Factory Five Racing Forum banner
1 - 20 of 21 Posts

·
Junior Charter Member
Joined
·
1,524 Posts
Discussion Starter · #1 ·
Hey Guys, I've had a MK3 sitting unfinished in my garage for more years than I care to admit. It was at the go kart stage when life got in the way of my finishing. I just started working on it again and my first step (after cleaning) was going over all the fluids. I decided to check the transmission first as I've seen some drips that made me suspicious. Well I had a reason to be. I pulled the filler plug first and immediately saw ATF draining from the top plug. After that stopped, I pulled the drain plug and saw a flood of first water and then ATF coming out. Obviously the water has me more than a little concerned so I pulled the shifter off to see what it looked like in there. Below is what I saw.

A few years ago a pipe burst in my garage, it got the cobra wet, I thought it was just some surface water, I didn't imagine it could have gotten into the transmission.

The transmission is a T-5 from an '89 Mustang GT

Here are some questions:
1. With that amount of rust, I assume the transmission is shot, is that correct?
2. If it is shot, should I get it rebuilt or just replace it?
3. If I should replace what do you recommend?
4. Where else should I look for potential water damage?

Thanks for any help


Wood Fixture Automotive tire Gas Font
 

·
Registered
Joined
·
234 Posts
Before any drastic action I would place rags inside the shifter housing and clean the rust with a scotch brite pad to get as much as possible .
Then pour a generous amount of ATF into the housing, and refill the trans. Start her up and shift through the gears with the rear up on jack stands. If it shifts as it should let it run to full temp, then drain and refill the trans. a couple of times. Keep us posted.
 

·
Vegasjack
Joined
·
117 Posts
Just FYI in case you didn't know. You can fill your transmission by pouring ATF into the shifter box you show in the picture. There is a couple holes at the bottom that lead directly into the transmission and in many circumstances a lot easier to do than using the side fill plug. No doubt this is how the water got into the main transmission. If water gets into this shifter box it will immediately drain down into the tranny. If you clean this area, be sure to plug these holes or a lot of junk is likely to flow down into the main transmission area. These holes are there and are normal.
 

·
Registered
Joined
·
1,348 Posts
I'd be worried about rusted out gears lower in the transmission case. the fact that the ATF came out first from the upper fill hole means that the water was down below. there must have been an lot of water from that pipe bursting. I would have thought the entire cockpit of the car would have had standing water in it to get enough water to seep past the lid on the shifter box to cause this. on my T5, the top of the shifter box comes around the edges of the box too, so not sure how the water found it's way in.
 
  • Like
Reactions: toddr

·
Registered
Joined
·
234 Posts
Vegas and Chewy: All good points, but what does he have to lose after a clean up and a couple of flushes? Worth a try.
 

·
Junior Charter Member
Joined
·
1,524 Posts
Discussion Starter · #6 ·
Thank you for the replies. My fear, is what Chewy brought up. I agree that the the transmission might work after flushing the fluid, but if the gears are rusted and weakened what are the chances of a future catastrophic failure?
 

·
Registered
Joined
·
85 Posts
I can’t imagine that much water go in there without the trans having been submerged. Perhaps it looked like a lot of water but was in fact a few ounces? If you took a clean new trans and added half water/half trans fluid, I could see the bottom components being totally rusted. In your scenario I’m inclined to say it’s probably not that bad. Having said that, if you do decide to change it, I’d replace it not rebuild it. T5’s are still fairly easy to come by
 

·
Registered
Joined
·
234 Posts
Any rust on the gears I suspect would be superficial...and therefore of no consequence...we're talking fresh water, not sea water...don't stress it...flush it and move on...In a previous life as a shop owner/tech I've come across many flooded cars...rear axles and transmissions water logged...4x4 submerged in rivers...all ingested water...a drain and a couple of flushes later all was fine....
 

·
Registered
Joined
·
7,808 Posts
Any rust on the gears I suspect would be superficial...and therefore of no consequence...we're talking fresh water, not sea water...don't stress it...flush it and move on...In a previous life as a shop owner/tech I've come across many flooded cars...rear axles and transmissions water logged...4x4 submerged in rivers...all ingested water...a drain and a couple of flushes later all was fine....
I agree, it's worth a try, and there won't be a catastrophic failure. If it fails it'll be slowly and noisy
 

·
Registered
Joined
·
402 Posts
Having been in the marine business I've seen a whole lot of instances where water was in places it shouldn't be. A little rust on the gears doesn't worry me too much. But the bearings are a different story. If they got some rust they will fail in short order. Odds are they did get some rust. You can flush it and run it. Might run ok for years, or not. So can you accept the risk of the trans failing once you've finished the car? If not, I would at lest have someone go thru it now.
 
  • Like
Reactions: toddr

·
Registered
Joined
·
1,348 Posts
Cost me around $400 for a transmission shop to inspect my donor T5. It was fine and no rebuild was done. New one can be had for just over $1000. Food for thought
 

·
Registered
Joined
·
1,348 Posts
Sorry, meant $2k. Fat fingers...

Rich, PayPal me the money and I'll get them shipped out right away! 🤑
 

·
Charter Member
Joined
·
1,097 Posts
I had my T5 looked over by a good local manual tranny shop. It was a little over $200. So, I'd call around, it might be worth the effort to take it in. Find a good reputable place. You could reach out to some local racers or engine builders if you know any.
 

·
Junior Charter Member
Joined
·
1,524 Posts
Discussion Starter · #17 ·
Thank you for the many helpful replies. I think my plan is to continue to sort through the mechanicals and once I have the car running I can run through the gears and see how it sounds/feels. I will likely then pull the transmission and get it looked at.
 

·
FFCobra Fanatic
Joined
·
2,595 Posts
Thank you for the many helpful replies. I think my plan is to continue to sort through the mechanicals and once I have the car running I can run through the gears and see how it sounds/feels. I will likely then pull the transmission and get it looked at.
Sounds like you enjoy doing things twice. It's out right now, take it apart and be sure, then no worries. jmo
 
1 - 20 of 21 Posts
Top