4+3 Maintenance Question
Thread Starter
Intermediate
Joined: Jan 2021
Posts: 39
Likes: 3
From: Georgia
4+3 Maintenance Question
Was going to service the OD unit on my 4+3 transmission for the 1st time and do a radiator flush on my 1988 vett (28,000 miles) The transmission and OD work fine but I have a couple of questions and hope someone can point me in the right direction .
1) On the OD pan when reinstalling I have read to just use the gasket that came with the kit and have read to just use the RTV sealer and install the pan when the sealer is still wet. Which way is the correct way.
2) Should I clean the control valve and sensor as part of the service.
3) Should I use Dexron II or III fluid.
4) Should I do the radiator flush before the trans service or after the trans fluid.
Thank you for any guidance or help you can give me.
1) On the OD pan when reinstalling I have read to just use the gasket that came with the kit and have read to just use the RTV sealer and install the pan when the sealer is still wet. Which way is the correct way.
2) Should I clean the control valve and sensor as part of the service.
3) Should I use Dexron II or III fluid.
4) Should I do the radiator flush before the trans service or after the trans fluid.
Thank you for any guidance or help you can give me.
Oil Producer
Joined: Apr 2014
Posts: 9,387
Likes: 2,749
1) On the OD pan when reinstalling I have read to just use the gasket that came with the kit and have read to just use the RTV sealer and install the pan when the sealer is still wet. Which way is the correct way.
- in this case with the 4+3 pan, is one of the few circumstances id use “the right stuff”. only because the pans are typically very mishapen. yours may be original. if yes, personally id use hylomar with a gasket, applied properly. hylomar has a spexific application technique.
2) Should I clean the control valve and sensor as part of the service.
- this is something i would do, yes. Ive seen more and more cases on this forum where it just needs to be cleaned and then function is restored. so its likely building up gunk.
3) Should I use Dexron II or III fluid.
- i used dex 3, non-synthetic.
4) Should I do the radiator flush before the trans service or after the trans fluid.
- if you are flushing the cooler lines from the 4+3, u can turn your pressure down on the air, and blow it out. this will mean u may have to top up the fluid a second time after you fill.
pics!!! post pics! i personally am a huge 4+3 fan. i tracked mine and it was awesome.
- in this case with the 4+3 pan, is one of the few circumstances id use “the right stuff”. only because the pans are typically very mishapen. yours may be original. if yes, personally id use hylomar with a gasket, applied properly. hylomar has a spexific application technique.
2) Should I clean the control valve and sensor as part of the service.
- this is something i would do, yes. Ive seen more and more cases on this forum where it just needs to be cleaned and then function is restored. so its likely building up gunk.
3) Should I use Dexron II or III fluid.
- i used dex 3, non-synthetic.
4) Should I do the radiator flush before the trans service or after the trans fluid.
- if you are flushing the cooler lines from the 4+3, u can turn your pressure down on the air, and blow it out. this will mean u may have to top up the fluid a second time after you fill.
pics!!! post pics! i personally am a huge 4+3 fan. i tracked mine and it was awesome.
Melting Slicks
Joined: Jan 2014
Posts: 2,193
Likes: 381
From: Lunenburg MA
I use RTV and Mobil1 universal ATF. It's been done a few times over several years without issue. I would personally leave the sensor and valve alone if it's working properly. The radiator flush won't matter to the trans. I also run a 160F thermostat with a modified fan setup which helps the OD run cooler as well.
