View Full Version : 727 low gear set
08-24-2004, 10:24 PM
what are your thoughts on the low gear set for the 727? what do they cost and is it worth it? is it better for towing or does the lower 2nd leave too big a gap between it and 3rd? im getting a good deal on a tranny rebuild so i may be able to swing for them. and since i bought a 20' boat, the IH is primarily a tow rig now so i need tyo know the best route here. the rig BTW is a 69 3/4t 392 with 4.11 gears. thanks-ryan
08-25-2004, 01:11 AM
I researched this issue a while back.
There's talk that some dump trucks had a 727 with the low gear sets. Something like a 3.5:1 first. I believe the 2nd and 3rd gears are the same though. I even know a guy that has this setup in his CJ7 with 42's. The low first causes it to "whine" when in first gear.
The problem with the dump truck gears is that there are only a handfull left in existence - I can't confirm that though.
I believe there's a company that sells the low gears you've mentioned, but they want an enourmous price for them. Seems like they want about 700 or so - too rich for my blood.
My advice would be to leave your 727 alone and maybe get some lower axle gears - unless you have tons of $$$ to spend.
08-25-2004, 04:32 AM
i saw a set in a jeg's catolog last week and there going for around $400
08-25-2004, 05:06 PM
Rumor is that they don't even exist. From what I understand there is a slightly different gear set but the ratio is the same.
08-25-2004, 05:21 PM
I think A&A Transmission sells a lower gear set for 727. From what I remember the set is 2.7:1 where as a normal IH 727 set is 2.45:1. In gear driven terms it isn't that much, but in auto it is substantial difference, from what I hear. Remeber that .25 is multiplied by your axle gears. PM Colin Rush, I think he has a set is was looking to get rid of, or he can point you in the correct direction to find them.
2.77 set for 405.00:
08-25-2004, 08:01 PM
Yes' Sir they do exist. I have a set in my 727 that I bought through A&A transmissions and had installed by D&C during my tranny buildup. I forget the exact ratios... something like 2.56???? in 1st, I can't remember. You can call them @ (317) 831-3066. I found that they produce them and also supply Art Carr who sells them at a incredible markup. I have no problems with them whatsoever, no gear whine, not to wide a gap between gears.... I like them. I think thay are a better deal than axel gears if you have your tranny apart already. Just my .02 -wingnut13
08-26-2004, 02:23 AM
I have been running a low gearset in my '76 Scout's 727 for a number of years now. I really like it, and think it was worth the $395 (plus shipping) I spent. I got the set from JVX, Inc. of Memphis, TN. They are Torqueflite specialists with quite a bit of experience. The 1st gear ratio is 2.74:1. The 2.77:1 is recommended for race vehicles only, as the cut of the gears makes them noisy (per JVX). The second gear is slightly lower than stock. The planetary set also comes with a nice Torrington thrust bearing to replace the stock thrust washer.
My 304-powered Scout is used to tow my 2500+ lb sailboat/trailer. I feel that the low gearset is an advantage when towing at slow speeds up steep roads. My Scout also has a Dana 300 transfer case. This, coupled with the low A/T gearset, makes for a nice 1st gear/4L crawling ability.
08-26-2004, 07:18 AM
My old '67 Chrysler came with a factory trailer package - has what MoPar called back then a "police transmission" which has the lower 1st gear (along with a factory tranny cooler & a whopping 1qt extra capacity pan!!!) Gads!!!! So the factory parts are out there - somewhere!!!
Can you use a gear set out of a 904 in the 727 transmission??
The 904 comes with a 2.74 first and 1.54 second gear.
Also found where somebody said you could use a 12 torque converter in the 727 to get an effective lower stall speed, with out using a custom converter.. Does anybody have info releated to this.
07-01-2005, 03:25 PM
I have a 727 auto with a low gear (taxi) set.
I have made a sd33t 1980 traveler with an unoffered automatic trany option.
the sd33 has allways been slow off the line and the 1977 diesel automatics were DOGS!
Well , with a low gear set and adjustments to the kick down these known problems cease to exist !
The bigest problem is the sd33T makes a lot off extra HEAT because of the torque converter slipage.
I run a larger than stock oil pan on the 727 and an addtional transmision cooler in the grill after the cooler in the radiator, which is 4 core. So a lot of cold water goes on the head too. The EGT's run higher to so I have an intercooler and get my air from outside the hood.
The diesel winds up real quick with the low 1st gear and gets away from the stop signs really well.2nd is lower also and picks up around 15-20 MPH untill about 45 then 3rd kicks in.
At this time the RPMs are up good and the turbo sd33 just takes off. My top speed is 80-85 and will over heat the engine ; I can cruse 70-75 but watch it some on really long hills.
If I set the cruse control at 65 I can go all day long with out watching the EGT's no mater what the road does.
Needless to say night time driving is noticably better.
WE also use the low gear set in automatic OFF ROAD trucks --- the lower 1st is very noticeable in low 4x4.
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