4L60e slips when hot.

[ZANJO]

I have a 97 gmc suburban 5.7L. W/the 4L60e trans. The other day noticed harder shifts into 2nd. Then a day or so later it started acting like it was a misfire with slip and no rev. got it back to a parking lot checked fluid was old but full. No leaks. It sat for a day i get in and rev. Works,drive the whole 9. Will a trans. Filter and fluid help or just throw a used in it? Sure would love some good advice. Thanks.

 

[NickTransmissions]

I have a 97 gmc suburban 5.7L. W/the 4L60e trans. The other day noticed harder shifts into 2nd. Then a day or so later it started acting like it was a misfire with slip and no rev. got it back to a parking lot checked fluid was old but full. No leaks. It sat for a day i get in and rev. Works,drive the whole 9. Will a trans. Filter and fluid help or just throw a used in it? Sure would love some good advice. Thanks.

Are you slipping when shifting into 3rd gear?

 

[ZANJO]

Slips while in 3rd. Once it warms up.and no rev. Once hot too. But cold works fine. Don't know how long since i have'nt tried it on the road yet. But if i sit for awhile it will get me back just slowly...15-20 mph.

 

[NickTransmissions]

Slips while in 3rd. Once it warms up.and no rev. Once hot too. But cold works fine. Don't know how long since i have'nt tried it on the road yet. But if i sit for awhile it will get me back just slowly...15-20 mph.

Time to pull and overhaul it.

 

[Nad_Yvalhosert]

I "second" what @NickTransmissions says.
That's exactly the symptoms of worn out clutch packs. The 4L60 in my Yukon said bye-bye the same way.

 

[ZANJO]

Thanks guys, i'm having a used with 109k installed next week. Crossing my fingers and toes. Not spending 2,500-3,000 for a rebuilt. Can't. And recommendations on the used install? Flush don't flush? just fill with a new filter? I.d.k

 

[NickTransmissions]

Thanks guys, i'm having a used with 109k installed next week. Crossing my fingers and toes. Not spending 2,500-3,000 for a rebuilt. Can't. And recommendations on the used install? Flush don't flush? just fill with a new filter? I.d.k

Before installation, I'd remove the pan so you can see what's at the bottom - that more than anything will indicate whether or not it's functional or has problems. Then change the filter, ohm the solenoids and install a Transgo SK4L60E shift kit along with a Sonnax 4L60E LB1 boost valve.

Hydraulic corrections and improvements will help the unit last longer and perform as you expect.

Lastly, install a NEW torque converter - don't reuse an old one, who knows how much contaminants are inside of it.

You're doing the installation?

ETA: Flush your cooler lines and transmission cooler! Ensure you remove all crud from the system. Otherwise, gunk/burnt clutch material may partially or fully restrict return charge and destroy the rear gear train...

 

[ZANJO]

I am not doing the install, the shop i hired says they will check the pan and do a hot flush as well as a additive called lube gaurd anti shutter.

 

[NickTransmissions]

I am not doing the install, the shop i hired says they will check the pan and do a hot flush as well as a additive called lube gaurd anti shutter.

Keep your fingers crossed. Hope it works.