Over Drive and Tachometer Issue
Thread Starter
|
Posting Guru
Joined: Nov 2006
Posts: 1,059
Likes: 0
From: Herndon KY
Over Drive and Tachometer Issue
1992 3/4 ton with a recently rebuilt transmission. 180,000 miles total 20,000 on the new tranny. Been having a problem where the Tach drops to zero, and no matter where you put the selector in any forward gear the tranny selects OD. So you have a choice of OD N R or Park. Can somebody tell me why, and how to fix the Tach problem, when the Tach works so does the Tranny.
Thanks
Bryan
Thanks
Bryan
Lead Driver
Joined: Mar 2006
Posts: 5,105
Likes: 1,523
From: western SD
Sounds like the tach pickup is going bad. It is the one inch nut with two wires coming out of it on the front of the engine. It is a ford only item about 50 bucks from the dealer. Hope this helps.
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
A dead tach sender should/would send the automatic trans into a "failure management mode" (limp mode) with harsh engagements and firm shift feel and an abnormal shift schedule. It has no effect on a manual trans only the Tach readings.
Check the wires where they exit the big nut on the oil filler housing , known to short out due to bare wire.....
Replace the tach sender on the oil fill housing a big 1" nut with 2 wires. Ford only part Engine RPM sensor E5TZ-17B384-A about $50. You can remove and clean it but usually changed later too.
You can test it too, hold it in the air away from ferrous metal, using an ohm meter lead on each wire you need DC resistance between 2000-3000 ohms.
Check the wires where they exit the big nut on the oil filler housing , known to short out due to bare wire.....
Replace the tach sender on the oil fill housing a big 1" nut with 2 wires. Ford only part Engine RPM sensor E5TZ-17B384-A about $50. You can remove and clean it but usually changed later too.
You can test it too, hold it in the air away from ferrous metal, using an ohm meter lead on each wire you need DC resistance between 2000-3000 ohms.
Thread Starter
|
Posting Guru
Joined: Nov 2006
Posts: 1,059
Likes: 0
From: Herndon KY
farmert, and PLC you guys were right on, I pulled the sensor cleaned a little bit of grit off and the problem was solved, thanks for your input.
I always come to this site before I touch anything, and it paid off again.
I always come to this site before I touch anything, and it paid off again.
Thread
Thread Starter
Forum
Replies
Last Post
DieselRugger
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
12
Dec 15, 2022 01:33 AM
bryan_johnson
1987 - 1996 F150 & Larger F-Series Trucks
14
Jun 6, 2004 08:47 PM
