truck shifts violently at part throttle

[viperbluelx]

I have a buddy with a 95 Lightning with 180K miles, recently it started shifting VERY hard when driving normal at part throttle, but if you run the truck at WOT it seems the tranny actually slips when it shifts. Any ideas?

 

[bumperquip]

First thing I'd start with is a full tranny service with a full fluid purge (about $90 to $95 at a shop).

Then I'd look at replacement of the MLPS (manual lever position sensor). It's about $45 a pretty simple to remove and install.

 

[ROACHCLASS]

My 03' Lightning does this sometimes but other times it doesn't. I'm getting my tranny serviced this week so hopefully that cures it. If not, how much do you think a new trans would run?

 

[bamaRed]

i could be wrong, but on the back of the transmission there is a vacume pump, with a rubber hose, on the passanger side, check and see that hose in on there,
the reason i say that is, i had a problem with a mustang one time, and that hose was off, and it would shift like %it. or, the speed sensor. try checking one of those. hope you get it figured out;,

 

[lightning_2000]

theres a fuse in the fuse panel.. does the miles on the cluster still light up?

could be blown fuse..... take battery cables off for 5 mins and then test drive

 

[John O'Donal]

Sounds like you have a modified valvebody.

if your tranny is having serious troubles, it may go into Failure mod.
the tranny will shift severe, even on mild shifts.

You can reset it by unplugging the battery.
* one cause is a bouncing Speedo. good luck