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  1. #1

    Default 04 burb, 6.0L 3.73 gears 33" tires, tranny or torque converter slips...

    Hey guys,
    I recently bought a 17' fiberglass boat that I need to tow with my 2004 k2500 Burb. It's got 33" tires and 3.73 gears. The tires seem to hinder the truck when towing the boat. Once the tranny warms up after towing up and down hills it begins to slip between gear changes. Also, pressing the tow button doesn't seem to make any difference that I can tell?

    So I've considered doing a gear swap to 4.56 gears, but it's $1700!

    Want to know if I could have an issue with my torque converter, any way to test?

    Would a Black Bear tune with tranny program be an option?

    Thanks!

  2. #2
    Sr. Mechanic
    Join Date
    Jun 2011
    Location
    Tuscaloosa, AL
    Posts
    160

    Default

    I would check the torque converter first but I'm not sure what test you could do for that. I have pretty much the same setup and vehicle, 04 2500 6.0L 3.73 and 32"s. I pull my boat with ease and its 24' and when loaded is just over 5000lbs. I do have a BlackBear tune which gives me firmer shifts but never had a problem before I got the tune.
    2004 GMC Sierra SLT 6.0L 4x4
    UWS Low Profile toolbox 10% tint front and over stock back tint
    AirAid MIT and K&N airfilter
    BlackBear Performance

  3. #3

    Default

    As far as the converter goes its hard to check without the proper equipment. The tire size is hurting the entire drive train. I have the same setup ('03 burb 2500, bought it with 33" tires). My burb has a 2000 rpm stall converter. Towing my 6000lb camper over big hills last Sat. it felt like mine was slipping. Temp 220. I'm going to change filter and fluid. Synthetic oil makes a difference. I also looked at 4.56 gears. With the high stall it would possible destroy my already bad gas milage. The 33" tires reduces the final ratio to around a 3.42 gear. There is a huge difference in tow ratings between gears. Anywhere from 1000 lb to 2000 lb from what I've seen. I'm going back to 245/75R16. Maybe 265/70R16E. Wide as a 32" and same height as a stock size tire. The bigger tires are putting more strain on the torque converter making it harder to do its job. A set of 4.56 gears with 33" tires makes a final ratio very close to 4.11. I've made a Excell spreadsheet for figuring out gearing and tires size along with trans gear ratios and engine rpm. Even tells me the speed at any given rpm.
    I started running ethanol free gas 91 octane, $3.99/GALLON. Boosted mgp up to 13-14 from 11-11.5. I like it. More power run smoother
    2003 Suburban 2500 LT, 6.0l Volant cai. 3.73 gear. Mobil 1 syn oil

  4. #4

    Default

    Quote Originally Posted by irishluder View Post
    Hey guys,
    I recently bought a 17' fiberglass boat that I need to tow with my 2004 k2500 Burb. It's got 33" tires and 3.73 gears. The tires seem to hinder the truck when towing the boat. Once the tranny warms up after towing up and down hills it begins to slip between gear changes. Also, pressing the tow button doesn't seem to make any difference that I can tell?

    So I've considered doing a gear swap to 4.56 gears, but it's $1700!

    Want to know if I could have an issue with my torque converter, any way to test?

    Would a Black Bear tune with tranny program be an option?

    Thanks!
    You didn't mention it, but, Have you checked your Transmission Fluid, both for Quantity and for Quality??......one of the common issues for Slipping in Auto Transmissions, is Low Auto Transmission Fluid Level......also a Dirty and/or Clogged Automatic Transmission Filter can Impede the Normal Flow of the Fluid throughout the Transmission and cause the Transmission to Slip.



    MIKE


    99"SILVERADO
    5.3 l 3.73 l G80
    BLACK BEAR CUSTOM TUNE
    SNUGTOP l COLORMATCH l KATZKIN










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