TC issue

[limp]

Hello ladies and gentles
It’s me again in this very old thread but very helpful and informative, the mod is working very well no codes whatsoever and I have to says I’m very happy with how it’s running except I have a very small issue when I hit 2000rpms the rpms are dropping almost to 1500rpms then up again it’s doing the same at 3000rpm, I have too say that this issue didn’t start after the mod it has been there since I bought the van. is this normal or not? Your help will be appreciated like always.
Regards
Simon

 

[ajlsl600]

Sounds odd if it's not cogging up a gear at same time. Suggest you look see if any fault codes present. Go from there

 

[limp]

Sounds odd if it's not cogging up a gear at same time. Suggest you look see if any fault codes present. Go from there

Thanks for the reply, it doesn’t really affect the speed or cog the gear other than the engine sound changes for second. I have zero fault codes only glow plugs and SRS or something.

 

[ajlsl600]

Someone, will be along. Frankly never heard of that

 

[limp]

I’ll really appreciate any help.

 

[M80]

If the revs are dropping, but the speed isn't, it must be going up a gear.

The only time I've experience anything like was at 1,800 revs, there would be a surge to 2k revs for a brief moment or 2, then back again.
In my case it would seem the auto box was slipping (bit of a guess, but it wasn't the TC). I sold it. That isn't as you describe though.

 

[limp]

If the revs are dropping, but the speed isn't, it must be going up a gear.

The only time I've experience anything like was at 1,800 revs, there would be a surge to 2k revs for a brief moment or 2, then back again.
In my case it would seem the auto box was slipping (bit of a guess, but it wasn't the TC). I sold it. That isn't as you describe though.

Exactly what it does, the revs drop but the speed is consistent. Oddly enough it doesn’t happen again until I completely come to a halt, like on the traffic lights.

 

[oigle]

Wonder if your TC is locking and unlocking?

 

[limp]

Wonder if your TC is locking and unlocking?

What is the TC? ‍

 

[Blobcat]

What is the TC? ‍

Torque converter

 

[limp]

alright

Torque conv

Torque converter

Alright thanks. I’ll try to change the fluids in the transmission. See how it goes, how many liters does the transmission take?

 

[oigle]

alright

Alright thanks. I’ll try to change the fluids in the transmission. See how it goes, how many liters does the transmission take?

Depends if you just drain the sump or flush the system properly. TC holds quite a bit that doesn't drain automatically. Would suggest a proper flush is much better. Quantity of oil will vary with flushing. Quite a few litres....

 

[limp]

Depends if you just drain the sump or flush the system properly. TC holds quite a bit that doesn't drain automatically. Would suggest a proper flush is much better. Quantity of oil will vary with flushing. Quite a few litres....

Thanks Oigle, I have an idea on how to flush the transmission system but any info on how to it properly would be appreciated. I also what to change the diff oil and transfer box any help on that will be welcome too the truck has around 125***KM on the clock.

 

[oigle]

Can only flush TC with motor running. Need to drain sump and refill with fresh fluid. Then disconnect the return line from the tranny cooler and run engine. Dirty fluid will pump out of return line into a suitable receptacle. Flush 3 or 4 litres through and then refill sump and run more through until fluid runs clear at drain. Then reattach and fill to proper level. That's as good asd you can get. You'll need 10-12 litres fluid.

 

[oigle]

Mods - this query should perhapd be given its own thread so it doesn't go away from the original purpose of such a massive thread.

 

[limp]

Can only flush TC with motor running. Need to drain sump and refill with fresh fluid. Then disconnect the return line from the tranny cooler and run engine. Dirty fluid will pump out of return line into a suitable receptacle. Flush 3 or 4 litres through and then refill sump and run more through until fluid runs clear at drain. Then reattach and fill to proper level. That's as good asd you can get. You'll need 10-12 litres fluid.

Thank you for the info Oigle.

 

[limp]

Mods - this query should perhapd be given its own thread so it doesn't go away from the original purpose of such a massive thread.

Yeah you are right.

 

[Blobcat]

Mods - this query should perhapd be given its own thread so it doesn't go away from the original purpose of such a massive thread.

Moved into new thread

 

[Botus]

TC lock up failing on a Merc is normal

the idea is 97% to 98% slip through a torque converter is the most efficient they can achieve with the oil sloshing about - circa late 1980's they added a bit to mechanically lock them together under light load to get 100% drive - it wear out and costs lot to fix

just read there is a procedure to try and re-calibrate - but I expect its toast

 

[oigle]

TC lock up failing on a Merc is normal

the idea is 97% to 98% slip through a torque converter is the most efficient they can achieve with the oil sloshing about - circa late 1980's they added a bit to mechanically lock them together under light load to get 100% drive - it wear out and costs lot to fix

just read there is a procedure to try and re-calibrate - but I expect its toast

Think you are being very pessimistic there. I would do flush etc first before believeing it was knackered. Perhaps the issue is not too much of a problem anyway requiring major expenditure.