Transmission slips/jerks when hot

The Stig · February 27, 2017

Im facing an issue in my BJ5P related to the transmission.

About a month ago on the way to Kandy my transmission started giving trouble. I was driving a bit aggressive and whenever I wanted to accelerate the kick down didn’t take effect smoothly. There was a jerk when the kickdown came and on 2 occasions there was even wheelspin. When I was not hard accelerating still there was gear slip when going up gears, clearly there was a gap and a long engagement time. Also when braking/slowing down there was a noticeable jerk with a clunk sound when gears were downshifting and some wheel lock.
After that I stopped to let the car cool down and the issue was gone so I went on my way. Again after another 30mins the problem came back. I was planning to go on 800km+ journey and didn’t want to risk it so came to Colombo stopping 5,6 times on the way.
First thing I did was change atf (mazda m5) and it seemed that the issue was resolved upto now. I even went on the highway multiple times and there was no problem.
However a week ago I was driving a bit aggressively within Colombo and the issue was back, but mainly slipping on upshifts. Today also the same thing happened in the morning with a bit of hard acceleration stints.
The notable thing is that the issue comes only when there is some strain on the transmission and when it gets hot. There is no delay in engaging gears in the morning like most others have, N to D shift is almost immediate.

Given that slipping when hot is usually a sign of bad ATF im a bit confused as to what to do. Do I change ATF again and fully clean the gearbox and replace filter ? or should I just give to nilwala for repair ?
I am planning to take the car to nilwala but I want a little heads up on what to expect.

Davy · February 27, 2017

Do you have any visible ATF oil leaks under your transmission? Slippage usually occurs when the ATF level is low or if fluid pressure inside the transmission is low. I don't remember if the BJ5P has an ATF dipstick, but if it does, can you check the level and condition of the oil if possible and report back? Was the transmission oil pan removed and cleaned during the oil change?

Another reason maybe because the fluid is overheating. I think the ATF cooler lines go through the radiator on your car and if so, you may want to check if the lines are blocked. How's the general operating temperature of the engine during your aggressive drive? Still mid point and fans kicking in normally?

Just trying to eliminate other causes here before opening up the transmission. What's the mileage of the car BTW?

Edited February 27, 2017 by Davy

Twin Turbo · February 28, 2017

With those symptoms, a simple atf change will not cure all the issues,you'll need to get the transmission inspected by a trained pro before doiing anything,..

By the symptoms, the transmission is in need of a rebuild/replacement.

Edited February 28, 2017 by Twin Turbo

The Stig · February 28, 2017

On 2/27/2017 at 9:57 AM, Davy said:

Do you have any visible ATF oil leaks under your transmission? Slippage usually occurs when the ATF level is low or if fluid pressure inside the transmission is low. I don't remember if the BJ5P has an ATF dipstick, but if it does, can you check the level and condition of the oil if possible and report back? Was the transmission oil pan removed and cleaned during the oil change?

Another reason maybe because the fluid is overheating. I think the ATF cooler lines go through the radiator on your car and if so, you may want to check if the lines are blocked. How's the general operating temperature of the engine during your aggressive drive? Still mid point and fans kicking in normally?

Just trying to eliminate other causes here before opening up the transmission. What's the mileage of the car BTW?

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Thanks Davy

There are no visible leaks and I checked the garage floor also. I checked the dipstick and the level is high, the colour is cherry red, there are no particles and no burn smell so I think we can eliminate the ATF. Transmission oil pan was removed and cleaned and added new filter.

Your overheating theory seems interesting and very plausible. I'm not sure how the cooling happens, will need to slide underneath and see. As for the general heat of the car I have never had any cooling issues, driven 6-7 hour straight with no problems. Fans kick in and heat indicator is slightly below mid point, this is normal for this model AFAIK.

On 2/28/2017 at 2:01 AM, Twin Turbo said:

With those symptoms, a simple atf change will not cure all the issues,you'll need to get the transmission inspected by a trained pro before doiing anything,..

By the symtomds, the transmission is in need of a rebuild/replacement.

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I know but I prefer to have an idea of what to expect before opening it up.

Edited February 28, 2017 by The Stig

Rumesh88 · February 28, 2017

If the pan was removed and cleaned did you get a chance to observe any large and shiny metallic particles accumulated in the pan and/or around the magnets? (Black color greasy particles attached to the magnets are normal. They are due to normal wear and tare but any large chips is a sign of trouble) In fact if you see lot of loose and large particles in the pan that's a sign that the AT box is on its way out. BTW how did you change fluid - with an ATF exchanger or by draining through the cooler lines? I prefer the latter method.

Davy · February 28, 2017

On 2/28/2017 at 4:24 AM, The Stig said:

Thanks Davy

There are no visible leaks and I checked the garage floor also. I checked the dipstick and the level is high, the colour is cherry red, there are no particles and no burn smell so I think we can eliminate the ATF. Transmission oil pan was removed and cleaned and added new filter.

Your overheating theory seems interesting and very plausible. I'm not sure how the cooling happens, will need to slide underneath and see. As for the general heat of the car I have never had any cooling issues, driven 6-7 hour straight with no problems. Fans kick in and heat indicator is slightly below mid point, this is normal for this model AFAIK.

I know but I prefer to have an idea of what to expect before opening it up.

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That oil looks brand new. The oil lines go to the bottom tank of the radiator, you should even be able to see from the top of the engine if you stick your head in a little. Since you have no cooling issues and since the oil looks pretty good, I doubt it's an overheating issue. But checking for a block is pretty easy.

Remove fluid return line from transmission end and place the end of the line into a clean container. We use the return line to eliminate the probability of blocks in the cooler lines as well.
Start engine and idle for about 10 to 15 seconds
Observe fluid flow and check if the amount of fluid pumped out is within specs (you need a workshop manual to get the correct flow rate, but an experienced person should be able to tell just by looking)
Re-connect all hoses and re-fill transmission fluid

The next thing you should probably do is get a fluid pressure test done. You can get the fluid line pressure checked without opening up the transmission. The transmission has one or more test ports onto which you can plug in a pressure gauge and check if the pressure (at idle and full throttle). The readings should be within the manufacturer's specifications. The procedure is pretty straightforward, but I'm not sure if local workshops even do this. Maybe another member reading this can confirm.

Again, what's your current mileage?

The Stig · March 1, 2017

On 2/28/2017 at 8:54 AM, Davy said:

That oil looks brand new. The oil lines go to the bottom tank of the radiator, you should even be able to see from the top of the engine if you stick your head in a little. Since you have no cooling issues and since the oil looks pretty good, I doubt it's an overheating issue. But checking for a block is pretty easy.

Remove fluid return line from transmission end and place the end of the line into a clean container. We use the return line to eliminate the probability of blocks in the cooler lines as well.

Start engine and idle for about 10 to 15 seconds

Observe fluid flow and check if the amount of fluid pumped out is within specs (you need a workshop manual to get the correct flow rate, but an experienced person should be able to tell just by looking)

Re-connect all hoses and re-fill transmission fluid

The next thing you should probably do is get a fluid pressure test done. You can get the fluid line pressure checked without opening up the transmission. The transmission has one or more test ports onto which you can plug in a pressure gauge and check if the pressure (at idle and full throttle). The readings should be within the manufacturer's specifications. The procedure is pretty straightforward, but I'm not sure if local workshops even do this. Maybe another member reading this can confirm.

Again, what's your current mileage?

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Looks like I will have to go hands on.

Sorry, mileage is 156k and there are signs of previous transmission repair (i can see some gasket sealer on the trans)

On 2/28/2017 at 8:21 AM, Rumesh88 said:

If the pan was removed and cleaned did you get a chance to observe any large and shiny metallic particles accumulated in the pan and/or around the magnets? (Black color greasy particles attached to the magnets are normal. They are due to normal wear and tare but any large chips is a sign of trouble) In fact if you see lot of loose and large particles in the pan that's a sign that the AT box is on its way out. BTW how did you change fluid - with an ATF exchanger or by draining through the cooler lines? I prefer the latter method.

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Atf was drained through cooler lines. Unfortunately i was not there when it was done. After the issue I left this car with the mech, gave oil and filter and went on my journey again. But I'm sure if there were big particles my mech would tell me. He didn't indicate any issues, I will double check just in case.

Btw twin turbo recommended to use some transmission treatment. I will give it a shot, x-1r is avail here. Any experience?

The Stig · March 13, 2017

Update

So I added some ##### transmission treatment about a week ago. So far issue seems to be okay.

My theory is that the clutch packs are worn and the older Atf ketpt it from slipping since it would have been thicker with the worn out material.

Twin Turbo · March 13, 2017

Hope the fix works till you figure out a permanent repair,..

Edited March 13, 2017 by Twin Turbo

harshansenadhir · March 14, 2017

On 3/13/2017 at 7:02 AM, The Stig said:

Update

So I added some ##### transmission treatment about a week ago. So far issue seems to be okay.

My theory is that the clutch packs are worn and the older Atf ketpt it from slipping since it would have been thicker with the worn out material.

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Glad it sorted. Tried this on CE-90 (XADO Revitalizant EX 120 Automatic Transmissions Tiptronic, Steptronic, CVT) from ebay and lasted about 6 months before giving up the reverse gear. Overhaul with oil costed me only 32K and it came with 1 year warranty.

On a side note, clutch plates inside the auto tranny are suppose to be dry and no oil goes in there isn't it?

The Stig · March 15, 2017

On 3/14/2017 at 2:38 AM, harshansenadhir said:

Glad it sorted. Tried this on CE-90 (XADO Revitalizant EX 120 Automatic Transmissions Tiptronic, Steptronic, CVT) from ebay and lasted about 6 months before giving up the reverse gear. Overhaul with oil costed me only 32K and it came with 1 year warranty.

On a side note, clutch plates inside the auto tranny are suppose to be dry and no oil goes in there isn't it?

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I thought they had wet clutches, anyways my transmission knowledge is very limited.

I just came to that conclusion from this

I will need to do an overhaul, just buying some time since I need the car these days badly.

simpleone · March 17, 2017

I second the overhaul option. Cold slipping happened to me on BJ5P and first it was fixed by ATF replacement with valve body cleaning. Few months later I had to go for overhaul because different gears started slipping. Particularly the 3rd.

Ezu · April 7, 2017

Guys need a help,my car is MAZDA BJ5W,need to change gear oil(AFT MV)can anyone tell me a place to buy & the price?

Rumesh88 · April 8, 2017

On 4/7/2017 at 11:47 AM, Ezu said:

Guys need a help,my car is MAZDA BJ5W,need to change gear oil(AFT MV)can anyone tell me a place to buy & the price?

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If you took time to use the forum search function you could have ended up with threads similar to the one given below with many discussions on the subject.

http://forum.autolanka.com/topic/18349-mazda-demio-2009-gear-box-oil-change/