HELP: Automatic, can move forward. But, cannot reverse.

[lm723]

Helping a friend..

98 Nissan Sentra can move forward. But cannot do a reverse.

Symptoms:
When cold, car can do a reverse - but needs more rev power (mahina na).
When hot, cannot do a reverse, even revving more, wala na.

What could be the problem? if the car can move forward, pero cannot move backward? -- weird.

Thanks

[battcor]

I have this same problem. And same experience as posted here : tsikot_dot_com/forums/transmission-talk-141/1995-nissan-sentra-ss-weak-reverse-84424/

Pa help po. Thanks

[lowslowbenz]

Have you guys tried flushing the ATF and replacing it with new ATF? Do these cars have a transmission filter? If yes, try replacing that along with the ATF flush. Remember that the torque converter should have a drain plug for the ATF too, drain that as well (MB's have them). Valvebody cleaning might also work, but this is best done by a qualified gearbox mechanic. Take note of the ATF appearance when you drain it, and check the bottom of the used oil container for metal particles.

Worse case scenario, reverse brake band and clutches are already worn out, overhaul and replacement is needed.

My 2 cents. Hope this helps.

[battcor]

Have you guys tried flushing the ATF and replacing it with new ATF? Do these cars have a transmission filter? If yes, try replacing that along with the ATF flush. Remember that the torque converter should have a drain plug for the ATF too, drain that as well (MB's have them). Valvebody cleaning might also work, but this is best done by a qualified gearbox mechanic. Take note of the ATF appearance when you drain it, and check the bottom of the used oil container for metal particles.

Worse case scenario, reverse brake band and clutches are already worn out, overhaul and replacement is needed.

My 2 cents. Hope this helps.

I think it has a transmission filter.

I asked my father-in-law to get a mechanic to replace the ATF and will find the result when I get back home later. I will post an update soon.

In case of overhaul and replacement, any idea how much it will cost and any preferred mechanic that can get the work nicely done?

[lowslowbenz]

In case of overhaul and replacement, any idea how much it will cost and any preferred mechanic that can get the work nicely done?

Hi, I'm sorry but I have no idea on how much for parts and labor. Ang alam ko lang is for european brands, and its not cheap.

[yebo]

funny that the least used gear (reverse) ang sira. it could be as simple as a loose wire. pag hindi, planetary gear brake band, or the actuating piston, or solenoid. kung hindi pa din, OH na yan or replace.

di ba nabaha yan? baka hindi na-flush ng husto after flooding kaya nasira ang seals ng pistons ng brake band.

[battcor]

To : lowslowbenz,
Thanks.

funny that the least used gear (reverse) ang sira. it could be as simple as a loose wire. pag hindi, planetary gear brake band, or the actuating piston, or solenoid. kung hindi pa din, OH na yan or replace.

di ba nabaha yan? baka hindi na-flush ng husto after flooding kaya nasira ang seals ng pistons ng brake band.

Yes, nabaha siya noong habagat at baka nga hindi na flushed na mabuti. But I'm still wishing for the not-so-worst-scenario.

Sa mga possible causes you've suggested, simple / mura lang ba ang repair?

Btw, shifting is good and smooth for other gears except lang talaga sa reverse.

[lowslowbenz]

^

The brake bands can be adjusted to specific limits, as in the case of Mercedes Benz. This is done to compensate for wear and tear of the bands due to usage, and is being done by a qualified transmission mechanic. I have no idea if this is possible in a Nissan gearbox, you can ask the opinion of a Nissan casa for this. If the gearbox had water intrusion, chances of rusty/stuck/corroded mechanicals are more likely.

[battcor]

Update: The mechanic was unable to check my car due to large volume of clients visiting his shop.

lowslowbenz, it is nice to hear that it can be adjusted. I hope this can also be done with my car.

We'll keep you posted. Btw, I already bought 4 liters of ATF and will buy one filter.

[yebo]

since nabaha yan most probably seals lang ng piston or rust sa piston area. baka palit lang ng seals ok na. hopefully hindi pa pitted ang sealing area. pacheck mo din wiring harness papunta sa solenoids baka naman rusted lang o poor contact.

[battcor]

yebo, salamat sa mga inputs, gawin ko itong checklist para sa gagawang mekaniko.

Btw, baka may pwede ka irefer na mekaniko here sa pasig or cainta area. :D

Compiling a checklist that may help others with same problem.

- Replace ATF and transmission filter
- Check reverse brake band and clutches for wear and tear
- Check any loose wirings
- Check planetary gear brake band
- Check actuating piston for rust and broken seals
- Adjust brake bands to specific limit
- Check Wiring harness going to solenoid

[lantizx]

*battcor -

I had this issue before and its a headache, i opted to had my transmission overhauled by bulaong, maghapong gawaan at 1yr na okay pa naman yung tranny.

when you replace your ATF, make sure to pulldown the pan see if the filter has residue from the clutchpack. sakin kc ang daming residue then nung na pulldown na yung tranny bakal sa bakal na pala yung mga clutch pack, galing ng nissan nakaka 100 p rin yung auto nung time na sira pa

nga pala ingat sa nag mamarunong gumawa ng tranny, good luck

[battcor]

Update: Mechanic cleaned the valve body including the filter but the problem still persists. Tomorrow he will do an overhaul.

Same situation with you lantizx, the mechanic said that the ATF of my car has so many residues and he thinks they were from broken gaskets.

Based on his way of diagnosing the problem, I think he knows what he is doing ~ I really hope so heheheh :D

I'll try to document the mechanic's solutions:
- Clean transmission filter
- Clean valve body
- Replace ATF

Todo: Overhaul

[lowslowbenz]

That is why I mentioned on checking the old ATF earlier, as it will provide the answers on what is wrong with the gearbox. When assembling the overhauled gearbox, use fresh ATF out of the can. Never skimp on ATF as this is a vital lubricant inside a dry gearbox, and do not re-use the drained (new) ATF as it is now contaminated with debris from the gearbox internals. Lastly, be sure to drain the torque converter of old ATF.

[Retz]

Update: Mechanic cleaned the valve body including the filter but the problem still persists. Tomorrow he will do an overhaul.

Same situation with you lantizx, the mechanic said that the ATF of my car has so many residues and he thinks they were from broken gaskets.

Based on his way of diagnosing the problem, I think he knows what he is doing ~ I really hope so heheheh :D

I'll try to document the mechanic's solutions:
- Clean transmission filter
- Clean valve body
- Replace ATF

Todo: Overhaul

Sir, kindly indicate also actual cost per item.

[battcor]

Noted lowslowbenz, I told the man in charge not to use the drained (new) ATF even though it cost me a total of Php1140.

The next time he replaces the ATF, can he use a lower grade instead?

Btw, his name is Clevi, a mechanic working for Isuzu along Marcos Hi-way near SM Masinag.

[lowslowbenz]

Noted lowslowbenz, I told the man in charge not to use the drained (new) ATF even though it costs me a total of Php1140.

The next time he replaces the ATF, can he use a lower grade instead?

Check your vehicle owners manual for the correct grade of ATF to be used, never downgrade from what is recommended as it will lead to premature gearbox failure (again).

[battcor]

Check your vehicle owners manual for the correct grade of ATF to be used, never downgrade from what is recommended as it will lead to premature gearbox failure (again).

Noted lowslowbenz

[battcor]

Update: I visited the shop this morning and they showed me a quarter-full cup of black components taken from the old ATF.

They will now check the solenoid, clutches, and other components. I gave them Php 2,500 to buy parts that need to be replaced.

I will post the photos soon.

[battcor]

Update: Bad news, need to buy rebuilding kit.

Need your suggestions, should I buy rebuilding kit or should i buy the whole transmission? brand new or not?

Where can I find a store that offers affordable price?

Help!