88GMCtruck
I'm all 8-Luggy!
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The 11k trucks were RPO 9D6 - CHASSIS 11,000 LBS, GVW.
I did a bunch of reading in the GM hertiage center documents, and the regular pickups only go to 10k. No mention of higher GVW for a standard pickup, and 11k and 12k are something only shown in the Chassis Cab trucks. Additionally, I cannot find (in this searching of 98 documents) the listed RPO 9D6 for the transfercase, only mention of F44 tied with GVW RPO codes C7E and C7L for 11k and 12k, respectively. Just as GM guy mentioned, 11k is 2wd and 12k is 4wd, so I'm not fully sure how the RPO 9D6 ties back to a 4wd 11k truck....
The only part I can find linked to this RPO is the transfercase, of which is a Borg Warner variant. I have one installed in my 98 dually because it is both A: what was available when mine gave up the ghost and B: is in theory, stronger. You can see more about that in my build thread :http://www.gmt400.com/threads/88gmc...pig-build-black-fox.20243/page-40#post-939480
There isn't much information on these BW cases on the internet, it took me a solid week to fully understand them and their applications.
A partial snippet of info from that thread: "GM used 3 BW cases in these trucks. BW1370, BW4401, and BW4470. My truck has a BW4401. It's a predecessor of a BW1370 (they actually share a ton of parts, and half of the case even says 1370 on it). They used the BW4470 in Chassis Cab trucks which were rated at 12,000 GVW. There is also a heavier version of the BW4401, for crewcab longbed trucks outfitted with RPO 9D6 (11,000 GVW). Both the BW4401 9D6 and the BW4470 use a 1.5" wide chain and gears as opposed to the 1.25", and the BW4470 has a fixed oil pump housing plate which the others do not have. To make it even more confusing up front there are flange (early) and fixed yolk (late) outputs, and in the rear there are slip yolk outputs for early regular cabs, and fixed yolks for the rest."
I did a bunch of reading in the GM hertiage center documents, and the regular pickups only go to 10k. No mention of higher GVW for a standard pickup, and 11k and 12k are something only shown in the Chassis Cab trucks. Additionally, I cannot find (in this searching of 98 documents) the listed RPO 9D6 for the transfercase, only mention of F44 tied with GVW RPO codes C7E and C7L for 11k and 12k, respectively. Just as GM guy mentioned, 11k is 2wd and 12k is 4wd, so I'm not fully sure how the RPO 9D6 ties back to a 4wd 11k truck....
The only part I can find linked to this RPO is the transfercase, of which is a Borg Warner variant. I have one installed in my 98 dually because it is both A: what was available when mine gave up the ghost and B: is in theory, stronger. You can see more about that in my build thread :http://www.gmt400.com/threads/88gmc...pig-build-black-fox.20243/page-40#post-939480
There isn't much information on these BW cases on the internet, it took me a solid week to fully understand them and their applications.
A partial snippet of info from that thread: "GM used 3 BW cases in these trucks. BW1370, BW4401, and BW4470. My truck has a BW4401. It's a predecessor of a BW1370 (they actually share a ton of parts, and half of the case even says 1370 on it). They used the BW4470 in Chassis Cab trucks which were rated at 12,000 GVW. There is also a heavier version of the BW4401, for crewcab longbed trucks outfitted with RPO 9D6 (11,000 GVW). Both the BW4401 9D6 and the BW4470 use a 1.5" wide chain and gears as opposed to the 1.25", and the BW4470 has a fixed oil pump housing plate which the others do not have. To make it even more confusing up front there are flange (early) and fixed yolk (late) outputs, and in the rear there are slip yolk outputs for early regular cabs, and fixed yolks for the rest."
