raybing Posted July 1, 2007 Share Posted July 1, 2007 I have a 98 RD 600 withan EM7, t2080 (40% OD) that will only go 55mph. I was told it had 5.55 rears, maybe not true? Being a glider kit , how do I find the ratio? Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/ Share on other sites More sharing options...
Maxville Truck Posted July 1, 2007 Share Posted July 1, 2007 Raybing,crawl under the truck with some brake cleaner and a brush...., facing the rear of the truck on the front side of the rearend to the left of center is what I call a "ramp" clean that flat spot and start looking for the 3 number stamped into it. I have 6.34 ratio in most of my manure trucks and one with the 5.55, they all go at least 65 the 5.55 will push 70 at about 2150 to 2200 rpms..... But I had the rpms turned up on all the pumps. I know in the other posts somebody said that you could just turn the throttle stop screw to raise the RPMs that isn't totally true it will not give you enough fuel for any power... You may be able to see 2050 rpm but as soon as you put a load on it, you wont get any lug power until 1700 to 1800. I will warn you that your engine with different governor springs may freely rev as high as 2350... I told my pump guy I want full fuel under load at 2150. Good luck!! Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12824 Share on other sites More sharing options...
raybing Posted July 1, 2007 Author Share Posted July 1, 2007 Raybing,crawl under the truck with some brake cleaner and a brush...., facing the rear of the truck on the front side of the rearend to the left of center is what I call a "ramp" clean that flat spot and start looking for the 3 number stamped into it. I have 6.34 ratio in most of my manure trucks and one with the 5.55, they all go at least 65 the 5.55 will push 70 at about 2150 to 2200 rpms..... But I had the rpms turned up on all the pumps. I know in the other posts somebody said that you could just turn the throttle stop screw to raise the RPMs that isn't totally true it will not give you enough fuel for any power... You may be able to see 2050 rpm but as soon as you put a load on it, you wont get any lug power until 1700 to 1800. I will warn you that your engine with different governor springs may freely rev as high as 2350... I told my pump guy I want full fuel under load at 2150. Good luck!! Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12826 Share on other sites More sharing options...
raybing Posted July 1, 2007 Author Share Posted July 1, 2007 Ok Maxville, On the ramp face ; 5374P16 93 5B1665 Help? Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12827 Share on other sites More sharing options...
Maxville Truck Posted July 2, 2007 Share Posted July 2, 2007 Ok Maxville, On the ramp face ; 5374P16 93 5B1665 Help?That rearend is a little newer than any of my stuff (all 89 to 91)... their numbers are all stamped with a standard looking letter. the ratio that I have seen on a 97 MR (1 of 3) that I built for a neighbor was stamped almost as if they used a sharp center punch and formed the numbers digitally, and were not real easy to see, but if you read the other numbers just keep looking around that area, anyways i think those numbers you gave me here are just the part numbers of the carrier, (someone correct me If I'm wrong) look for just a 3 digit number ussually towards the right middle of that "ramp" sometimes it says ratio close to the number. but between the 1st and 2nd of the 3 numbers their should be a decimal point. that will be the ratio. My trucks with 6.34 and t2060 trans will do clse to 65-70 (cranking probable over 2250 rpm though) I had one e-6 4valve once slowly lose rpm over time I think the govenor spring keeper (inside the pump was slowly backing off) just call me crazy though... Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12828 Share on other sites More sharing options...
Maxville Truck Posted July 2, 2007 Share Posted July 2, 2007 raybing found a picture of the "ramp" on ebay clearly showing a ratio Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12830 Share on other sites More sharing options...
raybing Posted July 2, 2007 Author Share Posted July 2, 2007 That rearend is a little newer than any of my stuff (all 89 to 91)... their numbers are all stamped with a standard looking letter. the ratio that I have seen on a 97 MR (1 of 3) that I built for a neighbor was stamped almost as if they used a sharp center punch and formed the numbers digitally, and were not real easy to see, but if you read the other numbers just keep looking around that area, anyways i think those numbers you gave me here are just the part numbers of the carrier, (someone correct me If I'm wrong) look for just a 3 digit number ussually towards the right middle of that "ramp" sometimes it says ratio close to the number. but between the 1st and 2nd of the 3 numbers their should be a decimal point. that will be the ratio. My trucks with 6.34 and t2060 trans will do clse to 65-70 (cranking probable over 2250 rpm though) I had one e-6 4valve once slowly lose rpm over time I think the govenor spring keeper (inside the pump was slowly backing off) just call me crazy though... Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12832 Share on other sites More sharing options...
raybing Posted July 2, 2007 Author Share Posted July 2, 2007 Ok Maxville, On the ramp face ; 5374P16 93 5B1665 Help?Hey Maxville. I will look closer tomorrow. Nice MR's you built. MR would work great for a tree spade truck, lower cab height and easier to enter and exit cab. My dream would include a 6 speed allison. New truck way too much money and all the MR's I saw were worn out garbage trucks. I shift a lot off road backing up to the tree so an auto would be ideal. By the way I have had my pump turned all the way up on the dyno. But not taken off and adjusted for RPM"s. Thanks for the info. Ray Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12833 Share on other sites More sharing options...
Maxville Truck Posted July 2, 2007 Share Posted July 2, 2007 I think an MR or an LE would suit you well. I have the ins with a few people and ussually get them for around $10,000 almost always allison 740s (4 speeds). ussually come with big hydraulic pumps crankshaft driven. I'll attatch a before picture of the last one i did. (spent alot of money on body work etc.) I also put a former postal CH together as a TMR truck (also auto 740), That truck turned out good too!! Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12835 Share on other sites More sharing options...
raybing Posted July 2, 2007 Author Share Posted July 2, 2007 I think an MR or an LE would suit you well. I have the ins with a few people and ussually get them for around $10,000 almost always allison 740s (4 speeds). ussually come with big hydraulic pumps crankshaft driven. I'll attatch a before picture of the last one i did. (spent alot of money on body work etc.) I also put a former postal CH together as a TMR truck (also auto 740), That truck turned out good too!!OK I found the ratio 7.00!!!!!!!!!!!!! No wonder it is slow. Quote Link to comment https://www.bigmacktrucks.com/topic/2626-rear-end-ratio/#findComment-12837 Share on other sites More sharing options...
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