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View Full Version : '86 Prostar transmission help


Tommyp99
02-24-2011, 06:58 PM
I recently bought what was supposed to be a completely rebuilt '86 Prostar. The engine runs great, but I have transmission problems. 1: I can't get the transmission into neutral and the shaft spins on start. I disconnected the cable and it will shift from fwd directly to reverse (did it twice and quit). 2: I have seen it in neutral, but the shaft still spins at about 100 RPM. 3: The fluid level is high, but would being too full cause it not to shift? Please help.

rjracin240
02-24-2011, 11:34 PM
Cannot offer any advice but sure would like to see pictures of your new boat and welcome to the Mastercraft family

JLeuck64
02-24-2011, 11:53 PM
That might not be a problem...
I am thinking you have just a little bit of drag in the clutch packs is all. 100 rpm in neutral is what leads me to believe that.

milehigh970
02-25-2011, 12:04 AM
That might not be a problem...
I am thinking you have just a little bit of drag in the clutch packs is all. 100 rpm in neutral is what leads me to believe that.

i was thinking the same thing... I would get to proper level first.

CantRepeat
02-25-2011, 05:05 AM
If you have rotation with the cable disconnected and someone has just recently rebuilt the transmission then they probably didn't check the clearance on the clutch pack and used the incorrect snap ring. IE the clutch pack is to tight.

Have you ask the PO if and who did the trans work?

dmminfla
02-25-2011, 11:19 AM
The tranny is a Borg Warner Velvet drive. It's most likley that someone ran it low on fluid and warped the forward clutch plates. To fix it you will need to pull it and change the plates and set the propper gap. However if you can live with the forward "Creep" it can still work fine for some time. My 86 Skier (Prostar was not made in 86) had the same problem. Be very carful not to switch to reverse quickley because with the drag on the forward chuch plates could cause the rear plates to snap. It happened to mine.

blakehardesty
02-25-2011, 02:29 PM
Mine spins some too. I would guess way less than 100 rpm (like 20 rpm)

CantRepeat
02-25-2011, 03:16 PM
The tranny is a Borg Warner Velvet drive. It's most likley that someone ran it low on fluid and warped the forward clutch plates. To fix it you will need to pull it and change the plates and set the propper gap. However if you can live with the forward "Creep" it can still work fine for some time. My 86 Skier (Prostar was not made in 86) had the same problem. Be very carful not to switch to reverse quickley because with the drag on the forward chuch plates could cause the rear plates to snap. It happened to mine.


I would assume the friction plates would burn up before the metal plates would warp causing slippage, not drag. Creep is normally a by product of bad clearance or a poorly adjusted cable.

Covi
02-25-2011, 04:57 PM
I recently bought what was supposed to be a completely rebuilt '86 Prostar. It's beautiful and the engine runs great, but I have transmission problems. 1: I can't get the transmission into neutral and the shaft spins on start. I disconnected the cable and it will shift from fwd directly to reverse (did it twice and quit). 2: I have seen it in neutral, but the shaft still spins at about 100 RPM. 3: The fluid level is high, but would being too full cause it not to shift? Please help.

Photos, photos, photos welcome and lets get this thing running proper!

Tommyp99
02-25-2011, 07:12 PM
Thanks for all then info. The transmission is a 10-17-004 and the engine was completely rebuilt. As I look at the transmission rating, it's probably getting too much horsepower (rated at 255 and the seller said engine put about 400).

Covi
02-25-2011, 07:22 PM
ROTF...........Someone had to buy it. Welcome.

Covi
02-25-2011, 07:23 PM
That boat has been all over this forum.

greenexhaust
04-16-2013, 11:16 PM
454 came with 1.5.1 ratio trans the one on there is not recomended maybe this could be some of your problem