rx7speed Posted January 8, 2013 Share Posted January 8, 2013 Have an 89 GL that is a three speed auto with user selectable awd by a little push button on the shifter. When driving in 2wd it does just fine but when I engage awd the car becomes very unstable. It's almost at that point if the rear end wants to start sliding out even if going in a straight line and almost feels at times if I'm on snow that it is like someone else is either tapping the gas/brake for just the rear wheels only. So far about the only good the awd does for me is the intial take off and once I hit about 10mph I have to shut the awd off or I'm all over the road. Honestly even a RWD car seems to be more stable then this thing and I'm just stumped as to what it is or what is causing this, can someone please offer some advice? Quote Link to comment Share on other sites More sharing options...
HITMAN Posted January 8, 2013 Share Posted January 8, 2013 Are all the tires the same size? Properly inflated? Quote Link to comment Share on other sites More sharing options...
AKghandi Posted January 8, 2013 Share Posted January 8, 2013 ^+1 its not awd its 4x4 so the front and rear diff are connected, its sounds like your rear tires are bigger than the front. Quote Link to comment Share on other sites More sharing options...
l75eya Posted January 8, 2013 Share Posted January 8, 2013 It also sounds like you're using it on improper surfaces. 4WD is not like AWD. It should only be engaged when you're on dirt, mud, or snow. Not pavement. Not wet pavement. If you try and use your 4WD vehicle like an AWD vehicle, you will break stuff. Also, as posted above, if you have any tires on your vehicle that are mismatched, different size, relatively different tread depths even patterns; you are still going to be causing strain to your drive-train. Quote Link to comment Share on other sites More sharing options...
rx7speed Posted January 9, 2013 Author Share Posted January 9, 2013 Checked tire pressure. All tires came out low but about the same +/- 1-2 psi. Did inflate them all up to the pressure listed on the door tag of 28psi for all four corners. Tires are all of same manufacture, model, and size. Tread though is quite heavily worn I admit and chances are they do need replaced but by eye at least seems to be about the same depth. l75eya only real time I use the switch is on snow and very very rare on dirt. There isn't enough power in the car to make the rear end slide around and become unstable on dry/wet ground at any speed or any power. Lol hell this this can't even spin the tires in 2wd mode on dry ground and can hardly get a slight chirp out of them on wet, so yeah it's not me driving around on dry/wet surface but only snow or ice that I'm having this problem. Granted I admit I have turned the switch on in the dry but time was VERY limited and more for a curiousity moment but that was after this all started happening. When I did so though there was no clunks, no bangs, no uneven action from the rear end that I manage to get with the snow. It was all nice and smooth. That is mainly why I did it was due to the issues I have on snow and was trying to see if it would respond on dry the same or at least give some indication that something was wrong. Quote Link to comment Share on other sites More sharing options...
MilesFox Posted January 9, 2013 Share Posted January 9, 2013 mount the mismtached pairs diagonally until you get all 4 same size tires. go with 185/70's but 13's are getting harder to find these days. Quote Link to comment Share on other sites More sharing options...
rx7speed Posted January 9, 2013 Author Share Posted January 9, 2013 that's what is currently on there right now on all four corners. Quote Link to comment Share on other sites More sharing options...
MilesFox Posted January 9, 2013 Share Posted January 9, 2013 Maybe you have a bent rear trailing arm or something wonky with the suspension geometry. These cars have a fixed alignment more or less. Quote Link to comment Share on other sites More sharing options...
rx7speed Posted January 9, 2013 Author Share Posted January 9, 2013 Double checked my tread and think I might of found my problem. Swear I saw the same on fron and back but seems I was wrong. Fronts are border line "racing" tires aka redneck slicks, and the rears while close will cover about half way up lincolns head on a penny. Granted not a huge difference but might be enough. Quote Link to comment Share on other sites More sharing options...
AKghandi Posted January 9, 2013 Share Posted January 9, 2013 (edited) sounds like thats your problem, they need to be as close to the same as possible. check craigs list, you might be able to find some matched tires for pretty cheap. thses are a little spendy but 185/80/r13 are pretty hard to come by. http://boise.craigslist.org/pts/3436051394.html Edited January 9, 2013 by AKghandi Quote Link to comment Share on other sites More sharing options...
rx7speed Posted January 9, 2013 Author Share Posted January 9, 2013 can do and thank you all for the help. just curious is the center in the car clutch or locker based? Quote Link to comment Share on other sites More sharing options...
AKghandi Posted January 9, 2013 Share Posted January 9, 2013 the center diff is a locker. Quote Link to comment Share on other sites More sharing options...
robm Posted January 9, 2013 Share Posted January 9, 2013 It is not a differential at all. It is straight drive, so front and back wheels try to turn at the same speed. At low speeds in tight corners, the rear wheels follow a shorter path than the front, so it is best to not use it on dry pavement under these circumstances as the tires/steering/drive line complain. Also avoid tight corners on ice in 4WD, it will make you slide out. Mismatched tire wear will affect you in 4WD. Put the better tires on the front and they will soon wear the same as the other 2. New tires are getting very hard to find. 175/70-R13 are still fairly available. They are a bit smaller in diameter than 185/70. The bigger tires are better, if you can get them. Quote Link to comment Share on other sites More sharing options...
MilesFox Posted January 10, 2013 Share Posted January 10, 2013 It is not a differential at all. It is straight drive, so front and back wheels try to turn at the same speed. At low speeds in tight corners, the rear wheels follow a shorter path than the front, so it is best to not use it on dry pavement under these circumstances as the tires/steering/drive line complain. Also avoid tight corners on ice in 4WD, it will make you slide out. Mismatched tire wear will affect you in 4WD. Put the better tires on the front and they will soon wear the same as the other 2. New tires are getting very hard to find. 175/70-R13 are still fairly available. They are a bit smaller in diameter than 185/70. The bigger tires are better, if you can get them. ^^^^this^^^. and mount the tires diagonally until you get proper match. Quote Link to comment Share on other sites More sharing options...
rx7speed Posted January 10, 2013 Author Share Posted January 10, 2013 are the front and rear diffs open diffs then? don't want to cause wear on them Quote Link to comment Share on other sites More sharing options...
silverhelme Posted January 10, 2013 Share Posted January 10, 2013 I know it is a long shot and someone else will chime in with the gear ratios but check to see what the ratio on the rear axle is. I bought one a few years ago for next to nothing that had the same symptoms. Someone had put a stick rear differential in it and the 3.9 vs 3.7 made it a real squirrel. I changed to the correct diff and it has worked fine for 8 years. Quote Link to comment Share on other sites More sharing options...
ivans imports Posted January 10, 2013 Share Posted January 10, 2013 gear ratios +1 or planetary damage in trans alowing the front to spin at diferent rate than rear. But most likly mix match ratios Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.