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Regular
Posts: 63
Location: Eagle, Idaho | I have a 2005 3/4 ton Chevy Silverado diesel HD truck with automatic transmission. The retarder works great if I'm going above 45 mph and begin a down hill descent. It will then kick in if I tap the brake and will hold my speed down. However, if I'm traveling at say 30 mph and want to keep my speed low the retarder doesn't appear to work. I can shift into the lower gears but the truck just keeps going faster until I brake.
Any ideas about this issue? |
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Expert
Posts: 1416
 
Location: sc | The torque converter unlocks around 25 mph, that would cause what your're feeling at the slower speeds. You are allowing the engine to rev in the grade brake zone of 3200-4800 rpm? |
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Expert
Posts: 3802
 
Location: Rocky Mount N.C. | Originally written by apricotbend on 2010-05-24 12:52 PM
I have a 2005 3/4 ton Chevy Silverado diesel HD truck with automatic transmission. The retarder works great if I'm going above 45 mph and begin a down hill descent. It will then kick in if I tap the brake and will hold my speed down. However, if I'm traveling at say 30 mph and want to keep my speed low the retarder doesn't appear to work. I can shift into the lower gears but the truck just keeps going faster until I brake. Any ideas about this issue? Get the idea out of your head that it is a "retarder", it's far from it. Like Chad said, it's a locked torque converter until you get below 25 mph, then it releases. Works whether the truck is in tow/haul or not, it just kicks in sooner and holds longer in tow/haul. Be sure you're using the tow/haul mode, that's where it really works the best. This is a "retarder"..... http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA2953EN.pdf |
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Regular
Posts: 63
Location: Eagle, Idaho | Chad and Retento---Thanks for the education. I have been driving this rig since 2005 and pulling an 8 foot short wall 2 horse LQ. The trips I make don't have really steep grades but I was considering the possibility of traveling steeper grades. Doesn't sound like a good idea??? I haven't ever red lined this truck. Wish I had better braking capability below 25 mph. Are there any after market additions that would allow better braking below 25??
I'm sure my questions sound elementary to you but appreciate the education. |
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Expert
Posts: 1416
Location: sc | When you say redlined, are you talking about the dashed or solid redline? I let mine hover around 4000 rpm with heavy loads/big hill, works pretty good on this side of the country. An exhaust brake will give more slowing power, they are not recommended for our trucks, but people use them. Click over the the dieselplace.com, you should be able to easily find people on your side of the country and what they're using. |
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Expert
Posts: 1416
Location: sc | Well that didn't show up right; http://www.dieselplace.com/forum/ |
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Allison Transmission Retarder
