Hi Everyone,

A member suggested I post to the Discovery 1 section. I'm new on here, but not to P38's. I do have a head scratcher and need some help or some common sense to get me to the next level in my process of elimination. My 98 4.6 HSE has been driving fine for the last 5 years + until late Spring of 21 when it would hesitate from Park after start up to go into gear. Things progressed until it got to the point that you had to roll on adecline about 6 feet to get it engaged into gear. The truck shifted fine after the intial advance, but you had to keep it just barely rolling in order for it to take off normally. My mechanic, who was tied up, couldn't get to it, so I brought it to another guy, who supposedly knew what to do...(you know where this going already right?), so 2 months later, I have a new speed sensor, transmission filter/fluid change, and it's worse. The only way to drive it is with the TCM disconnected and in limp mode (3rd gear). The truck idles fine and runs smooth, but will not engage in all the gears. "Gear Box Fault" comes on the screen and the ABS and Traction Control light stay on (no 3 amigos) plus the check engine light. The latest codes are P1775, P1777, P0722, and P0740. I Bought another Ebay matching TCM to no avail. My guess is a shift sensor or solenoid(s) inside the valve body? a wiring short somewhere? or maybe the Transfercase Shift assembly? I have been looking through RAVE and forums and can't nail it down yet. I don't want to waste time chasing rabbits. Any help would greatly appreciated.

 

As a D1 and P38 owner myself, I'm fairly certain both use different transmissions. 4HP22 vs 4HP24. The D1's trans doesn't really use any control modules or anything like the P38's trans does so the D1 forum may be of limited help since the D1 is more "old school" in its running gear and drivetrain. At the risk of getting "competition" involved, I would suggest perhaps posting on rangerovers.net, or rangerovers.pub. The latter site is mostly P38 owners - i use both forums regularly for my P38 concerns, which have fortunately been few and far between!

Good luck!

 

The DII has more in common with the P38 than the D1. I also own both and I Gene, I can't tell you how jealous I am of your P38. I bought it two months ago and have been chasing one problem after the next. But man is it a nice truck!

 

I will say, having a Nanocom is indispensible if you plan on entertaining P38 ownership. I literally ordered mine on the road when i picked up my P38 in Denver 4 years ago.

That said - given the issues and errors with the trans..... how old is the battery on your truck? I've heard rumors that if the battery is old and/or on its way out, certain systems are more sensitive to voltages (or lack thereof) and can do odd things. I experienced similar on my e34 Touring shortly before i dumped the auto trans for a manual.... the dreaded "TRANS PROGRAM" error, which is similar the the "GEARBOX FAULT" on a P38. Checked battery voltage, and while the car would still start, it was less than nominal voltage. Put a new battery in and I never saw the warning again. So, something easy to check on.

 

I will give it a check! 13.4 volts or so right?