89 tranny problems
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89 tranny problems
Hi everyone! I am new to the site and this is my first time ever owning a Ford truck. I bought an 89 F-150, 4x4, super cab, long bed, 302 (5.0), and what I believe is a c6 transmission. The truck has a 3in. cat. and three inch pipe that dumps before the rear axle.
Anyways enough about that. My problem is that when ever the truck is warmed up to normal operating temperature the trans seems to have trouble shifting into either 2nd or 3rd, not quite sure I am pretty sure it is third though. anyways if I am driving around town any time I leave a stop sign it will shift to 2nd normally and then hold second until I either gun it up to 50 or it just decides to.
When the truck is cold like in the morning, this does not happen.
Any ideas?
Thank you.
Tom
Anyways enough about that. My problem is that when ever the truck is warmed up to normal operating temperature the trans seems to have trouble shifting into either 2nd or 3rd, not quite sure I am pretty sure it is third though. anyways if I am driving around town any time I leave a stop sign it will shift to 2nd normally and then hold second until I either gun it up to 50 or it just decides to.
When the truck is cold like in the morning, this does not happen.
Any ideas?
Thank you.
Tom
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 13
From: Sand Lake, MI
If it is the C6 check the vac line to the modulator valve, make sure it has full engine vacuum supplied to it, its vac line should connect directly to the intake manifold.
Use a hand vac (if you have one) pull the line off the intake and pull a vac on it and see if it holds.
If not, the vac bleeds off in a short time you have a line or modulator leak/problem.
That line changes from rubber to metal and back to rubber again from the factory. One of the rubber sections may be damaged or the metal section may have rusted.
If the vac supply source/line checks good you might want to replace the modulator valve itself, not a expensive part regardless but check the supply to it first.
The symptoms you describe suggest it might be a problem with that system, I'd start there.
Use a hand vac (if you have one) pull the line off the intake and pull a vac on it and see if it holds.
If not, the vac bleeds off in a short time you have a line or modulator leak/problem.
That line changes from rubber to metal and back to rubber again from the factory. One of the rubber sections may be damaged or the metal section may have rusted.
If the vac supply source/line checks good you might want to replace the modulator valve itself, not a expensive part regardless but check the supply to it first.
The symptoms you describe suggest it might be a problem with that system, I'd start there.
