Wondering what the odds are that a TH300 that has sat for 5-10 years will self-destruct if put back on the road. My tranny shop thinks I should rebuild it just to be safe. I don't want to spend $650 if I don't need to. Anyone with experiece with automatic transmissions after they have been sitting for years?
i would fill it with fluid and try it out. whats the worst that could happen? worse cae scenario is it needs rebuilt. my 67 special with the ST300 tranny sat for 10 years with most of the fluid leaked out of it. I filled it and started the engine and it has performed perfectly.
Hey GrabSportSedan, Thanks for the encouraging response. My only real concern is that I am working on the car and it would be easy to pull the tranny and have it rebuilt without paying to R&R it. After I finish doing the body work I probably would let the shop do the R&R. But this is a real budget project car that isn't worth much when I finish refurbishing it, so I will probably go with the wait and see plan. (65 Special two door sedan, V6 with a TH300)
What kills the tranny is having no fluid in it! I'd pull the pan and take a look in there- then decide. If no massive amount of muck or corrosion, then you might be just fine. You're gonna have to pull the pan to do a filter change anyway:Brow:
If it worked good before then there should be no reason why it won't still work just fine. As already mentioned, pull the pan and make sure no rust has accumulated from condensation, clean it up , put in fresh fluid and you're good to go. And BTW, if you find a source for those filters, please let us know. I've asked everywhere and have had no luck so far, everyone tells me they have been discontinued for some time now. The gaskets are available but the filters seem to be long gone.
Depends on the environment it was stored in. If any water got into the trans, it might be toast. Rubber parts harden and crack with age. I say if no fluid contamination, re seal it, fill it with fluid and try it.
I often buy used transmissions that sit for, I dont know how long. I check the fluid for color (burnt brown is bad) and smell( I sniff it off the dipstick for a bad burnt smell). If the fluid is good, I feel confident on the swap. Some gaskets may leak a little from sitting, but swell up and seal after warming up and running. So far I am batting 1,000 , with turbo 350 and 400 transmissions. I have a how to rebuild turbo 400 video (vhs, Its not 300 but may help) you can borrow anytime. Also, thanks Kurt for the kind words and starbucks card. Jim
If a trans is stored for a while unsealed or no torque converter, it might not be very good. It can vary from some contamination, to a totally ruined front pump. If the trans was well sealed & oiled, the hard parts should be just fine. However, I have taken apart decades old 400s and found clutch pack piston seals so hard, they broke when bent. If one of these were to fail, you would loose clutch pressure, the power of your engine would burn up the clutch, and your whole trans, torque converter, and trans cooler would be filled with poison. You could avoid this with a soft parts replacement, pretty inexpensive on a TH400. Of course paying someone else for labor raises the cost a lot. good luck, Bruce Roe
Hi Bruce Roe, local shop wants $650 to freshen up the TH300. I have never worked on the internals of an automatic tranny and I assume it is somewhat complicated? Low Buck Jim offered to loan me a tape on rebuilding TH 350 and TH 400 trannies, but I am not certain I want to take on such a project. Seems like lots of small ball and springs that I could misplace or put back in the wrong hole??? Changing rod bearings, timing chains, oil pumps or rebuilding the front end of an A-body does not scare me, it is all those little parts. Special tools needed? What do you think?
Heres a silly piggyback question to this (cause now you guys got me thinkin), what if its a fresh rebuild (never installed/ran) that has sat for 2 or 3 years??
That is a bit much; I've gotten a full overhaul with removal & replacement of a TH350 for less than that. If they aren't buying a new torque converter or any other hard parts, it should be less. If they ARE buying all that, they aren't just doing the soft parts swap I recommend, primarily all seals inside & out. I learned to do 400s by reading the book, one of the simplest 3 speeds to redo. Likely a 300 is simpler yet, but I never did one & don't know what special tools might be useful. A few home made tools can certainly help the job along, I made most of mine. For a soft part redo of a modest mileage trans (but very old), I wouldn't do anything to the valve body, the governor, some other stuff not involved with soft parts. So its a trade off of spending serious time & organization learning a trans, or $650. good luck, Bruce Roe ++++++++++++++++++++++++++++++++++++++
Mine sat for 13 years. Checked the fluids and took it for a drive. There's a gasket leak at the pan but otherwise no issues. I'd just use it.
Hey Bruce, The local shop was doing a complete rebuild, but I am not certain about what they would have replaced. If you go into a shop they always want to do the whole job while they have it apart. I do have an old Ford truck that they just changed the rear seal after it had sat for a few years. Of course the front seal leaks now.... What would I have to disassemble to change just the soft parts? Do you think this is do-able by reading a book? I'm game if I can do it in a day or so. Thanks for the input.
People who are meticulous, patient, and can follow written instructions could do this. My first trans took me a month of very careful work. I put it together 3 times to be sure, then I put it in the car. I'm still slow, more like a day now. The big $ advantage of doing the soft parts is your own labor; not so much saved if someone else is paid to do it. Read the factory service manual and decide. I had a visitor last month and we went through a couple transmissions. One was in beautiful shape, needed conversion to switch pitch. The other had everything wrong, dirt in the pump, piston seals about to come apart. He felt much better about it after the experience & seeing the extremes that are possible. good luck, Bruce Roe
Thanks Bruce, Not sure I have the time to do a one month rebuild, one or two days, yes. I think I will ask the shop instructor at the college where I work if he wants a project for the fall semester. Thanks again,
