Auto trans 3rd gear acts like neutral after a briefe let up and back down on the throttle

[forbyin]

Love this group. I've learned more about my pathfinder from you guys than any other forums. My 90 pathfinder se 4x4 auto trans wont stay in 3rd gear if you unload it(lift off of the throttle) at hiway speeds. It acts totally normal at any speed below about 45 mph but over that it goes into free wheel when ever I lift off the gas then get back on it. Engine braking is not effected, just acceleration. I know that the over run clutch pack locks up at 1/16th throttle or less and that is what allows for engine braking in 3rd gear(drive) but what I am having a hard time figuring is what makes the trans refuse to go back to forward 3rd gear under acceleration. I am currently disasembling the trans and havn't found any signs of burnt or broken parts in the clutches or sprags. There is on check ball in the valve body that is has slightly deformed the seperator plate but I have not been able to discern which circuit it controls and if it is normal wear or damage from too much fluid pressure. Since internal trans work is not my specialty, I was hoping somthing similar may have happend to someone reading these forums.

thanks

[nismothunder]

Trannys hosed,get a new one.my 95 did the same thing.Slipping in third and od like wwhat you said,you let off the gas and it slips like there no gear there at all until it'll catch.I still drove mine like this so I lost 3/od and now 2nd is starting to give out.Do a 5 speed swap or swap in a good used tranny and rebuild this one.

[forbyin]

Thanks for the advise. I ordered a rebuild kit, torque conv, sprags, and a modified valve body today from Transtar. Kind of like throwing a hand full of rocks hoping to hit one bird.

Edited September 7, 2010 by forbyin

[Precise1]

Where in NorCal are you?? I have the repair manual for the auto tranny if you want to borrow it to try to fully isolate what the problem parts are...

 

B

[Kingman]

Before you install your new transmission, be sure to add an aftermarket cooler and bypass the factory one. If you don't, you'll more than likely burn up the new transmission.

[forbyin]

"Where in NorCal are you?? I have the repair manual for the auto tranny if you want to borrow it to try to fully isolate what the problem parts are...

 

B"

 

 

 

 

I live in Weaverville, North West of Redding. Thanks for the offer but I have Alldata at the shop. There are a lot of trans related TSBs but nothing with symptoms like mine. Alldata also gives complete overhaul instructions. I am pretty sure that my problem is in the valve body causing the overrun clutches to stay tight, causing the forward sprag to freewheel. Basically the trans is getting stuck in "3rd gear engine braking mode", even when I step back on the throttle. It didn't need a complete over haul to cure this problem, just a valve body, but it gives me peace of mind to know the trans is going to be "fresh" when I'm done.

[Precise1]

Ok, fair enough. You obviously have all the information and far more knowledge of the auto trannys than I do (I have none). Just wanted to offer. Have you considered installing a shift kit??

 

Good luck with everything.

 

B

[forbyin]

Ok, fair enough. You obviously have all the information and far more knowledge of the auto trannys than I do (I have none). Just wanted to offer. Have you considered installing a shift kit??

 

Good luck with everything.

 

B

 

 

The afermarket valve body is modified to address weaknesses in the oe design. Probably a little over kill to replace the whole valve body but I know I'll have a good unit.