Re-gearing help
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Elder User
Joined: Jul 2011
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From: Vernon, BC
Re-gearing help
I'm going to re-gear my '94 4x4. Currently it has 3.55 LS. Can I re-gear by just replacing the ring and pinion? I know one can purchase a whole kit but they are $350 or more on Rock Auto and with a 4X4 I'm looking at $700 or higher just for the parts. I want to keep the costs as low as possible.
I don't have access to a shop anymore so I will purchase the parts and have a mechanic do the work. Therefore the wreckers are not an option.
I don't have access to a shop anymore so I will purchase the parts and have a mechanic do the work. Therefore the wreckers are not an option.
Senior User
Joined: Apr 2010
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The minimum you will need is a new pinion seal, shim kits for the pinion and carier on both axles, and crush sleaves if your axles uses them. does the shop you are having do the install have a pinion bearing puller? If not you should get new pinion and carrier bearings and races, because it is imposable to remove the bearings without destroying them
I would replace all the bearings if possible. when i tore into my truck to install a locker i found one of the carrier bearings was badly pitted that truck only had 90000 at the time
I would replace all the bearings if possible. when i tore into my truck to install a locker i found one of the carrier bearings was badly pitted that truck only had 90000 at the time
Tuned
Joined: Jan 2008
Posts: 281
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From: Virginia
I'm sure you probably could, but while you're in there why not replace the bearings and seals? Preventive maintenance. Plus depending on your trucks mileage, the parts are most likely worn and could use freshening up.
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Elder User
Joined: Jul 2011
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From: Vernon, BC
Thank you 97puller and Big_Red_Brute for your replies. Based on your information I can replace the ring and pinion gears in order to re-gear my truck. I appreciate the note about the bearings and seals, shims and crush sleeves. I never thought of that. Replacing the bearings and races is also a good idea as my truck has about 188,000 Kms on it, so it's well over 100,000 miles.
Is there a way to tell if my truck uses 30 or 31 spline axles? Both are available in the Rock Auto Parts Catalogue.
Is there a way to tell if my truck uses 30 or 31 spline axles? Both are available in the Rock Auto Parts Catalogue.
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Joined: Apr 2010
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I recommend Randy's Ring and pinion for all your differential parts if you call them and tell them the make and model they will set you up with every thing you need.
Another thing to keep in mind is some differentials have have a "carrier split" for example the Dana 60 in my truck has two different carriers one for 4.10:1 and higher gears and a different one for gears lower than 4.10:1.
Also make sure the shop that is doing the work has experience with differentials. There aren't very many that have the right equipment and know how to set up differentials.
Another thing to keep in mind is some differentials have have a "carrier split" for example the Dana 60 in my truck has two different carriers one for 4.10:1 and higher gears and a different one for gears lower than 4.10:1.
Also make sure the shop that is doing the work has experience with differentials. There aren't very many that have the right equipment and know how to set up differentials.
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Joined: Apr 2010
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I was bored so I did some research, the dana 44 front in the F150 has a carrier split at 3.73, so if you want a lower gear than 3.73:1 you will need a new carrier for the front.
The 8.8 rear in F150's are 31 spline, no carrier split on them.
The 8.8 rear in F150's are 31 spline, no carrier split on them.
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Elder User
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From: Vernon, BC
97puller, Thank you once again. I don't know how you look that stuff up but I sure appreciate it. I'm going to talk to the shop this week about whether they want to do the job and if they are properly equipped. I want to re-gear to 3.73 so I won't have to be concerned about the "carrier split." I presume that if the rear axle is a 31 spline the front axle is also a 31 spline?
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Elder User
Joined: Jul 2011
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From: Vernon, BC
Evan_P, I thought of simply exchanging my differentials but I only need 3.73 gearing. I think 4.10 would be too low. I don't need that kind of power and I don't want to be revving the engine so high at highway speeds. I have only changed from the stock 15" tires to 16's and they are only 31" tall. The truck performs OK on the level highway but when loaded it is lacking some power.
Cargo Master
Joined: Apr 2003
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From: Parkesburg PA
I went from 3.55's to 3.73's in my 05 Mustang GT and it's a very subtle change. I like it but I had lunched the 3.55's so I was on the hook for gears anyway...
What size tires do you have or do you plan on running? If your stock tires are 235/75-15's and you replace them with 31's, IIRC going to 4.10's restores the same effective ratio as the 235's with the 3.55 gears. In other words I don't think it'll be too low.
As for the carrier, yes there is a split. What I did was get an empty open carrier and reused the spider gears. Yukon gear has one that's like $90. The shop I used charged $700 labor for both axles and with gears, bearings, locker for the rear, etc it was around $1,800 when I did my one Bronco. I went with 4.10's and was very happy with them.
Your rear axle should be a 31 spline. The cars used 28 and supposedly some of the truck rears did too, but my 86 has 31 spline axles. It just has a 3/4" cross pin vs a 7/8" pin from what I recall.
What size tires do you have or do you plan on running? If your stock tires are 235/75-15's and you replace them with 31's, IIRC going to 4.10's restores the same effective ratio as the 235's with the 3.55 gears. In other words I don't think it'll be too low.
As for the carrier, yes there is a split. What I did was get an empty open carrier and reused the spider gears. Yukon gear has one that's like $90. The shop I used charged $700 labor for both axles and with gears, bearings, locker for the rear, etc it was around $1,800 when I did my one Bronco. I went with 4.10's and was very happy with them.
Your rear axle should be a 31 spline. The cars used 28 and supposedly some of the truck rears did too, but my 86 has 31 spline axles. It just has a 3/4" cross pin vs a 7/8" pin from what I recall.
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Elder User
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From: Vernon, BC
F100beatertruck, I am now running 235/85 R 16. They work out to 31" so I think they are only 2" larger diameter. However I now live on a ski hill and my truck definitely feels underpowered going home. I thought the 3.73 gears would restore the stock ratio as I only went up in tire size a small amount.
How does one figure out what gears they need to return to stock ratios? I'll go 4.10 if necessary but don't want to lose what gas mileage I do get. I've looked for re-gearing information but I get many posts of what seems to be unrelated stuff. Computers are not my forte
How does one figure out what gears they need to return to stock ratios? I'll go 4.10 if necessary but don't want to lose what gas mileage I do get. I've looked for re-gearing information but I get many posts of what seems to be unrelated stuff. Computers are not my forte
Lead Driver
Joined: Feb 2013
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From: Roseville, MN
According to the BF Goodrich site, an LT235/85R16 All-Terrain KO is 33" OD. An LT235/75R15 (stock size on a '94 half ton?) is 29". So to get the same effective ratio with the larger tires you need 3.55 x 33 / 29 = 4.04 gears (if those aren't the correct before and after tire diameters plug the right numbers into a calculator).
I made that tire change on my '95 F-150, also with 3.55 gears (351W, E4OD). It was a little doggy starting on hills, and I got used to shifting out of overdrive any time I was running 55 mph with any hills or curves. But I decided it was well worth putting up with vs. the alternatives of paying about $1000 per axle to get them regeared (as jumbofordman said, labor will run you more than the parts) or searching for axles to swap in. Whether it's worth it to you is obviously up to you. But it wasn't to me. I put about 100,000 miles on the truck like that, including hauling my camper while towing my Jeep in Colorado.
I made that tire change on my '95 F-150, also with 3.55 gears (351W, E4OD). It was a little doggy starting on hills, and I got used to shifting out of overdrive any time I was running 55 mph with any hills or curves. But I decided it was well worth putting up with vs. the alternatives of paying about $1000 per axle to get them regeared (as jumbofordman said, labor will run you more than the parts) or searching for axles to swap in. Whether it's worth it to you is obviously up to you. But it wasn't to me. I put about 100,000 miles on the truck like that, including hauling my camper while towing my Jeep in Colorado.
Senior User
Joined: Apr 2010
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97puller, Thank you once again. I don't know how you look that stuff up but I sure appreciate it. I'm going to talk to the shop this week about whether they want to do the job and if they are properly equipped. I want to re-gear to 3.73 so I won't have to be concerned about the "carrier split." I presume that if the rear axle is a 31 spline the front axle is also a 31 spline?
I did some looking here: Diff Wizard
I also have a differentials manual from randys ring and pinion, I highly recommend it.