68rfe

[Sethra]

hey! I have a couple questions, Iv been having an issue with my stock 68RFE transmission, After highway driving when the transmission is warmed up past 165 degrees all gears operate flawlessly without any slippage. But if i shift into reverse quickly it will not engage without me revving the engine to around 1500-2000 rpm, However if i shift slowly from drive to neutral then to reverse it will engage. Below 160-165 degrees it will shift into reverse everytime without any special treatment as many times as I need it to. Iv replaced filters, everything is tight, iv air checked the LR clutch and that checks out, Iv replaced the LR tower seal. Iv also noticed when experiencing the issue while in reverse my commanded line pressure is 125pis and my actual will read 100-104psi until i rev the engine and reverse engages then the line pressure will read 124psi.
My CVI’s are as follows
LR: 64
2nd: 46
OD:53
4th: 52
UD:45
So i dont think its a clutch issue. Im kind of leaning toward it possibly being something in the valve body? Possibly the LR clutch accumulator piston seal, and when the fluid heats up it leaks past the seal and has trouble pushing it toward the reverse side until it is revved and line pressure increases. Any ideas ? this has been going on for 2 years lol and im trying to get it figured out

 

[Enve46]

After owning many of these trucks with the 68 I found the best thing to do when shifting to R or D is stop in neutral for a second, then engage. See if that changes anything for you. I would experience something similar when shifting to D to quickly

 

[Dinky503]

hey! I have a couple questions, Iv been having an issue with my stock 68RFE transmission, After highway driving when the transmission is warmed up past 165 degrees all gears operate flawlessly without any slippage. But if i shift into reverse quickly it will not engage without me revving the engine to around 1500-2000 rpm, However if i shift slowly from drive to neutral then to reverse it will engage. Below 160-165 degrees it will shift into reverse everytime without any special treatment as many times as I need it to. Iv replaced filters, everything is tight, iv air checked the LR clutch and that checks out, Iv replaced the LR tower seal. Iv also noticed when experiencing the issue while in reverse my commanded line pressure is 125pis and my actual will read 100-104psi until i rev the engine and reverse engages then the line pressure will read 124psi.
My CVI’s are as follows
LR: 64
2nd: 46
OD:53
4th: 52
UD:45
So i dont think its a clutch issue. Im kind of leaning toward it possibly being something in the valve body? Possibly the LR clutch accumulator piston seal, and when the fluid heats up it leaks past the seal and has trouble pushing it toward the reverse side until it is revved and line pressure increases. Any ideas ? this has been going on for 2 years lol and im trying to get it figured out

What year truck?

 

[609er]

Most likely a valve body issue. Any line pressure codes? When it does engage is it harsh?

 

[Dinky503]

Most likely a valve body issue. Any line pressure codes? When it does engage is it harsh?

The high pressure pump has been going out. I have a 2022 work truck and we did fluid change and pump went out. I've heard of a few others as well.