ComancheBSJ90 Posted March 1, 2009 Share Posted March 1, 2009 I have a 1989 Comanche 4.0L 5 speed, and wanted to buy Detroit TrueTracs for front and rear, but I need to know the gearing to buy the right model. I did search but 125 posts to read through made me give up, I do remember seeing it here somewhere. Numbers for the read diff: Dana 115.1 1l032C Dana CG42828 P8L523 43 14 Front: Dana 122.1 Are they on that rusty pumpkin plate or that disintegrating metal tag? If I had a location I may be able to scrap of enough rust to read. Thanks Link to comment Share on other sites More sharing options...
87Warrior Posted March 1, 2009 Share Posted March 1, 2009 The tags are located on a metal plate, usually vertical, on the left side of the diff cover. It is held on by two of the diff cover bolts. Sounds like your truck could use a fluid change anyhow. Do this and you can clean all the stamped metal up :brows: Link to comment Share on other sites More sharing options...
SuperWade2 Posted March 1, 2009 Share Posted March 1, 2009 I have a 1989 Comanche 4.0L 5 speed, and wanted to buy Detroit TrueTracs for front and rear, but I need to know the gearing to buy the right model. I did search but 125 posts to read through made me give up, I do remember seeing it here somewhere. Numbers for the read diff: Dana 115.1 1l032C Dana CG42828 P8L523 43 14 Front: Dana 122.1 Are they on that rusty pumpkin plate or that disintegrating metal tag? If I had a location I may be able to scrap of enough rust to read. Thanks 3.07's... the "43 and 14"... 43 / 14 = 3.07... I think it's 43 teeth on the ring and 14 on the pinion.... http://www.jeepforum.com/wiki/index.php/MJ_Comanche 3.07 - used with 4.0L I-6 engine / manual transmission. 3.31 - used with the rare "Fuel saver" package in '86. 3.55 - used with 4.0L I-6 engine / automatic transmission and with the 2.5L I-4 / 4 speed manual. 4.10 - used with 2.5L I-4 engine usually with 5 speed, also came with '86 Metric Ton models. 4.56 - rare but can be found on some older (~ '89 ~) models with 2.5L I-4 engine and auto transmission Link to comment Share on other sites More sharing options...
Comanche County Posted March 1, 2009 Share Posted March 1, 2009 Yep, my 89' with a 4.0L and AX-15 5 Speed came with 3.07s front and rear. Link to comment Share on other sites More sharing options...
ComancheBSJ90 Posted March 1, 2009 Author Share Posted March 1, 2009 Yes that is right I have 3.07 / 3.08 gears. Now I wonder if its worth it to get TrueTracs with this gear ratio or up the gears and only get a TrueTrac in the rear. Or use four Low off road and get the truetracs!! Options, Options! What gears would be good all around for light 4x4 ing and daily driver. With the ones I have I notice that when in the deep snow I can't get it started in 4hi unless I'm a little hard on the clutch so now I just automatically shift to 4lo. yes, I did verify the gears with the tags, and I changed my gear oil last week, but was not thinking of this modification. Thanks for the Information, Link to comment Share on other sites More sharing options...
SuperWade2 Posted March 1, 2009 Share Posted March 1, 2009 What size of tires you run, or planning on running? Link to comment Share on other sites More sharing options...
Eagle Posted March 2, 2009 Share Posted March 2, 2009 3.07s are a bad ratio even with stock tires. 3.54 isn't terrible, and 3.73 is quite acceptable with both stock tires and 30s. I ran 3.73s with 31x10.50s and I wished I had 4.10s -- only reason I ran that combo was that I had already bought the gears to go with 30" tires, then bought the MJ with a lift and 31s (and 3.07s -- UGH!), so I put in the gears I had. 3.07s are too ugly to even be good paperweights. Link to comment Share on other sites More sharing options...
mvusse Posted March 2, 2009 Share Posted March 2, 2009 I have 3.07's in my 94 XJ. Plenty of low end to light up the tires, plenty of high end to do 85 on the freeway with lots of pedal left. Unless I skip gears I go through 3 gears just to go from stand still to 15mph in the alleys. Cruise 25-30 in 4th, 35-40 in 5th, yet 3rd gear is tall enough to get up to 70 fast to merge into traffic. Shorter gears might be good with larger tires, but 3.07 is plenty with stock(ish). Link to comment Share on other sites More sharing options...
ComancheBSJ90 Posted March 3, 2009 Author Share Posted March 3, 2009 I have 3.07's in my 94 XJ. Plenty of low end to light up the tires, plenty of high end to do 85 on the freeway with lots of pedal left. Unless I skip gears I go through 3 gears just to go from stand still to 15mph in the alleys. Cruise 25-30 in 4th, 35-40 in 5th, yet 3rd gear is tall enough to get up to 70 fast to merge into traffic. Shorter gears might be good with larger tires, but 3.07 is plenty with stock(ish). I have stock rims/tires if anything I might upgrade to 16" rims, but that's a long shot. It must be that HO motor you have in your 94. My shift points don't come close to yours. Now I need to see my RPM values if I were to drive like you.... test drive.... If I were to drive: 15mph in 3rd rpm 600 25-30 in 4th rpm 800-1200 35-40 in 5th rpm 800-1200 It may be do-able but in 3rd gear the engine would be lugging! Normally I drive: 1 gear to 12.5mph @ 2000rpm 2 gear to 25mph @ 2000rpm 3 gear to 38mph @ 2000rpm 4 gear to 50mph @ 2000rpm 5 gear to 62+mph @ 2000rpm Are you driving like that to save gas? Link to comment Share on other sites More sharing options...
Pete M Posted March 3, 2009 Share Posted March 3, 2009 Shorter gears might be good with larger tires, but 3.07 is plenty with stock(ish). Yeah, but who want little donuts on their Jeep? Just 30" tires took all the wind out of my 88. 3.54 gears brought it all back (and possibly more). :D Link to comment Share on other sites More sharing options...
mvusse Posted March 3, 2009 Share Posted March 3, 2009 I have 3.07's in my 94 XJ. Plenty of low end to light up the tires, plenty of high end to do 85 on the freeway with lots of pedal left. Unless I skip gears I go through 3 gears just to go from stand still to 15mph in the alleys. Cruise 25-30 in 4th, 35-40 in 5th, yet 3rd gear is tall enough to get up to 70 fast to merge into traffic. Shorter gears might be good with larger tires, but 3.07 is plenty with stock(ish). I have stock rims/tires if anything I might upgrade to 16" rims, but that's a long shot. It must be that HO motor you have in your 94. My shift points don't come close to yours. Now I need to see my RPM values if I were to drive like you.... test drive.... If I were to drive: 15mph in 3rd rpm 600 25-30 in 4th rpm 800-1200 35-40 in 5th rpm 800-1200 It may be do-able but in 3rd gear the engine would be lugging! Normally I drive: 1 gear to 12.5mph @ 2000rpm 2 gear to 25mph @ 2000rpm 3 gear to 38mph @ 2000rpm 4 gear to 50mph @ 2000rpm 5 gear to 62+mph @ 2000rpm Are you driving like that to save gas? My shift light comes on around 15, 25, 35, 50. But hey, I'm getting 17mpg around town. Once you're up to speed it doesn't take a lot of torque to maintain it. Link to comment Share on other sites More sharing options...
Eagle Posted March 3, 2009 Share Posted March 3, 2009 My shift light comes on around 15, 25, 35, 50. But hey, I'm getting 17mpg around town. Once you're up to speed it doesn't take a lot of torque to maintain it. Heh, heh. Tell that to the guys trying to pull upgrades on the Interstate with a 4-cylinder 5-speed ... Link to comment Share on other sites More sharing options...
mrsinister Posted March 9, 2010 Share Posted March 9, 2010 Anyone have any info on what the standard ratio was for the 86' 2.8L with the automatic? Link to comment Share on other sites More sharing options...
Pete M Posted March 9, 2010 Share Posted March 9, 2010 86 is pretty much a "look and see" model year. the 87+ rules of thumb don't seem to apply anymore. :( Link to comment Share on other sites More sharing options...
Backroads Posted March 9, 2010 Share Posted March 9, 2010 86 is pretty much a "look and see" model year. the 87+ rules of thumb don't seem to apply anymore. :( found that out with mine! 2.5L with 3.55's Link to comment Share on other sites More sharing options...
Geonovast Posted March 9, 2010 Share Posted March 9, 2010 86 is pretty much a "look and see" model year. the 87+ rules of thumb don't seem to apply anymore. :( found that out with mine! 2.5L with 3.55's Chances are pretty good yours started out life with an AX-4. Link to comment Share on other sites More sharing options...
1986Comanche Posted March 9, 2010 Share Posted March 9, 2010 found that out with mine! 2.5L with 3.55's 3.54 is one of the gear ratios available in 1986 with the 2.5L. My 1986 with the 2.5L has 3.54s. Link to comment Share on other sites More sharing options...
1986Comanche Posted March 9, 2010 Share Posted March 9, 2010 Anyone have any info on what the standard ratio was for the 86' 2.8L with the automatic? My 1986 Jeep Comanche factory workshop manual shows two gear ratios available for the 2.8L V6 with an automatic. 3.54 or 4.10. I would bet that it has one of these two. Probably has 3.54s. Link to comment Share on other sites More sharing options...
jimoshel Posted March 10, 2010 Share Posted March 10, 2010 My shift light comes on around 15, 25, 35, 50. But hey, I'm getting 17mpg around town. Once you're up to speed it doesn't take a lot of torque to maintain it. Heh, heh. Tell that to the guys trying to pull upgrades on the Interstate with a 4-cylinder 5-speed ... You got that right. I hooked a 1500lb stock trailer up to my '89 MJ, 2.5 With 5 speed, loaded 2 horses ,2800 lbs, and went up Raton pass at 70MPH after I shifted down from 5th to 4th. Just wouldn't quit knocking in 5th. Good thing there's holes in the floor of the trailer tho. Lousy brakes and the horses had to drag their feet, Hooves? going down the other side. :rotf: Link to comment Share on other sites More sharing options...
mrsinister Posted March 10, 2010 Share Posted March 10, 2010 the dealers invoice says 4.10 but i was just curious what a standard was, thanks for the detailed answer Link to comment Share on other sites More sharing options...
MJ is dead Posted March 10, 2010 Share Posted March 10, 2010 Might have the paperwork somewhere. But what do ya think is standard with an 87 4.0 auto? 35 rear Link to comment Share on other sites More sharing options...
MancheKid86 Posted March 10, 2010 Share Posted March 10, 2010 i just checked mine, from what i can see from my tag, i have the rare 3.31 gearing for my 86, the tag is pretty worn down so just to makesure I'm going to clean it up for a better look. edits, the more numbers i uncover to more its looking like its not XD can't make out antidisestablishmentarianism it is yet, but ittl get there Link to comment Share on other sites More sharing options...
Pete M Posted March 10, 2010 Share Posted March 10, 2010 Might have the paperwork somewhere. But what do ya think is standard with an 87 4.0 auto? 35 rear 4.0 + auto = 3.55 gears 4.0 + stick = 3.07 gears 2.5L + 4spd stick = 3.55 gears (usually) 2.5L + 5spd stick = 4.10 gears (usually) Link to comment Share on other sites More sharing options...
jimoshel Posted March 10, 2010 Share Posted March 10, 2010 Don't know if it's standard but my '87 4WD with 4.0 and AW4 has a dana 44 with 3.07. Link to comment Share on other sites More sharing options...
mjeff87 Posted March 10, 2010 Share Posted March 10, 2010 i just checked mine,from what i can see from my tag, i have the rare 3.31 gearing for my 86, the tag is pretty worn down so just to makesure I'm going to clean it up for a better look. The uber-rare economy/fuel miser package.......I've yet to see one of those setups live and in person. About as rare as the stock 4.56 pacakge, which I've seen several of (and am running a stock D30/4.56 from one of in my MJ currently ;) ) Jeff Link to comment Share on other sites More sharing options...
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