in a 3 seires

Identifying which series carrier you have is determined by measuring the distance between the face of the ring gear flange to the bearing seat on the ring gear side as shown in the photo. Series 4 has the greatest distance, series 3 in the middle and series two the least.

**67 cst swb** · 03-20-2015, 03:04 PM

Quote:

Originally Posted by Fitz

Identifying which series carrier you have is determined by measuring the distance between the face of the ring gear flange to the bearing seat on the ring gear side as shown in the photo. Series 4 has the greatest distance, series 3 in the middle and series two the least.

Excellent information Fitz !

68c10ratrod · 03-20-2015, 11:12 PM

Quote:

Originally Posted by Fitz

Identifying which series carrier you have is determined by measuring the distance between the face of the ring gear flange to the bearing seat on the ring gear side as shown in the photo. Series 4 has the greatest distance, series 3 in the middle and series two the least.

Thank you fitz. That's good stuff. I learn a lot on this forum

03-20-2015, 12:34 PM	#1
68c10ratrod Registered User Join Date: Mar 2015 Location: Centreville, MD Posts: 20	dont know which series my carrier is im looking to put a posi in my truck. i'm not exactly sure which series i have now but i have 3.73 gears and would like to keep it that way. i was wondering if a 4 series posi would fit in a 3 seires

03-20-2015, 12:38 PM	#2
68350 Senior Member Join Date: Jan 2002 Location: Williston, ND Posts: 2,999	Re: dont know which series my carrier is 3.73 gears are a series 4 carrier. The different carriers cover a set of numerical gear ratios __________________ 68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi

03-20-2015, 01:34 PM	#4
bonnieclyde100 Registered User Join Date: Jan 2012 Location: Henderson,TX Posts: 336	Re: dont know which series my carrier is they make 3.73 that will fit a 3rd series carrier. my truck originally had a 3.08 in it and I ordered a 3.73 that fit the 3.08 carrier. it is a Richmond I bought from summit racing so it is possible you have the same thing.

03-20-2015, 01:45 PM	#5
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: dont know which series my carrier is A variety of companies make both a 3 series 3.73's and 4 series 3.73's. But OEM only had 4 series 3.73's. If the previous owner rebuilt the rearend with a 3 series 3.73 to go on an originally numerically lower gear. Then you may need to check it out first. __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White 2002 Chevrolet 1500HD 4x4 Crew Cab 6.0L 4L80E Red



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