rearend id

[thomasbailey]

i have an 81 k10 customdeluxe was my grandpas. he bought it new im trying to get info on this thing. the rearend has a strange code i havnt been able to decode yet RCH 062W11. i would use the glove box code but has long since been faded out. what i wanna know is the gearing thats in it. yes i know that i could have been changed but seeing as my grandps lost his feet in 1986 and stopped driving it, so it sat in his shop till december when i pulled it out. the tags expired in jan 87' i doubt that the rearend was messed with. also on a side note i havnt been able to even find id codes on my front axel where would a guy look for them? i think the thing has 3.08 gearing or 2.73 cause it just has no power at all to shift with the poor straight six in it. plz any help or direction to id this gearing would be awsome. ive spent hours on this thing i even called the dealer who said sorry i have no info on it

[Keith Seymore]

I have a few thoughts:

a) Some of the guys on this site have the ability to pull RPO information from the VIN (from what I can tell). Hopefully they will chime in.

b) For $50, you can send the VIN to the GM Heritage Center archive and they will send you the actual invoice for your specific truck. It will have all the RPO information and pricing, just like the window sticker (or if you wanted to have a repro window sticker made).

Link for that is here: http://www.gmmediaarchive.com/?page=3

c) The base axle ratio is often not shown or called out on the service label. If you can give me more details about your engine/trans combination I can post the powertrain chart for your type of truck and we can determine what the base combination would have been.

K

[Keith Seymore]

I already had an 81 Powertrain chart pulled up, so here it is:



RPO GQ1 represents the base axle ratio.

You can see that for K10 the lowest (numerical) gear offered for the 6 cylinder is the 3.42 with an auto trans or manual 4 speed (3.73 was optional in this case); the 3.73 was base with the Saginaw 3 speed.

K

[ElGracho]

Pull the cover and read the tooth counts off the ring gear. If you've already spent hours, you'd be done already. It probably needs an axle oil change anyhow.

[thomasbailey]

yea thanks for the info it has the 250 with the sm465 4 speed the poor truck just doesnt have the power to move out of its own way. in 4x4 i cant even shift into 3rd no matter how fast i may be going. also has the 208c transfer case. yea i wanna pull the cover and look but busy with work and if i found out that it has the 3.42 then id deff wanna put the 373 in it. id like to keep the 250 cause it gets great mileage around 20. so if i could just gear it a little better would be a great little truck. also on a side note is there any giudes out there for removing all the emisions hoses and crap off this engine?