Community Forums

iamdogstar · 02-25-2021, 03:14 AM

Hi there

Some of you may remember me from earlier this year asking about Transmission for my Winnebago Brave Chevrolet

I managed to complete the project of changing the Transmission Filter and Oil - it all went to plan and i was so hopeful it would resolve the gear changing problem but unfortunately it didn't

My old girl (registered in 1993) is Automatic Transmission and changes from 1st to 2nd no problem ... but then at about 30mph starts losing power and struggles to change into 3rd and 4th gear ... if i put the accelerator down she then chucks out some smoke

I've been told i could possibly need a new gearbox but it seems here in the UK i'm struggling to source one

I've contacted a couple of places in USA but they don't ship to UK

Any of you RV'ers out there able to point me in the direction of possible help with this

Thanks in advance

jimjenturner · 02-25-2021, 06:29 AM

I'm not sure its a transmission problem. When you say it puffs smoke when trying to shift what color is the smoke if its blackish my guess is the engine is running rich on gas for some reason creating a power loss. Now if its blueish it could be valve stem seals or rings keeping the engine from making enough power to make transmission shift correctly. Just a guess.....

twinboat · 02-25-2021, 06:33 AM

What you discribe is an engine problem.

Start with replacing the fuel filter.

US1 · 02-25-2021, 07:46 AM

You would be wiser to take the RV to a qualified mechanic to have it professionally diagnosed. You may be replacing parts that are good. That can get very expensive, given now you are considering a transmission (gearbox)
If I recall, it was determined you actually have a diesel?

VanDiemen23 · 02-25-2021, 09:07 AM

do you know what transmission you have? GM had a fairly problematic transmission at the time - the 700R4. 2nd and 4th used the same drum so it got twice as much wear as the other ones. I had a 3/4 ton truck that went over 150,000 miles just fine - until I started towing, and then the original transmission disintegrated, followed by three re-builds suffering the same fate.

If you are lucky you got a 4L60E or 4L80E where the 700's problems largely got solved.

I could see the transmission having difficulty getting into gear, bogging the engine, and if it's a diesel, making a bunch of power to compensate and thus the black smoke.

When you changed the filter, did you see a lot of glittery particles or did it look clogged? Was the fluid dark with a bad smell?

iamdogstar · 02-25-2021, 11:43 AM

yes it's a diesel

i just can't get any decent mechanic to sort it here in Liverpool ... had a guy doing it for the last couple of years but since sorting it to get through it's MOT last september (which it did get through) ... it's never been right since ...

a commercial motor company are willing to look at it but want to charge £80 +VAT per hour and I can't help but feel they might overcharge or do things that aren't necessary too

i'm stuck between a rock and a hard place now

Quote:

Originally Posted by US1

You would be wiser to take the RV to a qualified mechanic to have it professionally diagnosed. You may be replacing parts that are good. That can get very expensive, given now you are considering a transmission (gearbox)
If I recall, it was determined you actually have a diesel?

iamdogstar · 02-25-2021, 11:45 AM

I believe i have a 4L80E
the oil was pretty dark when i changed it in the transmission pan and there were a few gritty bits but nothing too sinister in there, no bad smell or glittery bits ... changed the filter in the pan too, no problem ...

it's not black smoke coming out ... mostly white

Quote:

Originally Posted by VanDiemen23

do you know what transmission you have? GM had a fairly problematic transmission at the time - the 700R4. 2nd and 4th used the same drum so it got twice as much wear as the other ones. I had a 3/4 ton truck that went over 150,000 miles just fine - until I started towing, and then the original transmission disintegrated, followed by three re-builds suffering the same fate.

If you are lucky you got a 4L60E or 4L80E where the 700's problems largely got solved.

I could see the transmission having difficulty getting into gear, bogging the engine, and if it's a diesel, making a bunch of power to compensate and thus the black smoke.

When you changed the filter, did you see a lot of glittery particles or did it look clogged? Was the fluid dark with a bad smell?

JohnBoyToo · 02-25-2021, 11:47 AM

Have you tried changing all filters to make sure you aren't starving it for fuel or air ?

If not an engine problem, have you tried manually shifting the gears to see if a little longer or shorter in the lower gear would be a temporary stopgap ? good luck

iamdogstar · 02-25-2021, 11:47 AM

when i start her up and she's stationary the engine sounds just fine, nothing untoward

it's white(ish) smoke coming out - no black
and it's not constant, it just puffs out when trying to change up a gear (automatic transmission) .... going through 1st and 2nd seems fine enough ... and reverse is no problem either

Quote:

Originally Posted by twinboat

What you discribe is an engine problem.

Start with replacing the fuel filter.

iamdogstar · 02-25-2021, 11:50 AM

it's not black(ish) smoke
looks more white to me
the engine seems to be running fine - sounds fine and when stationary wouldn't think there's a problem at all ....
reverse, first and second are all good
it just gets into difficulty after about 30 mph and trying to shift up

i'm such a novice with all this, but no decent mechanic available to help me, not for my want of trying but it's just thin on the ground here for mechanics that want to take on a Winnebago (especially those who are not going to charge a very high hourly rate) ..

Quote:

Originally Posted by jimjenturner

I'm not sure its a transmission problem. When you say it puffs smoke when trying to shift what color is the smoke if its blackish my guess is the engine is running rich on gas for some reason creating a power loss. Now if its blueish it could be valve stem seals or rings keeping the engine from making enough power to make transmission shift correctly. Just a guess.....

77Travco · 02-25-2021, 11:58 AM

Quote:

Originally Posted by iamdogstar

it's not black(ish) smoke
looks more white to me
the engine seems to be running fine - sounds fine and when stationary wouldn't think there's a problem at all ....
reverse, first and second are all good
it just gets into difficulty after about 30 mph and trying to shift up

i'm such a novice with all this, but no decent mechanic available to help me, not for my want of trying but it's just thin on the ground here for mechanics that want to take on a Winnebago (especially those who are not going to charge a very high hourly rate) ..

1) When posting about this vehicle in the future, be sure to mention that it's a diesel as that is not common.

2) You are describing an engine problem. Possibly a fuel delivery issue. You need someone that knows what they are looking for to actually drive it down the road and diagnose it. They will probably want you to leave it with them so they can work the problem.

3) Try manually shifting it. When you get fast enough, at a higher RPM and shift to 3rd, does it fall on it's face? I'm betting that it falls on it's face in any gear at a higher RPM.

F4Gary · 02-25-2021, 01:11 PM

Hmm. White smoke usually is a blown head gasket and coolant is leaking into the combustion chamber.
If it is the tranny and it just stays in 2nd gear, then the engine will just be at a higher RPM.

I'm not really familiar with what a diesel does when you floor it in 2nd gear and it doesn't up shift. Sounds like you are over revving it.

iamdogstar · 02-25-2021, 01:42 PM

hey Travco, thanks for taking the time to respond...

yes, i've posted a few times that this is a Diesel ...

i'm trying to find someone who knows what they're doing but is proving so difficult here in Liverpool, there is just no-one responding or willing to help me out ... i'll keep trying

thanks again for your time

Quote:

Originally Posted by 77Travco

1) When posting about this vehicle in the future, be sure to mention that it's a diesel as that is not common.

2) You are describing an engine problem. Possibly a fuel delivery issue. You need someone that knows what they are looking for to actually drive it down the road and diagnose it. They will probably want you to leave it with them so they can work the problem.

3) Try manually shifting it. When you get fast enough, at a higher RPM and shift to 3rd, does it fall on it's face? I'm betting that it falls on it's face in any gear at a higher RPM.

iamdogstar · 02-25-2021, 01:44 PM

cheers Gary, will take your insights on board and maybe i'll go try drive it again without revving too much

Quote:

Originally Posted by F4Gary

Hmm. White smoke usually is a blown head gasket and coolant is leaking into the combustion chamber.
If it is the tranny and it just stays in 2nd gear, then the engine will just be at a higher RPM.

I'm not really familiar with what a diesel does when you floor it in 2nd gear and it doesn't up shift. Sounds like you are over revving it.