bratlife Posted March 7, 2011 Share Posted March 7, 2011 Hi there, I have had a ton of help from a bunch of you on here in the past and I really appreciate it. It is the reason that my brat is still on the road these days, even at just over 300k miles now. But, I have some more questions, that hopefully some of you could help me out with. I have an 85 brat thats running great these days, but having some drive line issues. the u joints on the front end of the drivetrain ( the end that is up against the back of the differential) is completely shot, so I'm replacing that as soon as the new ones come in. But I am worried that there is more to the vibrating than just the u joints. How can I tell if the differential is going out? thanks a lot for any thoughts you all might have on this. Quote Link to comment Share on other sites More sharing options...
nickolai Posted March 7, 2011 Share Posted March 7, 2011 Bad U-joints can make it feel like the whole car is falling apart. Replacing them will have a dramatic impact on shaking. I can't say for sure but I bet this is your whole problem. Quote Link to comment Share on other sites More sharing options...
Deener Posted March 7, 2011 Share Posted March 7, 2011 I know from experience that if your fluid is black instead of gold, then you can expect some trouble. My front diff started a high pitch whining when it was on it's way out. It was a very distinct sound - like that of a remote control car...not sure if that helps you much though. Quote Link to comment Share on other sites More sharing options...
bratlife Posted March 7, 2011 Author Share Posted March 7, 2011 thanks a bunch for the replies. I was thinking it was more than just the rear u joints because the vibration is still pretty crazy even when just in 2wd. its worst at around 30mph and gets pretty bad again around 50 mph. It was rattling so bad that everything around the whole car was making noise. Still think it is just u joints? I have to change them either way. thanks again for the help. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted March 7, 2011 Share Posted March 7, 2011 I know from experience that if your fluid is black instead of gold, then you can expect some trouble. My front diff started a high pitch whining when it was on it's way out. It was a very distinct sound - like that of a remote control car...not sure if that helps you much though. Mine did the same but it was because the oil seal leaked and it ran dry... from the time I heard it (I was at speed) from just taking off from a stop light slowly it just ate it's self apart.. 2003 FXS Quote Link to comment Share on other sites More sharing options...
bratlife Posted March 8, 2011 Author Share Posted March 8, 2011 So did you end up having to replace the whole thing? Do you know if there is a way to somehow check if it is going out without taking it out? or what part of it is failing, like the outer bearings or something? thanks for any help with this. -scotty Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted March 8, 2011 Share Posted March 8, 2011 you can drain and check the fluid.. in my car the car was an auto and the ring gear blew pieces of the case open. Quote Link to comment Share on other sites More sharing options...
edrach Posted March 8, 2011 Share Posted March 8, 2011 Does the shaking go away when you let off on the throttle and coast? That's a pretty common symptom for a bad inner joint (DOJ) on a front axle. I had it one time so bad it felt like the transmission was about to fall out of the car. Quote Link to comment Share on other sites More sharing options...
nickolai Posted March 8, 2011 Share Posted March 8, 2011 thanks a bunch for the replies. I was thinking it was more than just the rear u joints because the vibration is still pretty crazy even when just in 2wd. its worst at around 30mph and gets pretty bad again around 50 mph. It was rattling so bad that everything around the whole car was making noise. Still think it is just u joints? I have to change them either way. thanks again for the help. My 88 DL was doing exactly what you describe here. Luckily I had a parts car with a good rear drive line in it so I just swapped it out, and all the shaking went away. It doesn't seem to have harmed anything else, and I probly put over 100 miles on it while the shaking was bad. Being in 2wd/4wd has little effect because the rear drive line always turns when the car is moving. Even in 2wd it's being turned by the back wheels. The only disconnect is inside the tranny. Quote Link to comment Share on other sites More sharing options...
cj7135 Posted March 8, 2011 Share Posted March 8, 2011 I know from experience that if your fluid is black instead of gold, then you can expect some trouble. Not really, fluid goes black from being used. It does mean that it's time to change the fluid, but the colour of the fluid has nothing to do with the health of the differential. I agree with Nickolai, U-Joints make the whole car feel like it's about to explode. The only way to tell for sure if your differential is good is to open it up and have a poke around in there. Even then you need a pretty good idea of what you're looking for. IMHO, I think you should change the u-joints and do an oil change on your diffs. If you still have problems then you can start worrying. But unless it's howling extremely loud or making a loud whining noise, I would suggest its good for a lest the foreseeable future. Quote Link to comment Share on other sites More sharing options...
Ricearu Posted March 8, 2011 Share Posted March 8, 2011 even in 2wd the rear differential spins the driveshaft. ujoints can cause this. Grab the yoke of the diff and check for play. if no play, then you are ok to replace the driveshaft. Quote Link to comment Share on other sites More sharing options...
bratlife Posted March 9, 2011 Author Share Posted March 9, 2011 sweet. thanks a lot for all the replies. thats what my plan has been. just swap out the u joints and then see if I still have a problem. Just picked them up this afternoon, so I guess I'll start in on it a soon as I get a chance. probably in a couple days. somebody said something about replacing the entire driveshaft itself. Is there any reason that it can go bad? I was just thinking all I needed to do was replace the u joints and keep using the same drive shaft. any thoughts on this. thanks a lot. Quote Link to comment Share on other sites More sharing options...
naru Posted March 9, 2011 Share Posted March 9, 2011 sweet. thanks a lot for all the replies. thats what my plan has been. just swap out the u joints and then see if I still have a problem. Just picked them up this afternoon, so I guess I'll start in on it a soon as I get a chance. probably in a couple days. somebody said something about replacing the entire driveshaft itself. Is there any reason that it can go bad? I was just thinking all I needed to do was replace the u joints and keep using the same drive shaft. any thoughts on this. thanks a lot. Driveshaft w/original u-joints is probably factory balanced as an assembly. I haven`t heard of any balance problems from replacing u-joints. Matchmark the pieces before disasembly. It is possible to bend a driveshaft. Quote Link to comment Share on other sites More sharing options...
nickolai Posted March 9, 2011 Share Posted March 9, 2011 I was told by a knowledgeable Subaru mechanic that the U-joints in my 88 DL ea82 were not serviceable. That's not to say the ones from ea81/71 cars also aren't. I'm actually hoping maybe someone can tell me for sure either way on the ea81/71 cars because I've got two gen. 1 wagons that need new U-joints and I don't have the luxury of just swapping in another drive line on these cause I don't have any good ones laying around. Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted March 9, 2011 Share Posted March 9, 2011 Rockford driveline sells retrofit ujoints for the staked in style joints that EA82 and newer cars use. Look them up on the net. Quote Link to comment Share on other sites More sharing options...
bratman2 Posted March 10, 2011 Share Posted March 10, 2011 EA81 U joints can be replaced. Quote Link to comment Share on other sites More sharing options...
ferox Posted March 10, 2011 Share Posted March 10, 2011 When was the last time you replaced your transmission mounts? If the answer is "never", then at the very least I would check them out. Ea81 trans mounts are pretty weak. After the driveline vibration you described they may have even pulled apart. If it were me, I would replace them, but I would advise that you at least check them. Their importance in the driveability of the car is usually grossly underestimated. Quote Link to comment Share on other sites More sharing options...
nickolai Posted March 10, 2011 Share Posted March 10, 2011 Thanks for the U-joint info guys. When was the last time you replaced your transmission mounts? If the answer is "never", then at the very least I would check them out. Ea81 trans mounts are pretty weak. After the driveline vibration you described they may have even pulled apart. If it were me, I would replace them, but I would advise that you at least check them. Their importance in the driveability of the car is usually grossly underestimated. Now that you mention tranny mounts it makes me wonder if this could be the reason why the shifter rattles whenever I get above about 2500 rpm in my 88 DL. It's quite annoying. It quiets down if I hold my hand on the shifter, but who wants to do that all the time? The car has almost 250K miles and I think it's the original tranny, so is it just a sign that the tranny's getting tired? Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted March 10, 2011 Share Posted March 10, 2011 No, that's the bushings in the shifter being worn and loose and letting it rattle. You can probably put it in 3rd gear and swing the shifter side to side the same distance as the width of the radio face, right? Quote Link to comment Share on other sites More sharing options...
bratlife Posted March 12, 2011 Author Share Posted March 12, 2011 thanks for all the help. I put in new u joints on both ends yesterday and it is working perfect. All the vibration is gone. I heard that it is a huge pain in the ars to do the u joints, but it all seemed pretty quick and easy I thought. I'm gonna change the diff oil tomorrow as well. I looked at the tranny mounts and they seemed to be alright, but I don't really know what they are supposed to look like either. I mean, its still hangin on there, but I don't know how much play they should have or not. any body have any more specific info on that. Sorry for having late replies to everybody, but I live in a place that doesn't get internet so I gotta drive to the next town every couple of days to check emails and stuff. thanks again for all the help. Quote Link to comment Share on other sites More sharing options...
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