# auto trans slip... ATF pump maybe? **URL:** \ **Category:** Canada Nissan Automotive\ **Created:** [June 6, 2007, 10:51am UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019 "2007-06-06T10:51:12Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![BlackLabeL](https://avatars.discourse-cdn.com/v4/letter/b/439d5e/32.png) [@BlackLabeL](https://forums.speedlife.net/u/BlackLabeL)\ **Post date:** [June 6, 2007, 10:51am UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019/1 "2007-06-06T10:51:12Z")
its on my 91 ka24de auto 240sx. while crusing at highway speeds (80km - 120+km) and with overdrive ON the engine rpm will suddenly go up about 300-500rpm and drop back to where it was. its not as signifigant jump as when i shift out of overdrive, so i know its not changing gears, it must be slipping. at usualy happens when im driving with steady pressure on the accelerator, happens on flat ground happens cold/warm/hot trans fluid was flushed about 1 year ago. fluid level is OK the trans also shifts hard through every gear all the time. im thinking could be a oil pressure related problem, or maybe torque converter problem? any insight would be helpful. ---
**Author:** ![RS13](https://avatars.discourse-cdn.com/v4/letter/r/46a35a/32.png) [@RS13](https://forums.speedlife.net/u/RS13)\ **Post date:** [June 6, 2007, 12:15pm UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019/2 "2007-06-06T12:15:41Z")
torque converter to me. It sounds like its locking and unlocking on the highway ---
**Author:** ![BlackLabeL](https://avatars.discourse-cdn.com/v4/letter/b/439d5e/32.png) [@BlackLabeL](https://forums.speedlife.net/u/BlackLabeL)\ **Post date:** [June 7, 2007, 10:06am UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019/3 "2007-06-07T10:06:52Z")
thats what im thinking. but the torque converter locking and unlocking is controlled by the pressure in the trans fluid, right? so maybe im loosing fluid pressure which is causing the torque converter to slip. anyone know if its an internal/external fluid pump? anyone ever replaced one of these? ---
**Author:** ![CA18DET-180SX](https://avatars.discourse-cdn.com/v4/letter/c/e0b2c6/32.png) [@CA18DET-180SX](https://forums.speedlife.net/u/CA18DET-180SX)\ **Post date:** [June 7, 2007, 11:40am UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019/4 "2007-06-07T11:40:27Z")
The pump would be located directly behind the torque converter. I’ve ripped them out of old chevy trannies. They’re not too bad, I dunno whats all involved in a Nissan one though, won’t be too much different. ---
**Author:** ![Last\_Fuse](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/last_fuse/32/5847_2.png) [@Last\_Fuse](https://forums.speedlife.net/u/Last_Fuse)\ **Post date:** [June 8, 2007, 10:41pm UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019/5 "2007-06-08T22:41:58Z")
Heh, It’s your torque converter. I had the same before my Transmission let loose and killed itself. The hard shifts will cause wear on the planetary gear sets (ie. the gears for 1,2 and D) and like to chip off. Then again if she starts lurching or shaking when this happens just pull her over and stop. I didn’t (tried to make the 3 km home) and the chips blew all my gears and killed my pump. Just a word of warning, so find yourself a nice 5 speed swap. However I had a year before she finally died. Also, do you run Synthetic Trans fluid (wondering if it causes premature wear in Nissan Auto Trans). ---
**Author:** ![Apexi240](https://avatars.discourse-cdn.com/v4/letter/a/e9c0ed/32.png) [@Apexi240](https://forums.speedlife.net/u/Apexi240)\ **Post date:** [June 11, 2007, 4:24pm UTC](https://forums.speedlife.net/t/auto-trans-slip-atf-pump-maybe/147019/6 "2007-06-11T16:24:28Z")
The stator in your torque converter is seized. Time for a new one…