symptom help request

[oregondave]

Hey all,

So I had a low mileage used tranny installed about two months ago when the original died. It's been driving and shifting fine until recently, when i've noticed on three different occasions, about a week apart, that it slipped shifting from 2nd to 3rd (revs briefly before shifting)(while in 3). I drive in 3 when the posted speed limit is below 40. Again, it doesn't happen regularly, just once, and on 3 separate occasions.

I've got a 6 month warranty on the tranny and I need to know if I should go back and get my money back. Four months to go!

Thanks!

[1986nate]

Sounds like the brake band is starting to wear and needs to be adjusted asap to prevent it from getting worse and wearing out the high gear clutch.

Slight chance that it could be the tps but I would bet on the brake band.

[oregondave]

Originally Posted by 1986nate

Sounds like the brake band is starting to wear and needs to be adjusted asap to prevent it from getting worse and wearing out the high gear clutch.

Slight chance that it could be the tps but I would bet on the brake band.

Thanks Nate! There is a good transmission shop here so i'll see if they can do it.

[oregondave]

Originally Posted by 1986nate

Sounds like the brake band is starting to wear and needs to be adjusted asap to prevent it from getting worse and wearing out the high gear clutch.

Slight chance that it could be the tps but I would bet on the brake band.

how difficult is it to access in order to adjust? just curious I spoke with the shop and he said he needed to take a look to see how easy it was.

also, should i avoid driving in 3 until it gets adjusted? Going to get it done tomorrow but just curious - is the brake band what provides engine braking?

[oab_au]

Originally Posted by oregondave

how difficult is it to access in order to adjust? just curious I spoke with the shop and he said he needed to take a look to see how easy it was.

also, should i avoid driving in 3 until it gets adjusted? Going to get it done tomorrow but just curious - is the brake band what provides engine braking?

No Dave the over run clutch does that. Third gear will be fine, you can keep driving in third. You just need to do the brake band adjustment, to stop the flaring from second and third.

Harvey.

[oregondave]

Originally Posted by oab_au

No Dave the over run clutch does that. Third gear will be fine, you can keep driving in third. You just need to do the brake band adjustment, to stop the flaring from second and third.

Harvey.

That's right. I forgot. Thanks Harvey!

Out of curiousity - what exactly does the brake band do?

I have to say i'm amazed with the incredible technical knowledge you guys have. This site is a godsend.

[oab_au]

Originally Posted by oregondave

That's right. I forgot. Thanks Harvey!

Out of curiousity - what exactly does the brake band do?

I have to say i'm amazed with the incredible technical knowledge you guys have. This site is a godsend.

When it is in first gear, the forward clutch is on so the epicycle gear-set is giving the lowest reduction. For second the brake band comes on to hold the front Sun gear stationary so that the epicycle gears have to walk around the sun gear. This reduces the reduction to give second gear ratio.

For third gear the band is released, and the high clutch is applied at the same time. If the band is loose, it releases before the high clutch has come on, so the box goes back to first, till the high clutch clamps up.

Nothing is slipping when this happens, it is just a matter of timing, but it can start the band slipping when in 4th gear that will burn it out. That's why it is important to do the adjustment early.

Harvey.