Jump to content

Archived

This topic is now archived and is closed to further replies.

Farmall Doctor

Rear Axle Ratios

Recommended Posts

I'm looking for a rear axle with a bolt pattern wheel (not the cast spoke style) that has hydraulic brakes and a higher speed gear ratio. (2 ton or heavier) I found a mid 70's Ford 800 truck that has a 4 speed transmission behind a straight six engine which has a single speed rear axle. I have also found a mid 60's GMC tow truck which looks to be at least a 2 ton truck that has a 2 speed rear axle (vacuum shift). The rear axle is genuine GM with the numbers 3873551 cast into the pot.

Which one do you think will have the higher highway speed? When they build a 2 speed rear axle is it a lower ratio and higher one on the shift up, or a higher ratio with a shift down? .. or is it a happy medium in between? Hmmm.... I don't really need a 2 speed rear as I am likely going with a 13 speed Eaton overdrive transmission. (RTO 9513) behind my 6V53 Detroit engine. I am going for fuel mileage and highway speeds with this truck. This combination is going in a '91 Ford F-450. I can NOT afford to buy a diesel truck, so I am building one to the specs that I want, plus I really love the old Detroit engines. I got the truck for free and the engine cheap. I would appreciate any advice for what rear end to use. The ultimate transmission would be an Eaton 8LL but they are like gold, and I found this RTO13 for scrap price.

Thanks,

Darryn :blush:

Share this post


Link to post
Share on other sites

What are you planning to do with your truck?

A 6V-53 is an awfully large and heavy engine to be put into a pickup size truck.

It also isn't all that much more powerful than a Ford 460 V-8. In most automotive applications the 6V-53 was rated in the 180-210 HP range.

In order to utilize the power you are going to need all 13-speeds to get any use out of that 6V-53.

As far as gear ratios are concerned, they will change if you use pickup sized tires or 19.5" Lo-pro tires.

As to which one you will want to use, I would say neither. The one out of the Ford is most likely a high numerically ration due to the 6-cylinder engine. The one out of the GM is going to be a real headache regardless of the ratios.

Good luck.

Share this post


Link to post
Share on other sites
I'm looking for a rear axle with a bolt pattern wheel (not the cast spoke style) that has hydraulic brakes and a higher speed gear ratio. (2 ton or heavier) I found a mid 70's Ford 800 truck that has a 4 speed transmission behind a straight six engine which has a single speed rear axle. I have also found a mid 60's GMC tow truck which looks to be at least a 2 ton truck that has a 2 speed rear axle (vacuum shift). The rear axle is genuine GM with the numbers 3873551 cast into the pot.

Which one do you think will have the higher highway speed? When they build a 2 speed rear axle is it a lower ratio and higher one on the shift up, or a higher ratio with a shift down? .. or is it a happy medium in between? Hmmm.... I don't really need a 2 speed rear as I am likely going with a 13 speed Eaton overdrive transmission. (RTO 9513) behind my 6V53 Detroit engine. I am going for fuel mileage and highway speeds with this truck. This combination is going in a '91 Ford F-450. I can NOT afford to buy a diesel truck, so I am building one to the specs that I want, plus I really love the old Detroit engines. I got the truck for free and the engine cheap. I would appreciate any advice for what rear end to use. The ultimate transmission would be an Eaton 8LL but they are like gold, and I found this RTO13 for scrap price.

Thanks,

Darryn :blush:

Hi, most gas powered trucks had slow speed ratios as the gas engines had high rpm's.. A common one was the 650 to 1 ratio.However the 617 to 1 was a faster ratio for "cowboy" drivers.I haven't got my chart in front of me but a 9513 trans is about .75% overdrive in high gear.Your 6V53 will turn about 2500 rpms without hurting it.What size tires are you going with?Also if you go with juice brakes you will need to have a vacuum pump as diesels have NO vacuum.If you can get a look, the number of teeth on pinion and on crown gear will be stamped on the end of the pinion behind the U joint.Just divide lower number into higher number and that will tell you ratio.Post your tire size and I can tell you what your rpms/mph speed will be with 9513 trans.Hope this helps.Cooter

Share this post


Link to post
Share on other sites

Just count the turns that the pinion shaft turn to cause the wheels to turn one turn. Both wheels must move the same 1 turn. At 60 miles per hour, the wheels must travel 5280 ft in one minute. The distance around the wheels into 5280 gives you the Rpm on the axle. Them what ever the ratio is times the calculated Rpm of the wheels. You will not want to run your engine at full speed to achieve your cruising speed so use a lessor value. At 25% overdrive say 2100 times 1.25 That would put your pinion at 2625 rpm

I'm looking for a rear axle with a bolt pattern wheel (not the cast spoke style) that has hydraulic brakes and a higher speed gear ratio. (2 ton or heavier) I found a mid 70's Ford 800 truck that has a 4 speed transmission behind a straight six engine which has a single speed rear axle. I have also found a mid 60's GMC tow truck which looks to be at least a 2 ton truck that has a 2 speed rear axle (vacuum shift). The rear axle is genuine GM with the numbers 3873551 cast into the pot.

Which one do you think will have the higher highway speed? When they build a 2 speed rear axle is it a lower ratio and higher one on the shift up, or a higher ratio with a shift down? .. or is it a happy medium in between? Hmmm.... I don't really need a 2 speed rear as I am likely going with a 13 speed Eaton overdrive transmission. (RTO 9513) behind my 6V53 Detroit engine. I am going for fuel mileage and highway speeds with this truck. This combination is going in a '91 Ford F-450. I can NOT afford to buy a diesel truck, so I am building one to the specs that I want, plus I really love the old Detroit engines. I got the truck for free and the engine cheap. I would appreciate any advice for what rear end to use. The ultimate transmission would be an Eaton 8LL but they are like gold, and I found this RTO13 for scrap price.

Thanks,

Darryn :blush:

Hi, most gas powered trucks had slow speed ratios as the gas engines had high rpm's.. A common one was the 650 to 1 ratio.However the 617 to 1 was a faster ratio for "cowboy" drivers.I haven't got my chart in front of me but a 9513 trans is about .75% overdrive in high gear.Your 6V53 will turn about 2500 rpms without hurting it.What size tires are you going with?Also if you go with juice brakes you will need to have a vacuum pump as diesels have NO vacuum.If you can get a look, the number of teeth on pinion and on crown gear will be stamped on the end of the pinion behind the U joint.Just divide lower number into higher number and that will tell you ratio.Post your tire size and I can tell you what your rpms/mph speed will be with 9513 trans.Hope this helps.Cooter

Share this post


Link to post
Share on other sites

...OK. It will likely get mostly empty highway miles, and when it is hooked to a trailer it will be pulling 10 000lbs tops.

now.... Mark, the 6V53 is 38" long, 36" wide and 40" high.. not all that large. It weighs 1450 lbs...not much more than the powerstroke that it is replacing. My specs show them rated over 230 hp. It came out of a Ford Loisville, so I highly doubt that it has 180 hp.

I will be using normal sized tires for a super duty Ford, or those new low profile ones. A towing buddy of mine has a bunch of used ones.

What would be the headache of a 2 speed axle? They are still used today.

Cooter, thanks for the info. I did find some info on the 'net with transmission ratios.. I'll try and find it again. Yes I am using hydraulic brakes, and no, I don't need to worry about that because remember, diesel fords used hydraulic assist power brakes...fed off of the power steering pump. I will look to see if there are any stampings on the pinion housing next time.

What about a school bus rear? What kind of ratios do they normally have? Any other places to look for axles?

Darryn

Share this post


Link to post
Share on other sites

School buses have gear ratios all over the map. I have driven some that had max top speed of 47 MPH. I have driven some that still had a ways to go to hit the governor at 75 MPH. Your challenge in using a school bus rear end is finding a wet brake axle without spokes.

The challenge with the 2-speed and making it work is you indicated it had a vacuum shift. Since you already answered the question about a vacuum source the challenge won't be quite as daunting. The other challenge is GM doesn't support their older equipment as well as IHC and Ford. And now that GM is getting out of the medium duty truck business I am thinking parts and pieces are going to be getting even harder to find.

The 6V-53 should have a engine data plate on it somewhere that says what HP rating the engine has. I would be surprised if it is rated for more than 210 HP. Changing injectors can boost the HP but you are going to need a lot more cooling capacity to use it.

Which brings up another issue for you--cooling.

2-cycle DD's create a lot more waste heat than 4-cycle engines do. It is part of the reason why they use more fuel than comparable sized engines from the other engine manufacturers. The stock radiator in your Ford isn't going to be nearly big enough if you ever want to work your truck, particularly if you are going to go somewhere that is hot and has any grades.

Share this post


Link to post
Share on other sites

I am not concerned about whether anybody likes my project or my engine choice. My question was more about how to figure out what rear end I could find for a good ratio. I am not concerned about the engine, or the cooling, or vacuum source. I have machine shop equipment and know how to use it....I can adapt anything to anything.

I guess I'll just have to keep looking until I find a fast rear end.

Darryn

Share this post


Link to post
Share on other sites

Cooter, could you look to see if you have that spec sheet handy? I can't find that model of transmission specifically on the Eaton website. Thanks

Share this post


Link to post
Share on other sites
Cooter, could you look to see if you have that spec sheet handy? I can't find that model of transmission specifically on the Eaton website. Thanks

Found my Eaton slide chart.For the 13 speed models its only showing the RTO14613 & RTO15613 trans.Your RTO 9513 is a older model thats built for a less hp/torque engine.Over the years we've used them(RTO9513) on 400hp Cummins and had no problems, has a lot to do with the driver.That being said, it will more than stand what your going to do with it.My chart shows that the two 13speeds trans shown are .87 overdrive in high gear.I'm sure your 9513 will be the same as the ones above are built beefier to stand more torque/hp.My chart shows at 2000 rpms, with your trans and a 433 ratio and 11x22.5 tires you would be going 64 mph.My chart shows from 336 ratio thru to 557 ratio.I doubt if your tires will be as high as 11x22.5 so I would say you would want to have something around a 355 ratio.Your trans will have a 12.56 to 1 ratio in lowest gear, just so you know. Let me know if you need some other specs.Hope this helps.Cooter

Share this post


Link to post
Share on other sites

Thanks Cooter! That info is just what I need! I think I will do some more calling around and see if I can find a rear end out of a diesel truck... maybe a medium duty something-or-other. Maybe then I will find a fast one. Unless I can find some numbers on those other rear end that I found. ... I just hope I can find one C-H-E-A-P! If not, it will have to get a slower one until I can afford what I really want. Being broke just plain sucks!! haha :blush:

Darryn

Share this post


Link to post
Share on other sites

Darrryn when you are checking diff ratios, its a bit hard to get the 2 wheels turning togeather when you are on your own in the junk yard, easyer to turn one wheel only and devide by 2,

2 speeds are OK if you can find a fast one, on a Eaton diff you can fit a electric shift, with the roadranger tho I dont think you will need a 2 speed.

trucks/bus with a diesel + auto trans will have a fast diff

Jake

Share this post


Link to post
Share on other sites
...OK. It will likely get mostly empty highway miles, and when it is hooked to a trailer it will be pulling 10 000lbs tops.

now.... Mark, the 6V53 is 38" long, 36" wide and 40" high.. not all that large. It weighs 1450 lbs...not much more than the powerstroke that it is replacing. My specs show them rated over 230 hp. It came out of a Ford Loisville, so I highly doubt that it has 180 hp.

I will be using normal sized tires for a super duty Ford, or those new low profile ones. A towing buddy of mine has a bunch of used ones.

What would be the headache of a 2 speed axle? They are still used today.

Cooter, thanks for the info. I did find some info on the 'net with transmission ratios.. I'll try and find it again. Yes I am using hydraulic brakes, and no, I don't need to worry about that because remember, diesel fords used hydraulic assist power brakes...fed off of the power steering pump. I will look to see if there are any stampings on the pinion housing next time.

What about a school bus rear? What kind of ratios do they normally have? Any other places to look for axles?

Darryn

Actually, the "Wet" weight of a 7.3 PSD in a Ford pickup or cab/chassis was between 850 & 900#. And the ZF 5-speed was built with an alum. bell housing & transmission case so it was relatively light also. Ford recommended against putting heavy snow plows, etc on them. Putting 500# more engine and a heavy Road Ranger behind that engine even on an F-450 might bend or otherwise hurt some parts. The early PSD's, at least the 94-1/2 to '97's had a vaccum pump to run the brakes and a "Normal" vacuum booster on the master cylinder. I don't think it'd be that hard to get one of those vacuum pumps mounted to the 6V-53. They're actually smaller than a P/S pump. I don't think the hyd. brake boost started until '99 with the Super-Duties. Not sure what year F-450 You're dealing with but the 6.0 weighed about the same as the 7.3.

Also, the F-450 was normally geared numerically higher than the pickups, but I'd say there's a pretty good chance Your F-450 has 4.10 gears already, possibly 4.56's. Not sure about the F-450's but I think 3.55's were available on the F-350 C&C. I know they were on the SRW pickups.

Share this post


Link to post
Share on other sites

Hi, Dr Evil. I did have a look under the hood this weekend and it does have the hydraulic brake booster. It also has a Vacuum pump to run the heater and AC controls.. and you are right it is quite small. My truck is a '91. Where do you think I should beef it up? ... the frame, shock mounts, or front axle? That can easily be done, and might be a good idea anyhow. I went with this truck because of the solid front axle...and it was free. It has NO rear end, engine has a hole in the block, and my friend needs the transmission for a spare for his other trucks.

Jake, thanks for the thoughts.. that would be a good way to check the ratio... and more accurate at that.

I heard back from a local truck wrecker this afternoon who has a rear end from a propane tank delivery truck. He thinks it is at least a 2 ton, hydraulic disc brakes, and it had 19.5 " low profile wheels. The truck was a diesel with an automatic. He wasn't sure of the ratio, but figures it should be what I want. He offered it for $600..... if I can get him to throw the rims and tires in it might be a good deal for me. I won't give up yet though.. I'm still waiting on some more replies.

Thanks so far, everyone.

Darryn

Share this post


Link to post
Share on other sites

...Okay, just so you all don't think I'm totally NUTS and that it can't be done, here are a couple that I have found.

This one earns it's keep pushing snow.

This 6V53T powered Dodge Power Wagon is apparently pulling a trailer for a building/Renovation company.

..Oh, and just for fun,

Enjoy,

Darryn

Share this post


Link to post
Share on other sites

I am a confused by you going back and forth on the 800 and 450 - but if you are using the 450 rear and it has the bolt in frt. chuck it should be a dana - gm used the same chuck in the 60 and 70tys.

there also was some interchange between 3/4 and 1 ton - I used a rear end ( frt. chuck) from a much later one ton ford in a 3/4 ton chevy

so you should be able to get the ratio you want

Share this post


Link to post
Share on other sites
Some Dodges may have used the same center section also

You really to be looking at "pull your own parts" junk yards if they are available in your area, to save resources

They normally have autos and trucks to 1T. I did see a 2T chevy at one and some small school bus chassis.

I got a 3.55 ratio Dana 70, single rear wheel drum to drum for less than $100. US from a Dodge Cummins.

I expect the price of medium and heavy truck parts would go down if there was competition from the large operators.

We run a line-haul rig, the JY's see us coming when it comes to used parts.

I like you project. WE have an 88 F350 that I wanted to put a 6v53 and an RTX -9 in, ended up with overhauling the 460 gaser because all the experts said 6v53's didn't belong in F350's.

Good luck!!

Share this post


Link to post
Share on other sites
I am a confused by you going back and forth on the 800 and 450 - but if you are using the 450 rear and it has the bolt in frt. chuck it should be a dana - gm used the same chuck in the 60 and 70tys.

there also was some interchange between 3/4 and 1 ton - I used a rear end ( frt. chuck) from a much later one ton ford in a 3/4 ton chevy

so you should be able to get the ratio you want

I don't have any rear end at all...it's sitting on blocks, that's why I am looking for something completely different. I'm still waiting for some calls back.

Thanks

Darryn

Share this post


Link to post
Share on other sites

Farmall Doc----

You might wish to consult with "Mike Mc" over on the ACME site (Antique Caterpillar Machinery Enthusiasts). Mike Mc is from Bakersfield California and repowered and rebuilt a Dodge Power Wagon from the ground up---------he installed a 5.9 Cummins, plus changed out transmissions and rear end-----------and I believe reworked the front end to handle the load.

I am thinking he used a rear end out from under a Ford 1 ton-----------then he is using 19.5" in rims to work his speed up and engine rpms down. Mike would have a lot of knowledge from "experience" to offer you on your project-----he went through alot of trial and errors----------but really came out with a great truck in the end.

Most rear ends will have a tag or stamp on them (somewhere) indicating the ratio--------good luck.

(don't forget-------you are gonna need dual straight pipes on that Detroit!!!!) keep us posted.

Delta Dirt

Avon, Ms 38723

Share this post


Link to post
Share on other sites

Hi, Delta..thanks for the heads up..I'll have to head over there..I haven't been to ACMOC in quite some time.

Check out this site!!

http://www.onlineconversion.com/bigger_tires.htm

Punch in any combination in any order to get the answer you want!! (SPEED, rpm, RATIOS, ETC)

Someone over at 4BT Swaps.com set me on to that little site.

Thanks.

Darryn

Share this post


Link to post
Share on other sites

I once wanted to do a similar build up just to be different and cheap. I wanted a 1 or 2 ton with twin screw and a tilt bed, In looking around I was told that there was a Roadranger 10 speed built that was a good bit lighter than the 95013 speed as we know it today. I always liked to shift without a clutch and this was one of the reasons to build it into my own truck. Seems like Spicer built a light trans as well. I never found one but several older guys in the trucking business said that they were built. Was even told by one older gent that some of the cases were built of aluminum. Wondered if any of you all knew which trans this would be.

I had found a twin screw rear setup under a military C65 chevy that had the eaton 3 speed rears ((2) 2 speeds ahead of each other) and in a lighter version than the 34,000 lbs capacity we usually find. Just never put the combination together. Given the chance at those same parts today I would tackle it in a heartbeat!! Of course today it would need to have a front wheel drive axle as well.

ed

Share this post


Link to post
Share on other sites

Ed they built a rt6613 and i think a 10 speed too but in the 13 speed there was only 11 usable gears and im not 100% but i think there was a 15 speed that you only had 12 or 13 usable

hope this helps

matt

Share this post


Link to post
Share on other sites
Ed they built a rt6613 and i think a 10 speed too but in the 13 speed there was only 11 usable gears and im not 100% but i think there was a 15 speed that you only had 12 or 13 usable

hope this helps

matt

...RT...RTO 613.....bottom three deep reduction...next five split as per normal through range change etc...hence total of thirteen speeds. Standard equipment on the 70's line of IHC Australian trucks....Cummins 555 engines..both 4x2 and 6x4 models...Had several of these trucks from new...

Mike

Share this post


Link to post
Share on other sites

How much lighter were they?? Where they physically much smaller? and who built the lighter 5 speed? If a I was gonna use the three speed eaton rears there is really only a need for a five speed ahead of it anyway. I think a three speed rear would work pretty good behind an automatic actually. Never really heard anyone to talk about the lower speed ratios on them so I don't know how far apart they were. Think we had one with 4.11's in the high side. Do any of you guys have books on these by any chance?

I know lots of people did not like the three speed combo that went with having a pair of 2 speeds in tandem, but it sure worked good behind a detroit. I think they would be pretty slick in a HD pickup.

ed

On a different question what was the fuel milage like on the little 555 and what did that engine weigh? We don't see them in any thing here except some old Massey and versatile tractors. Don't think I ever saw one in a truck.

Share this post


Link to post
Share on other sites

...Ed..I assume you addressed the last post to me...???

..I am familiar with most North American terminology...although the "twin screw and the tilt bed "...part had my mind wandering back to something like "Rosies Cantina......."..and the soiled doves therein....but I digress..

...what I am certainly not familiar with is those "three speed eaton rears"...as my specific involvement with trucks started with British Bedford /Ford etc which had two speed Eaton tandems...then Australian trucks...then finally proper trucks....Mack from the USA...

..those rear end ratio's were more in the 6.5 mark...than the 4.11 you mentioned...but then again ..the Mack in the US of A , ran a nine speed box....in New Zealand they were mostly 12 speeds...then later 18 speeds...so I guess the trucks were speced to suit the terrain....

Back to the IH Australian trucks....The first ones had either V392...or 555 Cummins....Because the petrol V 392 ran about 3400 rpm tops....the early triple 5's were run at that speed....they shook the alternator brackets off at first...then the starter motor would fall off...then the big one..the water pump /fan assembly would decide to head off from the engine and destroy the radiator....that was 'game...set and match" for most outfits running those engines...however, the later ones only ran at 2400/2500 rpm....no troubles at all...can't remember the feul consumption but they went very well...light over the front axle so as I had multiple forestry gravelling contracts...they were ideal...and we had two with MT650 auto's which would out perform the venerable Mercedes 6x4's traction wise...The others had that RT..or RTO 613 Road ranger trans..which was ideally suited to that engine...physically a lot smaller than the 12 and 15 hundred torque rated tran's.

International Harvester, New Zealand , were an excellent company to deal with...and apart from that piece of crap ...the dreaded 358 Nuess engined 1800 series truck...we had few issues with the Australian product.....Even had a DV550 engined 6x4 ...

As a matter of mild interest...a local cocky ..(farmer) ..down the road a mile or so from me...still runs one of the 4x2 Cummins powered IH truck that I brought new..in 1975....Sure..it is only on farm type work...but it still runs just fine...

Mike

post-157-1262509785_thumb.jpg

Share this post


Link to post
Share on other sites

×
×
  • Create New...