Cant shift into first gear or reverse on Manual Transmission

If your 2007 H3 Hummer suddenly stopped shifting into reverse gear, there could be several potential causes. Some common causes of a sudden loss of reverse gear include a failed reverse gear band, a damaged valve body, or a failed reverse gear solenoid. Additionally, low transmission fluid levels, a clogged transmission filter, or a damaged transmission pan gasket could also prevent the vehicle from shifting into reverse. It is recommended to have a professional mechanic diagnose the issue to determine the exact cause and provide the necessary repairs. They may need to perform diagnostic tests or inspect the transmission to pinpoint the issue.

There could be several reasons why your 2005 Dodge Magnum is experiencing problems with shifting from second to third gear and then suddenly hitting reverse, including:

1. Transmission Fluid Level: Low transmission fluid level can cause erratic shifting, slipping, or stalling in your vehicle. Make sure to check your transmission fluid level and add if necessary.
2. Shift Solenoid: A faulty shift solenoid can cause problems with shifting in your transmission. The solenoids control the flow of transmission fluid through the valve body, which controls the shifting of gears. If the shift solenoid is failing or has failed, it can cause the transmission to slip, shift erratically, or get stuck in a gear.
3. Transmission Pump: The transmission pump is responsible for pumping transmission fluid through the transmission and to the torque converter. If the pump is failing, it may not be able to pump fluid properly, leading to problems with shifting and slippage.
4. Valve Body: The valve body controls the flow of transmission fluid through the transmission and directs the shifting of gears. If the valve body is failing, it can cause the transmission to shift erratically or get stuck in a gear.
5. Transmission Control Module (TCM): The TCM is responsible for controlling the transmission's shifting and overall performance. If the TCM is failing, it can cause the transmission to shift erratically or get stuck in a gear.

It's best to have a qualified mechanic diagnose and repair the issue as they will have the necessary tools and expertise to properly diagnose and fix the issue.

Check the linkage first. They put plastic grommets on the arms. They disintegrate. After that, it is internal. They also put plastic tabs on the shift forks. Could be a bad gear.

Both error codes you have are transmission related. P0736 is an error for reverse has wrong gear ratio. P0700 is a general transmission problem code
http://www.obd-codes.com/p0700
http://www.obd-codes.com/p0736
for more information.

It appears this is a 5 speed manual transmission. There may be shift linkage problems between the shift lever and transmission. also bushings. I strongly recommend a repair manual specificly for this transmission. possibly filespeep.com or manualslib.com
How is the clutch and throwout bearing?

when you put it in reverse,first thing you feel a spring.after tthat you lift,
a security plate,this plate prevent you from going reverse into 1 gear.
cause the axel turn a little further when you allreddy has stop the car.
this takes two sec.thats why when putting it in reverse after you feel the spring you wait two seconds,then puch al the way in reverse.

90 Ford Bronco II: You have to put it in whichever gear you want it in before you start it or it wont shift at all. Then once you are going its extremely hard to shift into the other gears. Reverse is the only gear that sounds like its grinding.

It can be issue with gears or problem with transmission and needs to be rebuilt. Also get the ****** fluid checked. If it's low, then such problems occurs.

To troubleshoot these types of issues, check the actual solved problems with these types of issues.

There are solved help links provided below: -------

Click the link below and go through the details and diagrams to troubleshoot the problem: -----
2003 Lexus RX300: Transmission Fluid Burnt Brown and not Shift to reverse?

http://whatisbyme.blogspot.in/2012/05/2003-lexus-rx300-transmission-fluid.html

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2007 Chrysler 300: Transmission Stuck in Park?

http://repairhelpcenter.blogspot.in/2012/06/2007-chrysler-300-transmission-stuck-in.html

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2000 Toyota Camry: Transmission slipping and Stuck up?

http://whatisbyme.blogspot.in/2012/05/2000-toyota-camry-transmission-slipping.html

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1996 Toyota Corolla: Transmission Shift Interlock will not Release?

http://technoanswers.blogspot.in/2012/04/1996-toyota-corolla-transmission-shift.html

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Lexus LS400: Transmission or Torque Converter?

http://technoanswers.blogspot.in/2012/04/lexus-ls400-transmission-or-torque.html

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CV AXLE stuck in Transmission?

http://technoanswers.blogspot.in/2012/04/cv-axle-stuck-in-transmission.html

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Transmission in reverse, acts like it's in neutral? http://schematicsdiagram.blogspot.in/2012/04/transmission-in-reverse-acts-like-its.html

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Delayed shift and harsh Shifting?

http://schematicsdiagram.blogspot.in/2012/04/delayed-shift-and-harsh-shifting.html

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Dodge neon wont go in reverse?

http://technoanswers.blogspot.in/2012/02/dodge-neon-wont-go-in-reverse.html

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Dodge Automatic transmission will not go into reverse?

http://technoanswers.blogspot.in/2012/02/dodge-automatic-transmission-will-not.html

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Dodge manual transmission will not go in reverse gear?

http://technoanswers.blogspot.in/2012/02/dodge-manual-transmission-will-not-go.html

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Transmission is making buzzing noise?

http://technoanswers.blogspot.in/2012/02/transmission-is-making-buzzing-noise.html

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1998 Dodge Ram: Not Shift To Reverse? http://schematicsdiagram.blogspot.in/2012/06/1998-dodge-ram-not-shift-to-reverse.html

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Transmission leak on Toyota?

http://schematicsdiagram.blogspot.in/2012/02/transmission-leak-on-toyota.html

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Automatic transmission, with no reverse?

http://howtobyme.blogspot.in/2012/02/automatic-transmission-with-no-reverse.html

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No Movement When Transmission is Shifted to Drive or Third?

http://schematicsdiagram.blogspot.in/2012/03/no-movement-when-transmission-is.html

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While going in reverse mode Fuse number 27 blows on Ford Ranger?

http://howtobyme.blogspot.in/2012/02/while-going-in-reverse-mode-fuse-number.html

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These will help.

Thanks.

The shifter needs to be inspected. If The shifter assembly is got misaligned, it has to be open and realign.

There are many other possibilities.

Also i suggest you to refer these gear shift issues, which are mostly noticed. These are direct links with appropriate solutions to the specific problems of gear ****.

GEAR SHIFT ISSUES

Gear indicator Shows "3" Instead Of "D"? http://whoisbyme.blogspot.in/2012/07/gear-indicator-shows-3-instead-of-d.html --------- 2006 Chrysler 300c: Shifter Stuck in Park? http://technoanswers.blogspot.in/2012/06/2006-chrysler-300c-shifter-stuck-in.html ---------- 1998 Ford Expedition: Will not Shift Out of Park? http://schematicsdiagram.blogspot.in/2012/06/1998-ford-expedition-will-not-shift-out.html --------- Car will not move when in gear? http://repairhelpcenter.blogspot.in/2012/02/car-will-not-move-when-in-gear.html ----------- Mercedes-Benz transmission sticks in first gear? http://technoanswers.blogspot.com/2012/01/mercedes-benz-transmission-sticks-in.html ---------- Mercedes Benz not engaging in first gear? http://technoanswers.blogspot.com/2012/01/mercedes-benz-not-engaging-in-first.html ---------- Chrysler PT Cruiser only goes in First gear?

http://howtobyme.blogspot.com/2011/11/chrysler-pt-cruiser-only-goes-in-first.html

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Car is stuck in park and the shift will not move?

http://howtobyme.blogspot.com/2011/08/car-is-stuck-in-park-and-shift-will-not.html
------- 2007 Ford Expedition: How to shift car in neutral with Dead Battery http://www.howtorepairguide.com/2012/11/2007-ford-expedition-how-to-shift-car.html -------- 2002 Nissan sentra will not go out of park mode? http://technoanswers.blogspot.in/2012/02/2002-nissan-sentra-will-not-go-out-of.html -------- Nissan Sentra stuck in park? http://technoanswers.blogspot.in/2012/02/nissan-sentra-stuck-in-park.html --------- Car will not come out of Park?

http://howtobyme.blogspot.com/2011/11/car-will-not-come-out-of-park.html
----------- Automatic transmission will not go into high gear?

http://howtobyme.blogspot.com/2011/11/automatic-transmission-will-not-go-into.html

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Car won't downshift sometimes?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-downshift-sometimes.html
-------- Buick Park Avenue: Transmission will Not shift into drive?

http://schematicsdiagram.blogspot.com/2011/12/buick-park-avenuetransmission-will.html
------------ No First gear Starts In Second Gear http://www.howtobyme.blogspot.com/2012/07/no-first-gear-starts-in-second-gear.html ------- Ford Taurus won't shift from park? http://schematicsdiagram.blogspot.com/2011/12/ford-taurus-wont-shift-from-park.html --------- 2006 Ford F150: Will Not Shift out Of Park? http://technoanswers.blogspot.in/2012/06/2006-ford-f150-will-not-shift-out-of.html -------- Car Transmission will not go into Park mode?

http://schematicsdiagram.blogspot.com/2011/12/car-transmission-will-no-go-into-park.html
---------- 1998 Chrysler Voyager: Transmission Problem? http://howtobyme.blogspot.in/2012/06/1998-chrysler-voyager-transmission.html ------ Shift indicator directly goes to 2nd when key is turned ON?

http://schematicsdiagram.blogspot.com/2011/12/shift-indicator-directly-goes-to-2nd.html
-------- Third gear missing and engine losing power?

http://schematicsdiagram.blogspot.com/2012/01/third-gear-missing-and-engine-losing.html
-------- Chevrolet silverado has whining sound in gear?

http://technoanswers.blogspot.com/2012/01/chevrolet-silverado-has-whining-sound.html
---------- 2002 Chevrolet Avalanche Z71: Gear shift Issue? http://whoisbyme.blogspot.in/2012/06/2002-chevrolet-avalanche-z71-gear-shift.html ---------- Hard to shift gears on Manual transmission?

http://technoanswers.blogspot.com/2012/01/hard-to-shift-gears-on-manual.html
-------- Car hard shift at slow speeds?

http://technoanswers.blogspot.com/2012/01/car-hard-shift-at-slow-speeds.html
--------- Transmission-Hard To Down Shift http://technoanswers.blogspot.in/2012/07/transmission-hard-to-down-shift.html --------- Automatic transmission shift lever hard to move on cold mornings?

http://technoanswers.blogspot.com/2012/01/automatic-transmission-shift-lever-hard.html
------------ 2000 Nissan maxima shifts hard?

http://schematicsdiagram.blogspot.in/2012/02/2000-nissan-maxima-shifts-hard.html

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Vehicle noticed sluggish delayed shifts while driving?

http://schematicsdiagram.blogspot.in/2012/03/vehicle-noticed-sluggish-delayed-shifts.html

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2007 Hyundai Santa Fe: Will not Shift out of Park Mode?

http://schematicsdiagram.blogspot.in/2012/06/2007-hyundai-santa-fe-will-not-shift.html

These details will help.

Thanks.

The seals inside your transmission are bad and leaking by and they don't start to seal until the tranny fluid warms up and swells the seals. To temporarily fix this problem you can pour some brake fluid into your transmission fluid. This will swell the seal in the transmission and it should start working again. This is only a temporary fix however, eventually you will ned to replace or rebuild your tranny. I used this method on a turbo trans 350 and got a year of service out of it that way before I had to replace the tranny. Just do not put too much brake fluid into the tranny, I would recommend one or two capfuls to start with.

Problem is likely either a worn shift fork or bad synchro (both inside the transmission) It's unlikely that you have a clutch problem otherwise the problem would be with first and reverse and shifting other gears would also be difficult.