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By SteveF100239 - 15 Years Ago
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I have a stock rearend with 3.92 gears in my 55 truck. I need to reduce highway rpms and was thinking the gearing may be the least expensive start. Can anyone tell me what gearing I should look for and where? Is there a site that sells them for my truck, or are there other axles that will bolt onto my truck? any help is appreciated. Its a 239 with a three on the tree. Thanks, Steve
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By pintoplumber - 15 Years Ago
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Steve, I have a 239 with a 3.92 rear. Are you driving faster than 65mph?
This winter I'm changing the 3.92 to a 4.27. Saturday I went out with the GPS and recorded rpm's at various speeds so I can compare them when the 4.27 is in. At 65 mph I'm turning 3000 , 55 mph 2400. When racing, at the finish line, I'm turning 3800 at about 73 mph.
3000 at 65 mph isn't bad.
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By SteveF100239 - 15 Years Ago
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Thanks Dennis, I don't typically drive faster than 65 (had it to 82 twice though) but when I am on the interstate it stinks getting passed up by everyone. Also, with my truck being so close to original (no interior insulation) and the fact that I cannot get the driver's side door to stay closed all the way, at 65 it sounds like I'm pushing 100. I would imagine that I must be turning near the same rpms as you are with having the same set-up. any reason why you are going that direction with the gears and not the other way? I am getting closer to driving it on a daily basis and was looking at lowering the rpms to ease up on the engine a little.
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By Hoosier Hurricane - 15 Years Ago
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Steve: Have you thought about putting a taller tire on the back, that will lower your rpm some. Also, road noise and wind noise from a door that isn't closed tightly will not change when you change gears, only engine sounds will change.
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By speedpro56 - 15 Years Ago
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An overdrive transmisson would solve your problem without really changing originality.
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By SteveF100239 - 15 Years Ago
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I have considered the overdrive/T-5 route and may need to go that way if the gearing change doesn't give me enough relief. I found a website from another post on the forum and they carry a set of 3:08's for my truck. My wife said Santa will bring it for me if that's what I want. I am really new to a lot of this and I certainly appreciate all of y'all advise. Is there a noticable difference in 3:08's from 3:92's? As far as the door noise goes, that striker plate just will not stay adjusted right. Even with a new plate and screws it still works loose.
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By charliemccraney - 15 Years Ago
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It will be noticeable. That change will shift your RPM down by about 750rpm at cruise speed. Make sure you don't want to haul anything if you go that route.
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By Ol'ford nut - 15 Years Ago
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SteveF100239 (12/2/2010)
I have considered the overdrive/T-5 route and may need to go that way if the gearing change doesn't give me enough relief. I found a website from another post on the forum and they carry a set of 3:08's for my truck. My wife said Santa will bring it for me if that's what I want. I am really new to a lot of this and I certainly appreciate all of y'all advise. Is there a noticable difference in 3:08's from 3:92's? As far as the door noise goes, that striker plate just will not stay adjusted right. Even with a new plate and screws it still works loose.Steve- I had the same problem with my stricker plate moving no matter how tight I was able to get it. How I finally fixed the problem was putting o rings over the bolts between the plate and the body. Never had another problem with movement. Cheap fix!
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By pintoplumber - 15 Years Ago
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Steve, I'm doing it for racing and parades. I have the borg warner R10 overdrive so going the other way doesn't hurt. With the 3.92 and overdrive it gives me about a 2.43 rear. With the 4.27, I'll be at 3.00. If you can go the overdrive route, that would be the best.
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By SteveF100239 - 15 Years Ago
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Are overdrives plentiful out there or will I be hunting for awhile? I checked the classified in this forum for R10 and didn't see any for sale. I only mentioned the T5 earlier because I've read so much about them on this site. I'm trying not to repeat too many questions that others have asked but usually when I see something close to what I need to know, it's usually referring to a car instead of a truck. I like the idea of the 3:08's lowering the rpms but I do not want to give up the ability to pull/haul with my truck.
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By pintoplumber - 15 Years Ago
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Steve, you'll find overdrive transmissions at swap meets, ebay has them sometimes. Shipping would be a factor. If possible you would want to see the sun and planetary gears inside the tranny before buying, to make sure they are not damaged. I bought one that was damaged that way.
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By junkyardjeff - 15 Years Ago
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I think a 9 inch from a 57 to 60 p/u will fit the 53 to 56s and there is alot more gears available for the 9 inch.
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By SteveF100239 - 15 Years Ago
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I may go with 3.54's to start. That would be a compromise between the 3.92's I have and the 3.08's I was thinking about. If that does not give me the reduction I am looking for then I may have to bite the bullet and come up with the money for the overdrive tranny and put the 3.92's back in. I found a site someone had listed on here for ring-pinion.com and they have the gears listed for around $135. (anybody ever bought from there before) Ol'ford nut, thanks for the tip on the O rings on the striker plate bolts. I plan to get some tomorrow and see if I can get the same luck!
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By SteveF100239 - 15 Years Ago
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I got the O rings yesterday and put them on the bolts between the plate and door frame. WOW! what a difference. Thanks for the tip, it worked like a charm.
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