Confused

[nsb29]

I ordered new gears for my 65 but when I went to install the carrier it didn’t fit, after a lot of Ass scratching I find the ring gear is 1/4 inch thicker than the old one. Summit told me I ordered the wrong one but in reality I ordered the gears for a 65C 10 1/2 ton they are the ones that determined the gear they sent me, in my research I understand that the difference is there is a series 3 and a series 4. I don’t understand why they didn’t ask me which differential I had instead of just picking one and sending it to me. my question is can anyone shed any light on what determines the two different housings and were they both available in a 65 1/2 ton. Now I have a problem with returning it as I have installed it,
so I’m looking for as much information as I can hoping to come up with a good argument as it is their mistake
Thanks for any help I can get

[SkinnyG]

Now you order the correct carrier for the ring gear you have. I'd recommend a limited slip, while you're at it.

The different carrier series relate to specific gear ratios.

What gear ratio did you have, and what gear ratio did you order??

[cwcarpenter98]

The series 4 carrier is for 3.73, 4.10, and higher numerically. The series 3 carrier is for the lower numerically than 3.73

[VictoriaHardware]

cwcarpenter98 is correct- there are two carriers (3 Series and 4 Series) and the ring gear must be compatible with the carrier. They didn't send the wrong part if that is the ratio you wanted. It would have been nice to know if what you ordered was going to work with your old carrier though, and an experienced phone jockey should have made you aware.

It looks like factory-available ratios for '65 C10s were 3.07, 3.73, and 4.11 . So both 3 & 4 Series carriers came in '65.

If you are attempting to go to a 3.42 or 3.08 gear and your old carrier was a 4 Series, then you're not out any money, just time and aggravation.

[nsb29]

It was an original 373 limited slip I ordered a new set of 373 gears I replace the original limited slip when I did the chassis originally and used my original gears but had someone else do the work. I drove my truck to Southern California from Florida by the time I got here it was screaming pretty loud, I found the nut on the end yoke Head back off and there was significant wear on the pinion spline I decided to replace everything I am not a differential guy and did not realize that it was the carrier that was different. But obviously I had the correct Limited slip carrier for the thin gear. Yes you’re right the guy on the phone should’ve asked me what carrier I had thanks for the help
I’m doing this one myself

[SkinnyG]

This isn't making sense.

A 3.73 requires a Series 4 carrier. If you pulled off a 3.73, you should be fine putting a 3.73 in its place.

UNLESS you told them that you had a Series 3 carrier, or Summit expected there to be a Series 3 carrier in there, in which case Summit might have sent thicker gears to fit the 3.73s into the "wrong" carrier.

[cwcarpenter98]

Could it be that the Summit guy set you up with a car 12 bolt gear set? I'm not up to speed on the car rear ends, so I'm not sure if they have different gear sets

[nsb29]

I’m more confused than ever they’re sending me another gear set I have no idea what I’m going to get I gust hope it works

[LostMy65]

What's the part numbers for both the wrong one and the one they are sending you now?

[nsb29]

Well if the one that’s on it’s way ever gets here I’ll find out the one I already have is at a friends shop where I’m working on the truck at I hope the one they are sending cums today and I will be able to work on it tomorrow I’m trying to get home for Christmas LMAO this could not have happened at home where I had time to figure it out I just looked at tracking and it still sitting in LA so I don’t think I’m going to get it today sh!?

[LostMy65]

Here's a thread on car vs truck
http://67-72chevytrucks.com/vboard/s...d.php?t=575791

[nsb29]

Well summit sent me gears for a car these people have no idea what they are doing my original gear is a 373 truck series 3 ring gear # 3864623 Gm 11 54/ 1141 with matching pinion so chev did made 373 with a thin ring gear

[LostMy65]

It's too bad they don't know to ask those questions. I can see you saying 12-bolt and them thinking car 12-bolt.
Odd thing is, when I go to a local parts store they ask me what vehicle, what year, and even what engine when I need something as simple as a 12-bolt cover gasket. Strange they didn't at least ask you what vehicle.

[nsb29]

When I originally ordered it I told them it was for a 65 c10 short bead I didn’t know there was different carriers. when I bought the new carrier I gave them the same information there wasn’t any thing about series 3 or 4 and it fit my original gears.
When I got the thick gear and it didn’t fit I called them and that’s when I was told I had a series 3 career, well when it finally got here at first it looked ok 81/2 “ 12 bolt but not the same thickness as the original one but when I dropped it over the carrier it didn’t fit the hole seemed to small, my first thought was it was a for a car but when I cooled off I looked it up and among other trucks it fits 65 c10s the part # rmg12bt373 this just doesn’t make sense how many different carriers did they make
I agree they don’t ask enough questions

[nsb29]

Well I’m finally home back in Florida I ended up using my old gears with new bearings and a new end yoke, now I’m in my on garage I can figure this out.the first gear was for a series 4 carrier and was 1/4 in thicker than my original, so they sent me another set and according to the numbers it’s for a series 3 Carrier for my year truck but it’s a 1/4 thinner than my original it’s like wtf is going on.
Apparently 373 was available in bought series 3 and 4. Also it seems Richmond gears are trying to cover too many years with one gear. Well update this once I figure this mess out but right now I believe it would take a1/4” shim to get the ring gear to meet the pinion this is stupid