Very hard shift between Reverse and Drive (Automatic)

Joined
Feb 16, 2017
Messages
53
Location
Oman -Muscat
I have a 4.7 V8 Series 100 LC.

When you move the shift between Reverse and Drive the whole car is moved as the gears lock in and visa versa. It is a really hard knock and the torque is considerable.

I have checked the transmission box and valve body and I am in the middle of trying to understand why a EC computer seems to report it is in 2nd when really it is in Park and 3rd when in Reverse and 4th when in Neutral. The guys seem to think this is why we get the really hard knock and I am trying to find out why the computer is reporting this error.

Im not convinced as it is very mechanical and suggested something loose. I have checked all UJ's and they are good; although I am not sure how long they can take/suffer this knock.

Any ideas??? Anyone?

I was thinking that the central diff and transfer unit? But cannot think other than play between gears that would contribute to the slack required to create hard exchange between gears.

somebody else has suggested the transmission Control Module but I cannot see this being part of the gear electronics as it does not seem to have a role in gear change.

cheers Chalky
 

DirtDawg

"It'd be alot cooler if you did"
SILVER Star
Joined
Jun 28, 2013
Messages
1,863
Location
Denver, Colorado
For starters, keeping your issue isolated to one thread will help with diagnosing your issue. Separate threads are only going to confuse.

Have you used the FSM to troubleshoot yet? It has some great info in there. Posting reply in other thread.
 
Joined
Feb 16, 2017
Messages
53
Location
Oman -Muscat
Good point well made thanks. Sorry
I have 2 issues
1) computer reading/diagnostics conflict of reading.
2) really hard knock from gear change.

Now if it turns out to be the same issue then great but I was treating one as electrical and one as mechanical.

Sorry it is really bugging me and I am desperate to move forward.
 
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