! HELP ! loss of power in reverse

[falcons]

ok so for the last week my p6b 3.5 with a bw35 has had this problem i have tried replacing the fluid per Harveys post but still am experiencing the problem i have tried tightening the linkage that hasn't solved it i have noticed that when the gearbox is cold i dont have a problem in reverse but as soon as it warms up (gets worse the hotter it gets) i loose all power in reverse, any help on diagnosing this would be a great help.

falcon

 

[falcons]

well looks like one? of the clutches has quit on it slips at all gears at high revs very noticeable after kick down, so next question, i have a m8 with a bw 65 lying around are they just a straight swap or am i going to have to shorten the prop and a host of other things that id rather not do.

ps do u have to do any modifications to fit a lt77 (?sd1?) box in its place.

 

[harveyp6]

i have a m8 with a bw 65 lying around are they just a straight swap or am i going to have to shorten the prop and a host of other things that id rather not do.

It depends on the origin of the BW65. The only one that almost goes straight in is the one from the P6B, and even that will need mods to fit the selector cable and a few other minor mods. SD1 boxes are close but need modification, one from anything else is a non-starter really.

ps do u have to do any modifications to fit a lt77 (?sd1?) box in its place.

That conversion has been well documented on here, use the "search" function and you should find plenty about it.

Easiest way is to fix your box, but you seem to have discounted that as an option already.

 

[falcons]

Easiest way is to fix your box, but you seem to have discounted that as an option already.

have discounted that as i was quoted over £1500 to fully refurbish it that and as i can grab a bw65 for little over £150 i was hoping for a EASIER option however i noticed that u are somewhere in Essex, and Currently over 35 years worth of fixing 35 boxes assuming this is your trade what would you charge or if it is something that is relatively simple as i have NO clue when it comes to gearboxes could you inform me of the proper procedures to refurbish her. assuming the information i have received is correct from a diagnosis over the phone it could be the torque limiter, if that is the case how would i fix it? any help would be appreciated and i thank you for your speedy repli

falcon

 

[harveyp6]

Slip in all forward gears will be the front clutch, if you have slip in reverse as well that's either the rear band if you've also lost engine braking in "1", or the rear clutch. In most cases you either lose forward or reverse drive not both, but if you have and it does kickdown I'd check the fluid level first to be certain that was correct, if it is, then in the absence of any more detailed information I'd say you're looking at having the box out rather than being able to do anything in-situ, but without the special installers you won't be able to replace the piston seals, which are likely to be the underlying cause of the problems.

£1500 for remove/overhaul/refit is probably a bit dear, but with a few unexpected extras along the way (like snapped exhaust manifold studs as an example) it's easy for the price to creep up.

A "torque limiter" is a new one on me, if you mean the torque converter, I think it's very unlikey that's the problem if it drives as normal, but slips under high load conditions.

Secondhand boxes are a lottery as they don't respond well to long periods of storage, and £150 isn't cheap either.