ClassySoob Posted January 28, 2019 Share Posted January 28, 2019 Hello all. I have a 85 GL with the dual range 4wd I've noticed a problem with my rear differential. When I have it in 4 hi or low it feels tougher to move the car. And when I this moving, it wants to pull hard to the left. When I back up there is a lot of resistance. And difficulty disengaging the 4wd. Link to comment Share on other sites More sharing options...
czny Posted January 28, 2019 Share Posted January 28, 2019 (edited) There is no center differential - in 4 hi/lo its locked front & rear. You don't need 4wd on pavement or hard packed ground. It will torque bind then. Are you sure the rear diff is 3.90 ratio? Look for a decal on cover. Try shifting out of 4wd in 1st at slow speed. Edited January 28, 2019 by czny 1 Link to comment Share on other sites More sharing options...
FerGloyale Posted January 28, 2019 Share Posted January 28, 2019 (edited) mismatched tires or using 4wd on the wrong terrain (or both) 4wd is only for use in slippery or loose traction. And do not try to turn tightly in 4wd even in hard pack and gravel, use 3 point or 5 point to turn around. Disengage 4wd BEFORE you exit slippery terrain. Rolling very slow in straight line. BEFORE you get to any pavement or hard pack. sometimes it is needed to roll back and forth but always in straight line and still while on the loose surface, be it dirt, mud, snow, sand ect. Edited January 28, 2019 by FerGloyale 2 Link to comment Share on other sites More sharing options...
DaveT Posted January 28, 2019 Share Posted January 28, 2019 Make sure all 4 tires are same make model inflation pressure and mileage / wear. In a straight line, even on dry pavement, it shouldn't make a large change, but I can usually feel / hear a small change - with 4 brand new tires. Link to comment Share on other sites More sharing options...
ClassySoob Posted January 28, 2019 Author Share Posted January 28, 2019 All my tires are Toyo Eclipses, but the front are 175/70/R13s and the rear are 185/70R13s Could this be it? Link to comment Share on other sites More sharing options...
czny Posted January 28, 2019 Share Posted January 28, 2019 9 minutes ago, ClassySoob said: All my tires are Toyo Eclipses, but the front are 175/70/R13s and the rear are 185/70R13s Could this be it? Certainly doesn't help. Tires need to be ALL of same diameter. Link to comment Share on other sites More sharing options...
DaveT Posted January 28, 2019 Share Posted January 28, 2019 Definitely. Link to comment Share on other sites More sharing options...
ClassySoob Posted January 28, 2019 Author Share Posted January 28, 2019 Okay. I'll play around with tire position and see if that may help it. Thanks Link to comment Share on other sites More sharing options...
DaveT Posted January 28, 2019 Share Posted January 28, 2019 Doesn't matter which pair are bigger / smaller. All have to be the same. Link to comment Share on other sites More sharing options...
idosubaru Posted January 28, 2019 Share Posted January 28, 2019 3 hours ago, ClassySoob said: When I have it in 4 hi or low it feels tougher to move the car. You’re not supposed to do that. If you have an owners manual read how to use the 4WD, if not maybe you can find one online here or eBay. Link to comment Share on other sites More sharing options...
ClassySoob Posted January 28, 2019 Author Share Posted January 28, 2019 4 minutes ago, idosubaru said: You’re not supposed to do that. If you have an owners manual read how to use the 4WD, if not maybe you can find one online here or eBay. I do know how to use the 4wd. I have had this car for years and gone all over the mountains with it with no problem at all. But it's not operating as it normally does. That is why I am asking. Link to comment Share on other sites More sharing options...
idosubaru Posted January 28, 2019 Share Posted January 28, 2019 1 hour ago, ClassySoob said: Okay. I'll play around with tire position and see if that may help it. Thanks Why not keep it in 2WD? If you don’t have a rear LSD put one of each tire size on the front and one of each on the rear. The shops around here put the same size on the opposite sides. So put one 185 size on the front right and one on rear left. And the 175s on the remaining locations. 59 minutes ago, DaveT said: Doesn't matter which pair are bigger / smaller. All have to be the same. Some shops do what I mentioned above. I’m not recommending it but they get away with it and it would maybe be an alternative to what he is currently doing and for a couple days while he plans a proper remedy/diagnosis/repair. Link to comment Share on other sites More sharing options...
DaveT Posted January 28, 2019 Share Posted January 28, 2019 Yeah, for temporary. I have run non identical pairs, but kept them front & back. And only use the 4WD for getting moving on wet or snow. No long term 4WD running. Usually did it to use up an odd pair of tires from a parts car, during the summer when I rarely need 4WD. Link to comment Share on other sites More sharing options...
idosubaru Posted January 28, 2019 Share Posted January 28, 2019 7 minutes ago, ClassySoob said: I do know how to use the 4wd. I have had this car for years and gone all over the mountains with it with no problem at all. But it's not operating as it normally does. That is why I am asking. Ah good. You mentioned binding in 4WD which is normal / they all do that. Could you describe what is doing a little better ? Its doing it while doing straight, while off-road...? brakes ? Axles? noises? driveshaft? how long has it had mismatched tires? It really needs the right size even same size tires warn differently can impact transmissions You can Google tire size calculator and you can look up the tire size diffenremce to see how far off they are or measure the circumference of them and compare Link to comment Share on other sites More sharing options...
el_freddo Posted January 28, 2019 Share Posted January 28, 2019 7 hours ago, ClassySoob said: All my tires are Toyo Eclipses, but the front are 175/70/R13s and the rear are 185/70R13s Could this be it? That’s your issue. Use a tyre calculator thingy and you’ll get two different rolling lengths/circumference/diametre. Not by much but it will count. Just like putting the wrong diff ratio in the rear end. One set of axles is trying to rotate faster than the other one. It’ll run just fine in 2wd, no doubt about that. But in the slippery stuff either the front end will drag the arse end around or you’ll have a tail happy arse end that’s trying to get past the front end - much like a highly excited dog running around. Cheers Bennie Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted January 28, 2019 Share Posted January 28, 2019 (edited) I admit to being ignorant of this type transmission, but, running the odd size pair on one SIDE , or opposite corners, might avoid binding if the rear and front diffs are 'open'. best is 4 IDENTICAL tires; brand, size and model. Also, near each other in wear. Subaru has always claimed the rolling circumference needs to be within 1/4" . Edited January 28, 2019 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
czny Posted January 28, 2019 Share Posted January 28, 2019 Until you can get 4 tires all same size, tread, etc, put the 185's on RH side & 175's on LH to see if it follows crown of the road better on black ice & snow road conditions. Being that you're in McCammon ID just S of Pocatello I can imagine that's what you're driving in at times. Until the plow gets there that is. Thanksgiving day & Friday after 2018 was spent driving from Troy MT to Tonasket WA(250 mi ea way) by way of WA20 over two 5000+ ft passes covered in crunchy snow & black ice, mostly in 4Hi. When things got loose in back I just turned front wheels slightly to plow the other way. But all 4 tires on my 87 GL are of same size, etc. with LSD in rear. Sherman Pass(5300ft) was closed just after I got thru on that Friday, as I learned at Beaver Lodge. Near white-out conditions with freezing fog in places. Fun, fun, fun. Link to comment Share on other sites More sharing options...
idosubaru Posted January 28, 2019 Share Posted January 28, 2019 48 minutes ago, 1 Lucky Texan said: I admit to being ignorant of this type transmission, but, running the odd size pair on one SIDE , or opposite corners, might avoid binding if the rear and front diffs are 'open'. It's 2WD when 4WD isn't selected has a mechanical center diff instead of VLSD like EJ's, but they're similar enough that some rear extension housings/center diffs and some internal EA and EJ trans guts can be swapped. 1 Link to comment Share on other sites More sharing options...
FerGloyale Posted January 28, 2019 Share Posted January 28, 2019 16 minutes ago, idosubaru said: It's 2WD when 4WD isn't selected has a mechanical center diff instead of VLSD like EJ's, but they're similar enough that some rear extension housings/center diffs and some internal EA and EJ trans guts can be swapped. There is no center diff. It is just 2wd or 4wd not AWD. 3 Link to comment Share on other sites More sharing options...
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