4l80 Question

[scagle777]

Never owned truck with a 4l80. My last truck had the 4l60 and it was always lazy between 1-2. Never had any problems in 3 years. I notice when driving my HD it seems it wants to hesitate shifting from 3rd to 4th. It only does this when I am on the throttle. It shifts fine when I am driving normal. Is this a problem?

[yukon25008.1]

Ive never noticed that with a 4l80e or 85e, maybe just not looking for it.

whats the mileage?

switch to dex-6

[scagle777]

Ive never noticed that with a 4l80e or 85e, maybe just not looking for it.

whats the mileage?

switch to dex-6

118,000

tranny fluid is pink doesn't smell burnt. It almost seems like the engine when under a load can't make up it's mind if it should stay in third or shif to fourth. When it does shif to 4th it is a firm shift. Doesn't slip.

[yukon25008.1]

I had a post a while back asking guys about tranny additives and everyone kinda said to stick with good synthetic fluid, do the filter and fluid with dex-6, do about 1000 miles than just drain the pan and refill with the new dex-6

[hockeypro1411]

That's why most guys just tow with the tranmission in 3. This excessive shifting under load is what kills transmissions.

[yukon25008.1]

like jake said the less shifting and less heat the better, an upgraded cooler would be an easy inexpensive improvment

[scagle777]

like jake said the less shifting and less heat the better, an upgraded cooler would be an easy inexpensive improvment

I don't tow anything i bought it because it was a good price for a crew cab. I just want to make sure it isn't something I should worry about. I usually take it easy but if I stay on the throttle it seems it doesn't want to shift. It may be normal since it is a heavy duty transmission Im just not familiar with it

[cvandegna]

Prolly some gunk in the valve body - a fluid change may help with that one. The swapping of the stock fin and tube cooler with a stacked plate one is a definite plus, but just driving around town with no load heat shouldn't really be an issue. I can tell you that occasionally I have had my 'puter flip out on me and do really weird things with the shift control - sometimes the lazy shifting you describe, sometimes banging into gear. I've found that shutting it down fully and restarting cures it.

[96chevy7.4L]

What your experiencing with the 4L80E is common. Its due to low line pressure in 3rd gear. Only 80PSI as opposed to 120PSI in 1st and 2nd. A bigger cooler will help. But the absolute fix is a transgo HD2 shift kit. A tune can correct it some degree by increasing the line pressure in 3rd.

[Prokopchuk_9]

What your experiencing with the 4L80E is common. Its due to low line pressure in 3rd gear. Only 80PSI as opposed to 120PSI in 1st and 2nd. A bigger cooler will help. But the absolute fix is a transgo HD2 shift kit. A tune can correct it some degree by increasing the line pressure in 3rd.

 

+1...couldn't have said it better myself.

[[email protected]]

How much does a HD2 shift kit cost - if installed by someone that knows what they are doing?

 

Is this done by simply dropping the pan? If so, while your in there what else might as well be done?

 

 

thanks,

Carl B.

[96chevy7.4L]

Around 120 for the kit and 200 or so for installation. Cheapest place to find the kit is on Ebay they range from 149 to 120 depending on time of year.

[[email protected]]

Around 120 for the kit and 200 or so for installation. Cheapest place to find the kit is on Ebay they range from 149 to 120 depending on time of year.

 

Thank you...

 

Carl B.