randygall Posted August 8, 2008 Report Share Posted August 8, 2008 I have a B-2D-126 with 215/85-16 tires. the gear I have now is 4.89 to 1. I am wanting to drive this truck on a long trip next year, but I need to at least be able to do the speed limit. Other gearing avalible were 4.3 to 1 and a 3.9 to 1. I have check and been unable to find ring and pinions for this rear end. Are they still availble? Also any advice on the gearing that I should run would be helpful. I plan to pull a 3500 lbs trailer. I know that higher gearing would give me faster speed, but I dont want it to die on hills. Thanks for any help Quote Link to comment Share on other sites More sharing options...
Dennis_MN Posted August 8, 2008 Report Share Posted August 8, 2008 I am wanting to drive this truck on a long trip next year, but I need to at least be able to do the speed limit. The way our politicians are reacting to our high gas price will be to lower the speed limit to 55. You can be like them --- Just do nothing. Dennis:) Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted August 8, 2008 Report Share Posted August 8, 2008 I have a B-2D-126 with 215/85-16 tires. the gear I have now is 4.89 to 1. I am wanting to drive this truck on a long trip next year, but I need to at least be able to do the speed limit. Other gearing avalible were 4.3 to 1 and a 3.9 to 1. I have check and been unable to find ring and pinions for this rear end. Are they still availble? Also any advice on the gearing that I should run would be helpful. I plan to pull a 3500 lbs trailer. I know that higher gearing would give me faster speed, but I dont want it to die on hills. Thanks for any help[/quoteYou should be able to pull the hoghead (3rd member) and swap in another say 3.9 or 4.1 hoghead, those might give you the best of both worlds, some pulling low end power, and less rpm on the highway. The older diffs have 10 spline axles, the newer 1950s, have 16 spline axles, if you find the right hoghead, it's a fairly straight forward easy swap. Is this truck a 1/2 or 3/4 ton, that would make or could make a difference in swapping? Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted August 8, 2008 Report Share Posted August 8, 2008 With thiscurrent diff ratio 4.89, and P215 85 16 tires, around 30.4 inches tall, at 55 mph, your engine would be turning at 2972 rpm. 4.89 diff ratio 30.4 inch tire @60 mph 3242 rpm @65 mph 3513 rpm 4.11 diff ratio 30.4 inch tire @55 mph 2498 rpm @60 mph 2725 rpm @65 mph 2952 rpm You can calculate this yourself at www.4lo.com ..........Fred Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted August 8, 2008 Report Share Posted August 8, 2008 The 1 ton axles are different enough from the 1/2 ton and 3/4 ton axles that finding a replacement third member is more difficult. On the smaller trucks many car diffs interchange. In fact, I have a Plymouth diff in my truck. But from what I've seen that wouldn't work on a 1 ton axle. Merle Quote Link to comment Share on other sites More sharing options...
David Muma Posted August 9, 2008 Report Share Posted August 9, 2008 That's why I was at the recyclers yesterday... found 4 one ton trucks but as they were sitting on the ground I couldn't get under to look for the ratio on the carrier.... the guy at the yard said he couldn't afford the time to lift them up and look... think I'll go back with a shovel... and a good light and see if I can't get under to find out what's there... Quote Link to comment Share on other sites More sharing options...
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