4l60e almost perfect

[dangileri]

hey guys i dont remeber if this was asked before but what all senors are directly related to the transmission? the reason i ask, my truck computer raises the line pressure when in park or nuetral, it raises when the rpm raise, as it idles around 900 in park and 600 in gear. putting it in gear, warm or cold, the truck hits as if im neutral dropping it, even though im not on the gas. ive tolerated it for awhile, but my girl has a bad back and the jump is annoying her. i can make it not jump as much is i put my brake to the floor when shifting it, but i can hear the rear start to try and spin and the breaks hold it. any ideas? the tranny has a shift kit and vett servos, etc. but it did this before the rebuild. the engine isnt original to the truck, it was a v6 and someone swapped in a 5.0 and did all new sensors when they did it, around 80k ago. any help is appreciated. and sorry for the horrible spelling, itm typing this in a rush

 

[Tripp]

This is hard to read.

 

[dangileri]

My truck jumps when put in drive or reverse yet all my mounts are solid. It feels like its neutral dropping. Any ideas if it could be a sensor or my computer?


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[poncho62]

How are your "U" joints?

 

[TylerZ281500]

it jumps meaning what? mine lurches forward into gear thats common

 

[dangileri]

Lurches sounds pretty accurate, but its harder then a regular lurche. It hits hard, hard enough to spill a drink. Feels like a little car hit you at 5 mph hard. And i beleive my u joints are fine- they were changed when the tranny was rebuilt as preventative maintence (really i had extra on a shelf-
They were the wrong size for another project but
Fit this fine


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[dangileri]

So just double checked underneath- its all tight but when you put it in gear the driveshaft starts to spin only to take up the slack in the rear, which then starts to spin the axles until the rear brakes hold it


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[Scrufdog]

when you swapped engines did you get a new tune for your computer? Sounds like line pressures are too high, or the Garage Shift settings in the computer are set to hard.

Could also be a worn rear diff, something with the torque converter.

May also be the idle RPM. Most TBI V8's have a desired idle of 700 in P/N (warmed up) and 525 RPM in gear (warmed up).

 

[TylerZ281500]

your pinion shouldnt be loading all that much, it should only have a bit of slack in it, if your turning a half turn of the driveshaft while going into gear that could be your issue that your pinon gear or ring gear is starting to strip out or something, otherwise im with scruff on this one. sounds like your line pressure is too high or your idle is too high and its trying to force the truck to move. has anyone messed with the idle screw on your tbi at all the one that isnt suppose to be messed with?

 

[Scrufdog]

I'm leaning towards a combination of line pressure issues and worn diff. Both my trucks have custom tunes that increase line pressure and change shift characteristics, but neither has a hard shift like you're describing. You might wanna try to get a datalog of your IAC counts/position. Should be around 10-15 warmed up. If its 0, then the idle screw needs to be turned out so that the computer can get the idle lower.