SouthTex4x4 Posted July 10, 2009 Share Posted July 10, 2009 I have a 1995 PFXE with an auto tranny. I have just hit 100,000 miles and the truck has always ran perfect, until now. The trans has and still does shift nice and easy. Well today after work I get in and it will not go in reverse, talk about a shock, the worst part is I live 50 miles from work. Well I put it in drive and no prob. I drove all the way home like nothing ever happened. Kind of strange but I am hoping for some good feed back here, honestly a quick fix would be much better. I have searched the site and did not find a simular issue and the FSM I looked up gave me a few ideas but what I am hopping for here is someone that has had he same experience or better yet a solution Sorry to ramble on folks but it is frustrating to have you truck just decide to choke up on you. Any suggestions??? I just hope I don't have to rip out the tranny. Thanks, K.C. Link to comment Share on other sites More sharing options...
adamzan Posted July 10, 2009 Share Posted July 10, 2009 How long has it been since the fluid has been changed? Link to comment Share on other sites More sharing options...
Kingman Posted July 10, 2009 Share Posted July 10, 2009 The stock cooler clogs up and deprives the transmission of fluid and so it has no way to dissipate the heat. The reverse brake clutch is the weakest of them all, so it burns out first. Almost always, no reverse signals the impending death of the transmission as a whole. Take it in and have the valve body flushed out, there's always the possibility that a particle is clogging a ball valve in there. I'd be willing to bet your cooler is clogged, and the only thing you can go about that is install an aftermarket unit and completely bypass the stock one. Or, it could be your linkage is messed up and not engaging reverse. Link to comment Share on other sites More sharing options...
SouthTex4x4 Posted July 10, 2009 Author Share Posted July 10, 2009 How long has it been since the fluid has been changed? I would have to say less than 5,000 miles. The fluid looks clean and smells new. Link to comment Share on other sites More sharing options...
SouthTex4x4 Posted July 10, 2009 Author Share Posted July 10, 2009 (edited) The stock cooler clogs up and deprives the transmission of fluid and so it has no way to dissipate the heat. The reverse brake clutch is the weakest of them all, so it burns out first. Almost always, no reverse signals the impending death of the transmission as a whole. Take it in and have the valve body flushed out, there's always the possibility that a particle is clogging a ball valve in there. I'd be willing to bet your cooler is clogged, and the only thing you can go about that is install an aftermarket unit and completely bypass the stock one. Or, it could be your linkage is messed up and not engaging reverse. I would like to think it could be a cooling issue due to the fact that is has been an average of 106 degrees here lately. The temp gauge pretty much stays at normal so should I start with the flush first? Edited July 10, 2009 by SouthTex4x4 Link to comment Share on other sites More sharing options...
Kingman Posted July 10, 2009 Share Posted July 10, 2009 (edited) The engine temperature doesn't have much at all to do with the transmission temperature as they are in separate coolers, and it's easy to overheat a transmission if the cooler clogs. The stock cooler is a known failure point, because it's a fin style and once it's clogged by debris it CANNOT be cleaned out and WILL destroy your transmission if left unattended to. Edited July 10, 2009 by Kingman Link to comment Share on other sites More sharing options...
SouthTex4x4 Posted July 10, 2009 Author Share Posted July 10, 2009 The engine temperature doesn't have much at all to do with the transmission temperature as they are in separate coolers, and it's easy to overheat a transmission if the cooler clogs. The stock cooler is a known failure point, because it's a fin style and once it's clogged by debris it CANNOT be cleaned out and WILL destroy your transmission if left unattended to. I will go ahead and change out the cooler, not a problem. I was just curious as to why I only have the problem with the reverse gear and all the others work fine. If the fluid is causing problems would it not effect the functionality of all gear ranges? In any case when I do change out the cooler and the problem is still present, do I need to consider the reverse clutch? If this is indeed the case will this require the removeal of the tranny and will I have to completely rebuild the unit or just tend to the reverse clutch? Man this is getting deep, whatever happened to the quick fix? Anyway, I really appreciate your help in this matter. This is the first time that I have had to deal with this type of issue, usually I just remove the tranny and send it down to the local shop and they benchwork it. I am told the Nissan trannys tend to get expensive if you take it to a shop. Thanks, Link to comment Share on other sites More sharing options...
adamzan Posted July 10, 2009 Share Posted July 10, 2009 Some people even have trouble finding people to work on them. I had an intermittent no reverse but I flushed my tranny twice and it seems to have fixed the problem. I guess it was just dirty. The fluid was dark when I bought it. Was the fluid always changed at the correct interval on your truck? If it was neglected it may also explain why this has happened. Link to comment Share on other sites More sharing options...
k9sar Posted July 10, 2009 Share Posted July 10, 2009 my first tranny failure was exactly as you describe. Reverse was the first to go but FWD gears were fine. The tranny shop who worked on it told me that reverse requires a higher line pressure and he suspected my pump was going bad. Sure enough, the pump had failed and smoked the reverse gear which subsequently ate the planetary assembly. I fear that you are on the brink of a catestrophic failure and would get it torn into ASAP. Link to comment Share on other sites More sharing options...
SouthTex4x4 Posted July 10, 2009 Author Share Posted July 10, 2009 (edited) Thanks for the feedback! Should I flush the unit first to see if it help's? Or just go ahead and drop the unit? If I do a flush and it works, how long will it last. If I drop the unit would I be able to repair just the reverse clutch or would I have to tackle the whole tranny? I am not running the truck now so i can do what is necessary to get this fixed. K.C. Edited July 10, 2009 by SouthTex4x4 Link to comment Share on other sites More sharing options...
Precise1 Posted July 10, 2009 Share Posted July 10, 2009 It can't hurt to flush the tranny again, but no promises that it will do any good, the damage may already be done. I won't speculate as to how long it would work either. I didn't see anyone mention it so I will. Bypass the stock tranny cooler completely and install an aftermarket unit, the bigger the better. There are several write ups on it. The engine temperature doesn't have much at all to do with the transmission temperature as they are in separate coolers, I don't really agree with this. The tranny cooler is the bottom part of the radiator. If the radiator is hot, it limits how cool the tranny fluid can get, another reason why external coolers are superior... B Link to comment Share on other sites More sharing options...
Kingman Posted July 10, 2009 Share Posted July 10, 2009 (edited) It can't hurt to flush the tranny again, but no promises that it will do any good, the damage may already be done. I won't speculate as to how long it would work either. I didn't see anyone mention it so I will. Bypass the stock tranny cooler completely and install an aftermarket unit, the bigger the better. There are several write ups on it. install an aftermarket unit and completely bypass the stock one. I don't really agree with this. The tranny cooler is the bottom part of the radiator. If the radiator is hot, it limits how cool the tranny fluid can get, another reason why external coolers are superior... B You got me there B. I wasn't thinking very clearly (vikadin) Just from my experience, flushing the fluid and installing an external cooler completely did away with the symptoms of my problems. On the way back from my ex's house, my transmission started shifting at the worst times, reverse took forever to engage then did with a BANG. I installed a cooler, flushed the fluid, and the problems all went away. That was nearly 5,000 miles ago and not a hiccup since. I would go straight ahead with installing an aftermarket unit and flushing, and even if that doesn't fix this transmission, it will save the next one from the same death. Edited July 10, 2009 by Kingman Link to comment Share on other sites More sharing options...
SouthTex4x4 Posted July 10, 2009 Author Share Posted July 10, 2009 (edited) Great stuff guy's! I will get started this week end. I did find the post on the tranny cooler install last nightand and I don't see any hang ups there, it looks to be a cut and dry install. As for the flush it sound like I will have to do it twice in order to get the fluid out of the converter. I have been working on trucks for quite a number of years now but I have to admit the info that comes from this forum really makes one's life easier. I let you know how things turn out. Thanks again!! Edited July 10, 2009 by SouthTex4x4 Link to comment Share on other sites More sharing options...
nismothunder Posted July 14, 2009 Share Posted July 14, 2009 I thought the 94-95 pathys had the tranny cooler problem solved by the factory.Since the 94-95 rads are not the same as earlyer models? Link to comment Share on other sites More sharing options...
Precise1 Posted July 14, 2009 Share Posted July 14, 2009 I had not heard that nor did I know the radiator is different. I'm not going to gamble though... B Rock auto shows the same radiator for 1990 and 1995, but this doesn't mean that its the same for oem. Link to comment Share on other sites More sharing options...
Kingman Posted July 14, 2009 Share Posted July 14, 2009 They are the same cooler, however a recall was issued and SOME were flushed out and SOME were bypassed with an aftermarket unit free of charge. Link to comment Share on other sites More sharing options...
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