Slow 1-2 shift

[SnowDrifter]

When hot(155+ trans temp) under light throttle, my 4l60e has a slow 1-2 shift. Feels closer to stock, but I have a corvette servo and tuner in thee specifically to firm up the shifts

It doesn't slip, doesn't flare. All other gears Behave normally. The transmission functions normally whe cold, nice quick shifts. The same if I'm on the throttle to where the trans shifts above 2300rpm.

I've verified fluid level and condition. Replaced the trans filter at 115k. Truck has 130k on it now. Couldn't tell you how long the issue has been going on or if it's a new nevelopmemt as I've only recently been driving in stop and go that brings the trans Temps up that high, with driving conditions that allow me to notice it


I really don't have any experience with transmission stuff. Where would I even begin to look?

 

[swathdiver]

Any internal transmission codes? The normal HOT operating temp is 180-200 degrees, this is the temperature range when checking the dipstick.

A quick look at my shop manual says this slow 1-2 can be caused by low fluid level, low fluid temperature. It also says to check for the actual engine idle speed compared with the desired idle speed and the commanded high PC solenoid current with the actual reading.

 

[SnowDrifter]

Fluid level is normal. Trans doesn't really get hotter than that

No trams codes

Idle in gear is approx 550 to 600rpm

Idle on park or neutral is 1100 by my choice

 

[inmypassatlife]

Replace accumulators

 

[SnowDrifter]

Reckon they're leaky?

Any definitive test or is it a test and check type gig?

 

[swathdiver]

Any definitive test or is it a test and check type gig?

There are tests that can be run with a Tech2.

 

[SnowDrifter]

Which I don't own or have access to. Awesome




Well, at least pricing out OE parts, just parts cannoning is cheaper than getting a diag at the local dealer. Worth the risk I reckon.


OE? Or after market? And if aftermarket, who? Goal is to be on the upper side of shift firmness without crossing into the jerky or hard shifting territory.

 

[SnowDrifter]

After some poking around, seems that Sonnax might be a good choice. The pinless conversion bit though... Uhh... Can someone make my skin stop crawling? The thought of driving a ball bearing into my transmission just makes me itchy all over

 

[inmypassatlife]

After some poking around, seems that Sonnax might be a good choice. The pinless conversion bit though... Uhh... Can someone make my skin stop crawling? The thought of driving a ball bearing into my transmission just makes me itchy all over

how did it go?

 

[SnowDrifter]

Haven't gotten the chance yet

 

[afpj]

Only goes up to 155F on your transmission temp? Dang that's freezing.. when it was like 119 here 2 weeks ago, at stop lights my coolant temp got up to 217, trans temp to 208. 02 yuk 4x4 Carrying 5 people, no luggage, 5.3FF, tow package with stock tranny cooler, no oil cooler.
Sorry, I'm just amazed at how low your "high" trans temp is.

 

[SnowDrifter]

Not really sure what to say. Was 105 to 111 here. Drove 6 hours. Didn't see above 165 trans temp or 210 coolant temp. Hottest I've ever seen my coolant was 214 towing on a hot day in overdrive. Dropped to third and it settled back to 207. Stop lights it creeps to 209

 

[SnowDrifter]

Ok. So. You ever feel like an idiot?

I double checked the owners manual, which specs that the fluid be checked at a transmission temperature of 180-200 degrees. While my fluid was "full" when I checked it, after warming the transmission (putting it in drive and mashing gas and brake) it was overfilled.

Corrected the fluid level and the shift quality seems a fair bit better across the board. RTFM....

In other news, I'm still kicking around that sonnax kit. Has anyone used it? The thought of driving a bearing into a hole in my transmission still gives me the heebie jeebies but after thinking about it, it seems the best route to go as far as reliability is concerned. Need to drop the pan soon anyway to get to the filter so I have the perfect excuse to get in there