I have search and search and my problem seams to be, as usual, one of a kind. I have a 99 1500 4x4 5.2L. Truck has 157K, motor is 01 with 88K, trans has 3K since rebuild, Tcase has about 30K. As you can see it would of been cheaper to build from ground up. Anyway, 9 months ago I kept loosing oil pressure, just for seconds, then it would come back. I ended up putting new pump and screen in it and still is intermittent on pressure. Then my speedo is jumping all over, it will work fine then all of a sudden it will jump to 120, 0, and back to normal. Everyone that complains about speedo problem says won't work until 30mph. Mine has never done that. I eventually got a P0720 code, so I changed the output speed sensor on Tcase for the second time. Still have problem, so I changed the ABS speed sensor. Two hours later now I have a CEL, ABS, and Brake light on. I have checked wires, and connectors. The trans is going in and out of lock-up, and it will start of in 3rd or 4th gear sometimes. I am assuming due to the speedometer reading, I can manually shift it to eliminate the high gear take-offs. It always trips a P0720 code and has only had ABS and Brake light on the one time. I was starting to think it was PCM, so I unplugged connectors and cleaned them and checked wires. I am believing maybe it is my gauge cluster at this point. Anyone had this problem or can give me any advise would be greatly appreciated. Just trying to think maybe all my problems could relate to bad cluster. By the way gauge cluster self test checks out ok. Thanks

 

you have a lot of problems.

so changing the speed sensor in the t-case is doing nothing, right ?

and changing the rear diff speed/abs made things worse, by triggering ABS/Brake light on the dash, right ?

have you tried re-installing the original rear diff sensor to get rid of ABS light. it sounds like something went bad with that job.

also sounds like oil pressure gauge and speedo are whacko in the cluster, and you have a transmission problem that may or may not be related.

a cluster problem could explain the gauges, but i don't think it explains the shifting problems. that sounds like a wiring problem, or pcm problem.

you can pickup a cluster on ebay pretty cheap, just get the same year (more or less) and same trans (auto) and gas (not diesel), and be aware the mileage is stored in the cluster, if you care.

i'd consider the transmission problem the most serious and i'd take it back to the trans shop that did the rebuild and ask them to look at it. the problem should/might be under warranty. i wouldn't mention the other problems to them. let them focus on trans only.

 

If the P0720 code is an output speed sensor I think it may be the transmission sensor. Not sure of the sensor on the Tcase you are referring to but I was getting an output speed sensor code and mine wouldn't shift out of first, and it was the output speed sensor on the transmission. That may be the problem with the shifting.

 

If the P0720 code is an output speed sensor I think it may be the transmission sensor. Not sure of the sensor on the Tcase you are referring to but I was getting an output speed sensor code and mine wouldn't shift out of first, and it was the output speed sensor on the transmission. That may be the problem with the shifting.

same thing happend to me and yes its in the tranny i got licky and just manuly shifted it for a week or soo and it just started workin fine lol o and if u end up needing a new cluster got one ill part with for $35 pluse shippin

 

Yes dhvaughan it has been an adventure. The output sensor didn't help, the abs speed sensor only tripped a code once and it hasn't returned yet. I am thinking about puting the old one back in. As far as the tranny. my tranny guy said he could install a new solenoid, that is what he says is wrong. But he also agrees with me. The only reason the tranny is messing up is because the speedo is messing up. When the speedo registers 80mph when I am only doing 15mph it tells the tranny to shift to high gear. When the speedo is twitching up and down 10mph at a time it is telling the tranny to go in and out of lock-up. Basically it all sounds good and makes sense but it gets costly to keep guessing. I have a scan tool, I just haven't been lucky enough to have it hooked up when the speedo is messing up. If it reads fine while my speedo is messing up then to me it has to be the cluster. Thanks for all the input and keep it coming if you have anymore. My tranny was rebuilt by a local friend and I'm sure he will work with me. Atleast I hope so.

 

Hey silverbullet, I might be interested in that cluster. Email me info on it. Mine is a 99 5.2L auto with tach. Don't really care what miles are, be nice if it is not to much higher than mine. I have around 157K. Where are you located and any idea on shipping price? My email is runyonracing@yahoo.com