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a little help?

UR LOSN

UR LOSN

New member
been going on now for the past month....since it REALLY got cold...-10 or so.

when I am cruising home...it will hold steady at 2K Rpms....it wont go into OD. I can see it shift into 4th.......but at 55 or so ....I can feel it shift into OD for a split second..then it kicks it out into 4th. I have to be going 65+ for the OD to really work and stay kicked in. I have found out that this may be the reason behind all my fuel consumption. its not staying in low RPm's one might say. it is a vacuum 4L60...

tranny man? 97 GP GT, 156,004 miles on it. no shift kit yet....:o

what would one do?
 


Are you sure it isnt going into 4th OR is TCC not staying applied? TCC is a pretty common problem on these transmissions with higher mileage, especially after warmed up on a good drive on the highway. If you have a scan tool drive it down the road and see what current and commanded gears are and also watch TCC duty% and rpm slippage. If the TCC rpm slippage is higher than 200-250 for a certain amount of time the pcm dissables 4th gear and you will only have 3rd as a top gear until you cycle the key.
 
no codes other than the dang EGR at top end of 2nd.........

Trannyman, I will scan it here this week. I only work 4miles away from my house...so it is a very little drive and the trans is not yet warm.....when I notice this. the engine is barely at 150 when I get to work.

on long trips on the highway...it acts fine...just around town it pulls it out of gear slips then it fels like it finds another gear.

I wish the rpms would stay around 1500 or so...but for around town driving they have been satying 2K and above...
 
I can give you a little knowledge that might help you out.
The 4t60e is a 4 speed transmission with a pulse width modulated lock up.
Overdrive is 4th gear in these units, so I'm assuming you mean 3rd gear when you refer to 4th. Now this is true that if your t.c.c is acting up it will in turn disable overdrive( 4th gear) reason being is overdrive creates a lot of heat and if lock up isn't working correctly to stop the torque converter from slipping it will create too much heat for the trans to handle. It's basically a safety mechanism to save you from expensive trans reapair, but it is usually ingnored since you can still drive it. In order to fix this problem properlly it requires removal of the valve body, which basically means pulling the transmission. The transgo shift kit does a great job of fixing this transmission, but usually your trans is toast when you realize your trans is having problems. Your lucky if you get 80k out of these trannies in your grand prix. They can be very reliable transmissions with a little help so don't be too discouraged.
 
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