coolwind57 Posted April 17 Share Posted April 17 I'm suspecting that the shifting issues of my AW4 auto may be caused by a bad speed sensor. I'd already replaced and properly set a new TPS, I bought and replaced my TCU with a junkyard one, and my NSS is only 2-3 years old, so I'm feeling good that it is still good. I tested my shift solenoids and they were all good. My next move is to replace the speed sensor. I recently bought a Standard Products SC129 speed sensor from PartsHawk like the one pictured. I was under the impression that the location of the speed sensor was behind the 4x4 shift bracket. Man, that was a pain to remove. Anyhow, I was either wrong on the location of I just have the wrong part. The part under that bracket looks nothing like the SC129. The part on my truck has what appears to be a rubber line running to it and no electrical connection at its base (see the end of my finger): I've been looking all over the internet but I'm not really coming up with anything to solve my issue. Anyone with experience swapping the speed sensor out? I've scanned all over my AW4 transmission and I cannot figure out another location where SC129 would go. Is the part pictured at the end of my finger the actual speed sensor? Do I have the wrong part? Am I overlooking the area where the SC129 would go? Link to comment Share on other sites More sharing options...
llhat Posted April 18 Share Posted April 18 not sure if this thread will help, but gives on advice. https://www.jeepforum.com/threads/aw4-troubleshooting.4244314/ page 23 of this pdf file may be or assistance location in the adapter housing to transfer case (much later years it is on the output of the transfer case) there's also test procedure (but i think this publication is actually for later vehicles) https://cdn.xjjeeps.com/pdf/en-us/aw4-transmission-service-information.pdf Link to comment Share on other sites More sharing options...
coolwind57 Posted April 19 Author Share Posted April 19 22 hours ago, llhat said: not sure if this thread will help, but gives on advice. https://www.jeepforum.com/threads/aw4-troubleshooting.4244314/ page 23 of this pdf file may be or assistance location in the adapter housing to transfer case (much later years it is on the output of the transfer case) there's also test procedure (but i think this publication is actually for later vehicles) https://cdn.xjjeeps.com/pdf/en-us/aw4-transmission-service-information.pdf Thanks for taking the time to respond. I didn’t see anything on the transfer case. I did see a guy on YouTube swapping one out and his was near the output of the transfer case. Mine is not. Link to comment Share on other sites More sharing options...
coolwind57 Posted April 19 Author Share Posted April 19 I think I’ve just got the wrong part. Link to comment Share on other sites More sharing options...
Ωhm Posted April 19 Share Posted April 19 Crown automotive sales Link to comment Share on other sites More sharing options...
coolwind57 Posted April 19 Author Share Posted April 19 8 hours ago, Ωhm said: Crown automotive sales Thanks Omn. I did see this part as well, very different from the one that I purchased. I’m assuming I just purchased the wrong part even though application shows it is correct. I will purchase this and see what happens Link to comment Share on other sites More sharing options...
coolwind57 Posted April 20 Author Share Posted April 20 12 hours ago, Ωhm said: Crown automotive sales Ok, this thing is $110 and is harder than hell to find. Crown makes it and you can only purchase through an authorized dealer. One dealer showed that the part does not fit my 89 Jeep Comanche. Another, Jegs, says that same part does fit, and can get it but they have no estimate on when they can ship (I'm assuming they'd drop ship from Crown). This thing must be like hen's teeth. Very difficult to find anything about this part on the internet. Anyhow, unless I can find a way to test mine, I'm not sinking that much money on a part that I'm not sure is correct for my application and with me guessing if it would fix my issue. I'm now leaning towards taking the truck to an transmission shop and giving up on troubleshooting and shotgunning parts. Frustrating. Link to comment Share on other sites More sharing options...
llhat Posted April 20 Share Posted April 20 believe i linked info on testing your sensor above.... Link to comment Share on other sites More sharing options...
Flexj Posted April 22 Share Posted April 22 Any chance your getting bad search results from it being confused with the toyota version of the AW4? Toyota used it in the second and maybe third gen 4runners also... Might be why its showing a speed sensor you don't have. With that being said ive only had manual jeeps never an AW4 but ive never seen the speed sensor anywhere except the t case near the output on any 90s and older jeep... Correct me if I'm wrong but id need a picture of your t case and then id be very surprised if it indeed didnt have any speed pickup sensor there. Picture attached is a google search of the part I am referring to. Link to comment Share on other sites More sharing options...
coolwind57 Posted April 27 Author Share Posted April 27 Removed my NSS Neutral Safety Switch, which was only a few years old. Took it apart and it looks fairly new inside. Swapped out with a new one that i got for like $35 and tested my transmission. Shifted normally. PROBLEM FIXED. I thought the NSS was a long shot. Again, internals looks good so I suppose a wiring/connector/harness issue maybe I don't know. Just glad I'm back on the road. Missed my truck. On 4/22/2025 at 1:03 PM, Flexj said: Any chance your getting bad search results from it being confused with the toyota version of the AW4? Toyota used it in the second and maybe third gen 4runners also... Might be why its showing a speed sensor you don't have. With that being said ive only had manual jeeps never an AW4 but ive never seen the speed sensor anywhere except the t case near the output on any 90s and older jeep... Correct me if I'm wrong but id need a picture of your t case and then id be very surprised if it indeed didnt have any speed pickup sensor there. Picture attached is a google search of the part I am referring to. I've confirmed that the SC29 is not on this transmission or transfer case. Even though it shows it fits my 89, it does not. Appreciate your response. On 4/22/2025 at 1:03 PM, Flexj said: Any chance your getting bad search results from it being confused with the toyota version of the AW4? Toyota used it in the second and maybe third gen 4runners also... Might be why its showing a speed sensor you don't have. With that being said ive only had manual jeeps never an AW4 but ive never seen the speed sensor anywhere except the t case near the output on any 90s and older jeep... Correct me if I'm wrong but id need a picture of your t case and then id be very surprised if it indeed didnt have any speed pickup sensor there. Picture attached is a google search of the part I am referring to. On 4/20/2025 at 12:01 PM, llhat said: believe i linked info on testing your sensor above.... This was my next step after the NSS repladement. Glad I didn't have to bother. Thanks for the response. Link to comment Share on other sites More sharing options...
Flexj Posted April 27 Share Posted April 27 39 minutes ago, coolwind57 said: Removed my NSS Neutral Safety Switch, which was only a few years old. Took it apart and it looks fairly new inside. Swapped out with a new one that i got for like $35 and tested my transmission. Shifted normally. PROBLEM FIXED. I thought the NSS was a long shot. Again, internals looks good so I suppose a wiring/connector/harness issue maybe I don't know. Just glad I'm back on the road. Missed my truck. I've confirmed that the SC29 is not on this transmission or transfer case. Even though it shows it fits my 89, it does not. Appreciate your response. This was my next step after the NSS repladement. Glad I didn't have to bother. Thanks for the response. Glad you got it fixed! Happy Jeeping! Link to comment Share on other sites More sharing options...
llhat Posted April 27 Share Posted April 27 14 hours ago, coolwind57 said: Removed my NSS Neutral Safety Switch, which was only a few years old. Took it apart and it looks fairly new inside. Swapped out with a new one that i got for like $35 and tested my transmission. Shifted normally. PROBLEM FIXED. I thought the NSS was a long shot. Again, internals looks good so I suppose a wiring/connector/harness issue maybe I don't know. Just glad I'm back on the road. Missed my truck. Congratulations !!! Glad the source of the issue was discovered... ? Did you try your old TCU after the NSS? or was that someone else that purchased a TCU and the problem was not resolved? Link to comment Share on other sites More sharing options...
coolwind57 Posted May 2 Author Share Posted May 2 On 4/27/2025 at 12:52 PM, llhat said: Congratulations !!! Glad the source of the issue was discovered... ? Did you try your old TCU after the NSS? or was that someone else that purchased a TCU and the problem was not resolved? Honestly, I hadn't put the original one back in to try. I've been so happy with having my truck back that I've been delaying trying it. I spent over a hundren dollars for the eBay TCU....Almost want to put it up for sale to get my money back, but then again it would be nice to have it on the shelf as a back up with my luck. Link to comment Share on other sites More sharing options...
llhat Posted May 2 Share Posted May 2 1 hour ago, coolwind57 said: Honestly, I hadn't put the original one back in to try. I've been so happy with having my truck back that I've been delaying trying it. I spent over a hundren dollars for the eBay TCU....Almost want to put it up for sale to get my money back, but then again it would be nice to have it on the shelf as a back up with my luck. i can understand that joy of having something 'fixed' guess the same reason I did not 'test' the 'other' TCU i purchased as a spare... I have it marked 'untested' on shelf ; my original is marked 'bad'.... it would be a good selling point for your original to know if 'working' or not... I am 'in' for the over hundred each for the ones I bought also. yes, these TCU have a big asking price... and are always questionable for operation. Link to comment Share on other sites More sharing options...
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