Hello, I have an older Allegro Star class A motor home, it is a 1996 with the Chevy 454 engine and a 4L80E transmission. The transmission has been rebuilt twice but I seem to be having trouble going up hills, manual says to down shift to third going up hills but when I do I feel it drop out of overdrive, like it should, and when I give it some gas it feels like the transmission is slipping, I let off on the gas and it catches up, by the time I am cresting the hills I have dropped speed to about 40 mph from 65 to 70 mph and on interstates drivers behind me are not happy with me. I am looking for a cure for this, and wonder if it could be in the transmission controller which is the only other thing I could change, any ideas out there?

When was the transmission serviced? Could be a bad solenoid in transmission or a loose connector.What was the reason for rebuilds? How may miles on the rig? How much does it weigh?

There are as few really talented automatic transmission rebuilders as alternator rebuilders.If push-comes-to-gunfire, bite the bullet and go with a genuine Goodwrench Reman.When I saw how they virtually reconstruct a transmission (using things like new improved valve bodies to eliminate porous passage leaks, and clutch drums and shafts that have been heat treated, that sold me, solid. The price is a knee-knocker but worth it. Dealer install costs ar not worth it. Make it a cash n carry.

Don't know about the first rebuild, when I had it done it was because it was slipping much like it is now only more often, it has 40,000 miles, do not know weight for the 29 footer and this is the first trip only about 1,000 miles that is what is pushing me toward the controller, I checked the connections.

MEXICOWANDERER wrote:There are as few really talented automatic transmission rebuilders as alternator rebuilders.If push-comes-to-gunfire, bite the bullet and go with a genuine Goodwrench Reman.When I saw how they virtually reconstruct a transmission (using things like new improved valve bodies to eliminate porous passage leaks, and clutch drums and shafts that have been heat treated, that sold me, solid. The price is a knee-knocker but worth it. Dealer install costs ar not worth it. Make it a cash n carry.You can also look at Jasper, they do similar things, I had to put one in my old 1996 C1500....Something to think about.

The controller is in the ECM. Not many miles and rig should not have a weight problem.I would be checking the connectors on the transmission.Then have the solenoids checked.40,000 miles total on rig? No engine check light?

4L80E transmission problem | Good Sam Community

20 Replies

enblethen
Nomad
Jun 30, 2016
No, it should not rev up. Are you seeing this action on the tach? If not it could be the engine fan coming on because of heat.
Are you trying to do climb at high speed? I let my rig find a comfortable speed and RPM. Some passes are pulled at 3000 RPMs in second or third gear depending on grade.
PaulJ2
Explorer
Jun 30, 2016
enblethen wrote:
In 1993 the converter does not lock up in 3rd.

Thanks enblethen. So then I would say the transmission is likely operating completely normal.
enblethen
Nomad
Jun 30, 2016
In 1993 the converter does not lock up in 3rd.
PaulJ2
Explorer
Jun 30, 2016
When in OD 4th the torque converter is locked. When you manualy shift to third it sounds like the torque unlocks and causes slippage which is normal when unlocked.
My question is-- should the torque converter stay locked in third or not?
Maybe a programing problem.
KJINTF
Explorer
Jun 30, 2016
I will be installing the TRANSGO Reprogramming Kit
in my 2008 4L85E later this summer
The same kit or a similar one fits your tranny
Check out their web site - they know and understand transmissions

Installed a few of the Transgo kits over the years
Jeeps 545RFE and 42RLE
Chevy TH350
All with wonderful results - better shifting and reduced slippage

I believe the 4L80E/4L85E are based on the TH400 - only real down side it that they are 4 speed trannys - Not as good or as heavy as the Allison but good trannys.

Remove the pan and take a look see - change the filter and fluid
enblethen
Nomad
Jun 30, 2016
The controller is in the ECM. Not many miles and rig should not have a weight problem.
I would be checking the connectors on the transmission.
Then have the solenoids checked.
40,000 miles total on rig? No engine check light?
Tachdriver
Explorer
Jun 30, 2016
MEXICOWANDERER wrote:
There are as few really talented automatic transmission rebuilders as alternator rebuilders.

If push-comes-to-gunfire, bite the bullet and go with a genuine Goodwrench Reman.

When I saw how they virtually reconstruct a transmission (using things like new improved valve bodies to eliminate porous passage leaks, and clutch drums and shafts that have been heat treated, that sold me, solid. The price is a knee-knocker but worth it. Dealer install costs ar not worth it. Make it a cash n carry.

You can also look at Jasper, they do similar things, I had to put one in my old 1996 C1500....

Something to think about.
repcola46
Explorer
Jun 29, 2016
Don't know about the first rebuild, when I had it done it was because it was slipping much like it is now only more often, it has 40,000 miles, do not know weight for the 29 footer and this is the first trip only about 1,000 miles that is what is pushing me toward the controller, I checked the connections.
MEXICOWANDERER
Explorer
Jun 29, 2016
There are as few really talented automatic transmission rebuilders as alternator rebuilders.

If push-comes-to-gunfire, bite the bullet and go with a genuine Goodwrench Reman.

When I saw how they virtually reconstruct a transmission (using things like new improved valve bodies to eliminate porous passage leaks, and clutch drums and shafts that have been heat treated, that sold me, solid. The price is a knee-knocker but worth it. Dealer install costs ar not worth it. Make it a cash n carry.
enblethen
Nomad
Jun 29, 2016
When was the transmission serviced?
Could be a bad solenoid in transmission or a loose connector.
What was the reason for rebuilds? How may miles on the rig? How much does it weigh?

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4L80E transmission problem

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