rpms high on highway
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rpms high on highway I'm thinking/hoping this is an electrical/solenoid issue.... on the interstate this morning I accelerated and the rpm's never came back down to lockup as they normally do. I have 3.42's and normally run about 2100-2200 rpms in 4th locked up and about 2600 not locked up. Well, Rpms settle around 3000 after i accelerate and act as if it wants to lock up. But it doesnt.
I've logged through HPT and The trans goes into 1-4 gears on cruise just fine and locks up when it should. On the interstate is only when its not right. Through HPt ive tuned to not lockup in 3rd so would the trans not be locking up in 4th? would this be a 2-4 solenoid issue? my tune has worked like this forever. this is just random. my trans is built. any ideas?
I've logged through HPT and The trans goes into 1-4 gears on cruise just fine and locks up when it should. On the interstate is only when its not right. Through HPt ive tuned to not lockup in 3rd so would the trans not be locking up in 4th? would this be a 2-4 solenoid issue? my tune has worked like this forever. this is just random. my trans is built. any ideas?
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well, I left work and went out and tried it again. I noticed that the trans is showing current gear as 4th via HPT but the trans is still in 3rd. I downshifted out of OD into Drive and confirmed this as RPM's didnt change. everything else is good. I have a Sonnax billet 4th servo. any issues with those?
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From: Portsmouth, VA
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From: Portsmouth, VA
my builder seems to think it's the 4th servo or a pressure valve. I took a spare servo out another trans I have and will give that a try sometime later. the o-ring had to be cut to remove the cover. does anyone have a part # for the O-ring seal?
You have the sonax billet servo , was the gold washer installed and has it ever had a solid feeling fourth gear ?Sorry didnt catch you earlier just now saw the post.
I doubt its a solenoid issue at least as far as the 1-2 and 2-3 solenoids, Now a bad 3-2 solenoid can cause no fourth. But really any solenoid issue should set a code.
I would check the servo but they are not known to cause any problem ,But since you said you fel it go into fourth then slowly come out band pin length or the gold washer missing are prime things to look at .
I doubt its a solenoid issue at least as far as the 1-2 and 2-3 solenoids, Now a bad 3-2 solenoid can cause no fourth. But really any solenoid issue should set a code.
I would check the servo but they are not known to cause any problem ,But since you said you fel it go into fourth then slowly come out band pin length or the gold washer missing are prime things to look at .
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Last edited by performabuilt; Feb 26, 2007 at 06:10 PM.
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From: Portsmouth, VA
my builder also said that it could be that the pressure valve may have some metal in it. (I broke an output shaft a little while back). Ill try the servo then the pressure valve. he doesnt think it's anything major. I'll double check the washer tomorrow whenever I can get under the car to work on it before it gets dark.
yea, no codes.has always shifted great. fluid is fine and still clear as the day I put it in. I'll post updates when they come about. thanks.
yea, no codes.has always shifted great. fluid is fine and still clear as the day I put it in. I'll post updates when they come about. thanks.
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Well a sticky valve is always possible .Not sure how the PR vavle would affect though as it would have and affect on all gears, Serious as far a band or clutch, I doubt it if third is agood and firm since beyond that both 2nd and 4th are the band ,Cheak those things and let me know .
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From: Portsmouth, VA
i put in a new pressure switch and that didnt fix it. still no 4th gear mechanical shift. HP tuners see's that it's in 4th but the trans isnt. we still think that it probably isnt the sonnax servo. could it still be the 3-2 solenoid?
I have the exact same problem in my 02 TrailBlazer. I have EFILive, but it shows 4th gear and TCC slip of like 900-1000rpm!!! 
Not good.
OK, so for the past couple weeks since this really became an issue, Ive been driving around in 3 (Or D, the TB has PNRD321) and on the hwy the TC locks up perfectly and I get <5rpm TCC slip. Shift to D (OD), and it commands 4th gear, and TCC slips at 900-1000rpm. I cant verify if my trans is actually shifting into 4th gear or not, but the rpms do not change at all. Im going in on Monday to the local transmission shop to have them install a TCC Powervalve and a bunch of TCC lockup parts in a special kit they assembled to kill the 1870 Trans slippage code (which I get after extended acceleration/deceleration periods in D [OD]).
I have a Transgo HD2 shift kit, Vette servo, and Superior Billet OD servo. I installed it all myself a little over a year ago, and thats when the problem started. I wonder now after reading this post if my OD servo has finally become loose enough that it is not allowing my trans to shift into 4th gear.
What is the easiest way to check this and adjust it, I would love to not have to drop my trans but would rather spend a couple hours under my truck than spend $500 for the code 1870 fix-it kit.
Not good.OK, so for the past couple weeks since this really became an issue, Ive been driving around in 3 (Or D, the TB has PNRD321) and on the hwy the TC locks up perfectly and I get <5rpm TCC slip. Shift to D (OD), and it commands 4th gear, and TCC slips at 900-1000rpm. I cant verify if my trans is actually shifting into 4th gear or not, but the rpms do not change at all. Im going in on Monday to the local transmission shop to have them install a TCC Powervalve and a bunch of TCC lockup parts in a special kit they assembled to kill the 1870 Trans slippage code (which I get after extended acceleration/deceleration periods in D [OD]).
I have a Transgo HD2 shift kit, Vette servo, and Superior Billet OD servo. I installed it all myself a little over a year ago, and thats when the problem started. I wonder now after reading this post if my OD servo has finally become loose enough that it is not allowing my trans to shift into 4th gear.
What is the easiest way to check this and adjust it, I would love to not have to drop my trans but would rather spend a couple hours under my truck than spend $500 for the code 1870 fix-it kit.