JR67 Posted April 21, 2014 Share Posted April 21, 2014 (edited) Hello everyone, Who knows what Toyota has a 7.5 inch diff with the 4.56 or 4.88 ratio ? So far I have not been successful in finding this info, perhaps there are none with the short ratio, only the longer ones like in the Toyota Corona? I have a 18' Canadian TravLMate with an F292 axle which is the 4.10 ratio. Any info is really appreciated! Edited April 21, 2014 by JR67 Quote Link to comment Share on other sites More sharing options...
linda s Posted April 21, 2014 Share Posted April 21, 2014 On www.car-part.com I went through every year and no higher gears like your looking for. Best bet is after market ring and pinion like these http://www.ebay.com/sch/i.html?_odkw=toyota+ring+and+pinion+7.5+differentisal&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xtoyota+ring+and+pinion+7.5+differential&_nkw=toyota+ring+and+pinion+7.5+differential&_sacat=0 Linda S Gears always mess me up. Higher number lower gears. Lots of 4.56 here Quote Link to comment Share on other sites More sharing options...
JR67 Posted April 21, 2014 Author Share Posted April 21, 2014 Thanks Linda, I'll look into those gears on Ebay. For now I will start with going back to 14" rims and 3" smaller diameter tires and see what the difference is, I have 15" 235/75 LT tires now that make it hard to get going in first and basically render my 4th gear useless.... Cheers, Jurgen Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 21, 2014 Share Posted April 21, 2014 Going away from 235/75R15 will change your gearing ~13%. Going from 4.10:1 to 4.56:1 about 10%. 4.88:1 about 19%. Quote Link to comment Share on other sites More sharing options...
linda s Posted April 21, 2014 Share Posted April 21, 2014 I'm coming up with 11% difference on the tires alone. Almost the same as the gearing but of course I could be wrong. I'd go with new gears unless I already had good 14 inch tires and wheels that I could just use in the meantime. Wouldn't want to spend money on new ones. Your up In BC and I bet you take a lot of not so good roads in your travels. 15 inch tires and wheels handle ruts and rough roads much better and give you a little more clearance. Linda S Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2014 Share Posted April 22, 2014 Just understand that buying a R&P off Ebay is just the beginning. You'll have to find someone who has the skill to properly install them. It's not a simple, bolt-in operation. Quote Link to comment Share on other sites More sharing options...
linda s Posted April 22, 2014 Share Posted April 22, 2014 I think that guy made it look 4.3 times harder than it is. Linda S Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2014 Share Posted April 22, 2014 Perhaps you prefer this one? Quote Link to comment Share on other sites More sharing options...
linda s Posted April 22, 2014 Share Posted April 22, 2014 Yeah great. I made this extra heavy duty custom differential gear system but oh it doesn't fit anything so your going to have to shave and shim until the cows come home. FUN, NOT Linda S So good to see an expert do it. LOL Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2014 Share Posted April 22, 2014 I think the moral of the story is that it's not a job for someone who doesn't know what they're doing. Quote Link to comment Share on other sites More sharing options...
turtle Posted April 22, 2014 Share Posted April 22, 2014 Find a late model V-6 (89-91) 4-runner in a salvage yard near you. Most came with 4.56:1 and some came with 4.88:1 The VIN will tell you what came standard and you can pretty much bet it is still standard as a change means a change to both front and rear dif on a 4x4 If you get the entire dif, it is a simple swap. Almost any shop can do it and many who have automotive experience can do it at home. My 4.56:1 diff came out of a 1991 V-6 4-runner Quote Link to comment Share on other sites More sharing options...
JR67 Posted April 23, 2014 Author Share Posted April 23, 2014 Hi everybody, Thanks for all the replies. Linda; yes plenty not-so-good roads here but I used to do logging roads in a Toyota Matrix so I might be ok with clearance:) I was hoping to keep my 15" wheels and LT tires, but can not find a 7.5" diff with proper gearing. Turtle: the diff's that you mention are from later Toyo's, that are 8" and unfortunately seem to have a different spline count than the 7.5" that I have, so the word is that they are not interchangeable..... If you can prove them wrong I would love to hear your input. Had I known last year that there was a guy in town that specializes in Toyota trucks then I would have replaced the complete rear axle with a later 8" one that have all the gearing options available. Instead I replaced the bearings, brakes and magnafluxed the drive shafts of my original 7.5" axle..... So I guess by now the smaller tires are the best/quickest solution. Last summer I towed my rigid bottom Zodiac with 55hp outboard over 18% steep hills... The only reason I made it up there was that I reached the top before the revs in 1st gear dropped to zero, and the only reason I made it down was the fact that some helpful guys with a truck that actually had working brakes (as opposed to my brakes that I completely smoked) took my boat trailer down the mountain for me. So much for route planners that don't tell you that you are about to take the steepest road in the province..... This year I'll leave the boat trailer home and will start with new front calipers, rotors and pads:) Anyway, we were talking about gear ratios and tires sizes. Since I now plan to go with the original diameter tires, were the stock 18' motor homes geared properly or could they still do with a lower gear ratio? Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 23, 2014 Share Posted April 23, 2014 Those who have swapped for a 4.56 or 4.88:1 seem to be universally happy. Quote Link to comment Share on other sites More sharing options...
turtle Posted April 24, 2014 Share Posted April 24, 2014 The pickup trucks these RVs were made from could cruise at 70-75 mph on the highway when they were empty with the engine turning 2800-3000 rpm or so and just lope along getting great gas mileage The RV you are driving does not need to run at this speed so they do benefit from lowering the gearing in the rear end. 4.56:1 seems the ticket for me as it allows my V-6 to cruise at highway speed but with a 4 cyl and an attitude that 55 is fine 4.88:1 might be a better choice. This is just talk as I have no first hand experience with the lower 4.88:1 gearing and 4 cylinder gas engines. Quote Link to comment Share on other sites More sharing options...
JR67 Posted April 25, 2014 Author Share Posted April 25, 2014 Thanks, I should perhaps pull my diff to see if it is definitely a 7.5" like the vehicle tag suggests(F292) and not an 8". Worst case scenario I can swap the complete rear axle. Decisions decisions..... Quote Link to comment Share on other sites More sharing options...
JR67 Posted May 30, 2014 Author Share Posted May 30, 2014 Quick update: I found that my axle was not equipped with a 7.5" diff and 4.10 ratio as the F292 tag made me believe, but with an 8" diff and 4.10 ratio. So now I am running a 4.56 diff from a 1990 V6 4x4 pickup and all is good, I just needed to drill another bolt pattern in the diff's drive shaft flange. Somebody suggested to mate two halves of the new and old u joint with the different bolt patterns but the u joint cups are of a different diameter so that plan didn't work. Drilling was only half an hour work though. I don't see why Toyota would put on a misleading tag, but maybe the cab was originally intended for a half ton truck and ended up on my Cab&Chassis that (depending on what parts suppliers catalog you open) is a 3/4 ton, one ton or heavy duty pickup. It was Canadian build, maybe that explains this, or maybe not? Quote Link to comment Share on other sites More sharing options...
zero Posted May 31, 2014 Share Posted May 31, 2014 I had that pinion-flange problem when I put a 1988 FF dually into my 1978 Chinook. Several companies sell universal-fit flanges drillers for mutlitple Toyota u-bolt patterns. In my case - I just swapped the Hotchkiss center-sections. I.e. took the 1978 center-section and swapped it into the 1988 unit. I could not swap flanges because the spline-counts were different. They were both 7.8" Toyota units - what's commonly called the Toyota "4 cylinder 8"" differential. Just finishing putting 4.56 gears in my 1988 Mini-Cruiser. I could not find any 4.56 diffs locally. I bought a new gear set and installed it. $230 for the gears and another $40 in parts for what's needed for the install. New crush collar, shim pack, and pinion bearings. If was not all that difficult to set up. No special tools needed other then a press. My biggest problem was figuring what brand gears to buy. Yukon sells ring and pinion sets under two names. U.S.Standard Gear and Yukon. The U. S.Standard Gear version is only $130 and was very tempted to buy. Ends up they are Yukon rejects that are considered "less then perfect" and thus half the price. I chickened out and bought the higher-priced version. So the new and ring and pinion install is costing me $270, plus another $80 for a speedometer adapter to get the speedo working correctly. I Quote Link to comment Share on other sites More sharing options...
chefdave Posted June 2, 2014 Share Posted June 2, 2014 Hi slightly on topic how much diff oil is required to refill diff. Thanks Quote Link to comment Share on other sites More sharing options...
zero Posted June 2, 2014 Share Posted June 2, 2014 Hi slightly on topic how much diff oil is required to refill diff. Thanks Just shy of two US quarts. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted June 2, 2014 Share Posted June 2, 2014 Oddly enough, the 1992 Owners Manual lists the following for the differential:- Oil Capacity 2 Wheel Drive Models 22R-E engine -- 1.35 liters 3VZ-E engine -- Rear Single wheels -- 1.8 liters -- Rear Dual wheels -- 2.2 liters You can compare it with what's written in the Maintenance section of the FSM (pg 15):- http://personal.utulsa.edu/~nathan-buchanan/93fsm/maintenance/2maint.pdf and the Differential section of the FSM (pg 3):- http://personal.utulsa.edu/~nathan-buchanan/93fsm/suspensionandaxle/35differen.pdf I guess the bottom line is that you might chose to have a 3rd liter of oil on hand if you're doing a complete change. You can always return it. Keep the receipt! Quote Link to comment Share on other sites More sharing options...
zero Posted June 3, 2014 Share Posted June 3, 2014 Makes sense for a dually FF. There are extra cavities to fill with oil due to the bearing-hubs added at the ends. Quote Link to comment Share on other sites More sharing options...
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