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Transmission vacuum line

Will not go into gear

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I have a 1995 Chevy S10 Blazer and have dropped 3rd gear in the transmission. 3rd gear seems like it is in neutral and from time to time you can hear a rattling noise that seems to be coming from the...

Vacuum Reservoir-- I think that is your Evap
Canister,nothing to do with the trans

Pull the trans & rebuild it ,it is done,worn out

No vacuum hose on that trans-- is there

Not been under there to look

Nov 02, 2014 | Cars & Trucks

1 Answer

My 1985 scottsdale 3/4 4x4 has no power in 3rd gear and will not down shift

check to make sure you have no vacuum leaks. u can use a cheap can of carburator cleaner and spray around the vacuum lines of the truck, if your truck starts idling up and changing, you have a leak then just replace the line. Older GM vehicles rely on Vacuum advances for the transmission and will not shift properly nor downshift if there is a leak. a lot of vehicles rely on vacuum to support many functions, mainly driveability as well as smooth running. there should be a vacuum line that runs near the rear of the transmission. also might want to check transmission fluid for the no power, cause even though you may have power in 1st and 2nd, 3rd gear is your main drive gear unless you have a 700R4 with automatic overdrive and it could be suffering from not enough fluid getting to the bands from the pump. also one more thing, check the downshift linkage cable the runs from the carburator to the transmission, make sure it is working, sometimes you can have a broken cable in the line and not even know it. hope this helps

Apr 07, 2014 | 1989 GMC K1500

2 Answers


are there any codes? have you check the fluid level? what type of transmission fluid did you put in?

Jan 27, 2013 | 1999 Chevrolet Silverado 1500

1 Answer

Transmission doesn't want to go into 3 without manaully shifting into 2 gear

Check the transmission fluid level, by the book, usually with the motor running in park or neutral, find out which one.
If that's ok, start looking for a bad vacuum line or connection. Any vacuum leak can throw off the transmission shifting. Try to pull each connection off, if it comes off easy, check to see if it is split or swollen. My Ford uses hard plastic vacuum lines, they break.

Mar 16, 2012 | Cars & Trucks

1 Answer

Transmission is fixed, has a new TPS and a new Oxygen sensor. After these last 2 things was install (past sunday). Vehicle now doesn't sound too accellerated but I still continue having problems with the...

Dont throw it off a cliff just yet :-) Just check the vacuum line from the inlet manifold back to the transmission, ensure that fittings are air tight and that there are no holes in the line.
Explanation for possible fix:- When the car is at idle the inlet manifold plenum has a reasonably high vacuum generated within it. The vacuum line to the transmission conveys this drop in pressure to the shift solenoid. When you accelerate slowly you hardly open the throttle and the vacuum remains high in the system. The solenoid allows early shifts through to the higher gears. If you accelerat hard the throttle is open wide and hardly any vacuum is maintained. The shift solenoid, in the absence of vacuum in the line, now holds each gear for much longer allowing the engine to use its full power band.
If the inlet plenum suffers from an air leak or the vacuum line to the transmission becomes loose or a leak develops in it the solenoid reads this as if the car is accelerating hard and wants to hold each gear for as long as possible. This situation sounds like your problem so check that everything is free of any possible leak. If you find a leak and cure it not only will the shift pattern be fixed but your engine idle will be much better too.

Mar 02, 2011 | 1997 Isuzu Trooper

1 Answer

We a vac line on the top of the tranny.cant find where to attached it. the new motor is reall hard to pops and smells like it flooding. it came with the trotle body on the motor should i replace...

The pops and the disconnected vac(uum) line and the smell of fuel may al be related. The vacuum line to the auto transmission is there to tell that gear shift about the level of load that the engine is under. When you first start the car and accelerate really slowly notice how quickly the gear box shifts up through the gears. However if you accelerate hard the transmission holds each gear for a long time to take advantage of the high power delivered by the high engine speed. The vacuum line conveys to the transmission the level of vacuum in the inlet plenum manifold. When you accelerate slowly the throttle plates only opens a small amount and maintains a strong vacuum level. This vacuum permits the transmission to shift up through the gears quickly. If hard acceleration is demanded the throttle plate is fully open and there is almost no vacuum. The lack of vacuum on the transmission restricts gear shifts. The vacuum lie usually makes connection with the transmission on the left (facing towards the front of the car) near the selector switch. The other end of this line must make connection with a port on the inlet manifold plenum or runner (on my car the port connection is actually very close to the injector on the inlet runner towards the back of the engine). The open connection port is causing the other problems. With un-metered air entering the plenum (not passing through the throttle) the engine computer is struggling to keep the injection times long enough to keep the fuel to air mix balanced. This gives rise to very uneven running and perhaps the 'pops' and smell of fuel that you are experiencing. Locate the connection and stick the vacuum line from the transmission on it. Make sure that there no further leaks compromising the inlet vacuum. Make sure the interior of your 'new' throttle is very clean. All of these things help and add up to a better running engine.

Sep 21, 2010 | Dodge Dakota Cars & Trucks

1 Answer

I'm having trouble when I put the car in drive it's going through it's gear progression slow and it's idiling high I'm thinking it may be the transmission fillter since I had the transmission replaced...

Check this first. On the transmission there should be a small vacuum line that goes all the way to the inlet plenum, check that both ends of this line are are connected securely and that the line has no holes in it. This vacuum line governs the rate at which the transmission moves from one gear to the next. When the engine is running slowly, just above idle, the throttle plate is all but closed and the car will shift through the gears pretty quickly as there is no load and plenty of vacuum. If on the other hand when the engine is racing under load, with the throttle plate fully open, there is little vacuum and the transmission holds in gear for very much longer before up shifting. If this vacuum line is disconnected or leaking the transmission will interpret this as the engine under load and will be very tardy in up shifting.

Sep 08, 2010 | 1992 Buick LeSabre

1 Answer

I have a 1979 350 tran that sliped out of drive at 110 kph and only have low now can you give me a hint on wich way to start with it

The cause for that could be a low transmission fluid level, a faulty vacuum modulator or no vacuum to the vacuum modulator, A faulty front pump assembly or torque converter, a loose valve body or a blown out valve body gasket, the forward or direct clutch pack has lost line pressure to the clutch pack (could be a plugged up transmission filter) or the frictions are burned up in that clutch pack, or the governor has malfunctioned, usually due to missing or stuck governor weights, or a stuck valve inside of the governor, a small plugged up line filter inside the governor fluid channel under the valve body, and most commonly because of a plastic drive gear at the end of the governor that can crack apart or will have sheared off teeth on the drive gear.

Check the transmission fluid level and inspect the vacuum line to the vacuum modulator for any damage and there should be full intake manifold vacuum to the vacuum modulator. Remove the vacuum line at the vacuum modulator and if transmission fluid drips from out of the vacuum line then the vacuum modulator is faulty and should be replaced to eliminate it as the problem, however there might still be a problem with the governor, the valve body, the forward clutch pack, or the torque converter and front pump assembly.

The valve body can be tightened down and the transmission fluid filter can be replaced, and the valve body and the spacer plate gaskets can be carefully replaced, and also inspect for a small inline screen filter inside of the governor fluid feed chanel if the valve body is removed. (there will be check-balls only experienced mechanics should attempt it).

The torque converter, the front pump assembly, and the forward clutch pack can only be repaired by removing the transmission and except for the torque converter dis-assembling the transmission.

The governor can be removed without too much difficulty and the plastic drive gear should be inspected for any damage to the teeth on the governor drive gear and also the worm gear on the output shaft inside of the governor housing that drives the governor gear. Also check the governor or for any missing or stuck weights on the governor or for a stuck valve inside of the governor.

To remove the governor from the transmission remove the clip over the governor cover and then pry the governor cover off, then the governor will pull straight out of the governor housing. (The transmission cross-member might have to be removed on some vehicles to lower the transmission enough to remove the governor)

Here are some images to help assist you inspect the governor, and let me know if you require any further assistance.




Aug 04, 2010 | Chevrolet Cargo Cars & Trucks

2 Answers

Transmission does not shift out of 1st gear automatically. must get off gas for rpms to drop and then it will shift to 2nd gear. no other shifting issues.

There is a vacuum line that is connected to a vacuum modulator on the transmission. The vacuum modulator looks like a tiny inline fuel filter on the right rear of the transmission. Remove the vacuum line from the modulator, if transmission fluid spills out when the rubber hose is removed the modulator is punctured. The engine will **** your transmission fluid through the vacuum line and into the intake system and burn it through combustion. If the modulator is punctured you must have it replaced.

Nov 29, 2009 | 1992 Ford Explorer

1 Answer

When I drive slow or faster than 80K my gear stays on Gear one (I have automatic gear) and I am getting a loud noise from my engine and I tooked to a repair shop by he said he can't do it only Chrysler....

Sounds like a vacuum line. There is a vacuum line that goes to the transmission to tell it when to shift. If it has a PCM, I would suspect that because it tells the transmission when to shift to the next gear. But if you smell gas, you might have a vacuum problem.

Oct 26, 2009 | 1996 Chrysler Town & Country

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