Has anyone rebuit a 4+3 OD unit?

[tdr1919]

My OD unit in my 86 is in dire need for a rebuid, I just dont have a grand to drop into it for a professional rebuild (S&K) so I wanted to see if anyone here sucessfully rebuit one and how much did it cost.
Thanks,
Tom

 

[Adams' Apple]

I've built quite a few of them over the years. I'll tell ya...$1000 doesn't seem too high for one, depending on how much damage there is. If the planet set is damaged, that's gonna cost. Then you have the pump assy, and the front retainer(which is usually cracked, or otherwise damaged).
It's usually a $2000+ job at my shop for one of these...and that's just the O/D section. There's rarely a problem with the 4 speed.
S & K is about the only place to get parts, too.
To be honest, until yo know what is wrong with your's it's hard to say how much it will actually cost to repair it.
What exactly seems to be wrong with it?

 

[tdr1919]

Adam,
thanks for the reply, my od operates fine in forward gears, but
after the car/tran heats up I lose power in reverse, and the tranny will pop out of 2nd when you let off the gas. I live on long Island and have visited S&K, Brian showed me a cut-away unit and explained that my problem is due to (I think) the clutches wearing into the casing and this will eventually become a "total systemfailure" actually I think he wanted $1500 & the core, I dont remember, I just dont have any money to lay out and was hoping I could purchase parts a few at a time and then do the job myself, of course, he said there was precision machineing to put his special mod that will prevent this from happening. He did not see my car, I explained the symptoms, He also said with 110k on my car it must have been rebuilt before, because these Nash OD units usually never make 30K!
Tom

 

[Adams' Apple]

Sounds like the front bearing/retainer is worn, which would allow a lot of play in both the O/D unit, and the 4 speed part. Once the retainer wears, it also will allow a lot of free play in the direct clutch-pack, which would explain the slippage in rev.
To be honest, you might be able to rebuild it yourself, but it does take some specialized tools to compress the clutch pack springs. If the spring retainer is not installed perfectly straight, it will almost ALWAYS crack it.
Getting the planetary synchronized is a big pita...even after doing 15-20 of them!:W The planet will come out easy enough, but to re-install the clutches, the planet has to be dis-assembled. The gears on this thing are not like regular gear sets...they must be "timed", or synchronized, in order to get the top of the planet back on, and the nuts tightened.
I'd suggest getting the Factory Service Manual for your car. It has the rebuild procedure in it. If you take a look at it, it will give you an idea of whether or not it is something you can do yourself.

 

[tdf]

Related Question

tdr1919,

Don't mean to hijack your thread. I have at least one of your symptoms as well. I'd like to ask Adams' Apple if poping out of 2nd gear is likely a problem with the 4 speed or the DNE OD? I have been thinking that this issue is with the 4 speed synchronizers. Would be nice to know what is most likely the cause so I know what needs to be looked at.

Thanks in advance for comments

Tom

 

[Old Vette Guy]

tdr1919,

I pulled the overdrive out of my 88 and shipped it to these guys.
www.4speedsbydarrell.com

They did a great job, went through it completely and only charged me 700-800 bucks for the rebuild. They rebuild them for Ecklers and Ecklers will charge you 1400 for a rebuild. Also, anyone on your overdrives, maintain the fluid level. Check at ever oil change. Also in the winter, during storage time, on nice days you will need to drive your Vette and to keep the auto tranny fluid in the 4+3 from getting gummy and jelly.