Another 4l60e bites it

[RDF1]

Curious how you came to that conclusion? The way I understand it, the 3-4 pack stays engaged in both and the band comes on in 3rd to make OD happen. Unsure if that overruns something or if something must disengage to engage 4th.

Hum... I must have misunderstood the diagram..
Lemme find my manual and make sure I'm not just completely off my rocker.....


Sent from my HiDiNg PlAcE

 

[UGLYTRUK]

Interesting reading.

 

[UGLYTRUK]

I get doses of Sanity from these forums. Thank you

 

[David Barry]

Never done a transmission. Would love to try one. You tube videos seem simple enough. But alas time is not on my side


Sent from my iPhone using Tapatalk

Not sure if this is of any help.

Sonnax

4L60-E, 4L65-E, 4L70-E
TCC Regulator & Isolator Valve Kit
Part No. 77754-03K
Fits '97-earlier Non-EC3 units only
In GM 4L60-E, 4L65-E and 4L70-E unit, severe wear of the TCC regulator valve bore is caused by oscillation of the OE valve allows regulated converter apply pressure to exhaust. This is a primary cause for TCC-related slip code P1870 and overheated converters. Exhausting apply pressure also diminishes line pressure, which can result in burnt clutches. Excess wear at the isolator valve bore reduces TCC apply pressure.

Reconditioning the bore and installing Sonnax TCC regulator and isolator valve kit 77754-03K restores normal TCC operation by shoring up the hydraulic integrity of this circuit.

• 10% Higher apply pressure
  
  
• Isolator valve lengthened to operate in unworn portions of the bore
  
  
• Sleeve manufactured from highly wear-resistant aluminum
  
  
• Hardcoat anodized aluminum valves combat premature wear
  
  
• Annular grooves help center valves in bore to reduce future side-load wear
  

Contents

• Isolator Valve
  
  
• Spring
  
  
• Regulator Valve
  
  
• Regulator Sleeve
  

Symptoms:

• Code 894, 1870
  
  
• Overheated converter
  
  
• Low TCC apply pressure
  
  
• 3-4 Clutch burned
  
  
• 1-2 Harsh
  
  
• Low line pressure
  

Cause:
Excess wear at TCC regulator/isolator valve bore allows TCC apply pressure to exhaust.

Correction:
Recover hydraulic control and renew TCC performance by reconditioning the bore and installing Sonnax TCC regulator and isolator valve kit.

 

[UGLYTRUK]

An interesting side note, is that Sonnax is located in Bellows Falls Vermont, not exactly the place you'd expect a machine shop style of business to be running, you you'd expect it to be in Ohio or Michigan, former manufacturing hubs of the country. It's also owned by Berkshire Hathaway, which is controlled by one man. One of the wealthiest men in the world, Warren Buffet, he usually sticks with food companies. He also owns GEICO and a lot of Kraft-Heinz (47%), you know the ketchup cheese and soup company? According to Wikipedia, he's also the biggest financial services company in the world. How did he end up with a transmission company? Maybe he had trouble with a transmission and he says "I'll fix that, I'll buy a trans company".