sb66

hey everyone

I am getting everything together for the trans and gear fluid change. I have read to use non synthetic.

Are there ant additives that I need to add to the atf or any additional ingredients besides dexron 3? anti slip?

thanks

Sean

c4cruiser

Just use a good quality Dex3 ATF. No other additives are used.

The lines leading to the radiator should also be cleared out. Disconnect both lines at the OD unit and use some low pressure air to blow out the old fluid. Then re-connect the lines.

Once you have refilled the OD unit, manually rotate a rear wheel for a minute or so. The trans should be in neutral with the engine off. Add more ATF until fluid runs out the filler hole.

jv9999

Does anyone know where this non-synthetic thing came from? I use Mobil 1 in mine. It works fine and runs cooler (infrared temp gauge).

sb66

thanks - I was going to ask about the priming I read about

sb66

I went to summit racing today and spoke with someone who knows big daddy Garlits' transmission guy - when I asked him he laughed and said he had gotten yelled at about it and said non-synthetic only - the guy at summit had been through a few transmissions before talking to Garlits' mechanic - so he understood why I was asking - he said it had to do with metal to metal parts?
I was not sure I understood because so many recommend synthetic - he had followed the same advice until the failed transmissions

C4+3=/=C7

IIRC Redline makes a good Dexron II and Dexron II replacement called D4. I used some Wolf's Head DX-III that was lying around. First go I used M1 ATF, but my research afterwards led to switching from that. A Powerglide design predates synthetic ATF and it's more suited to conventional lubrication.

sb66

this may seem stupid - but since I have never done this before - does it matter which wheel - or both
just want to make sure

thanks
Sean

FOURSPEEDVETTE

Just one needs to be turned.

c4cruiser

Back sometime around 2000-2001, there were a number of threads that discussed why synthetic ATF was not good for the OD unit. One of the members at that time, (Scorp508) had been sort of the leader of the discussion regarding what fluid to use. IIRC he had an '86 with the 4+3 and I think that he had some problems using the synthetic ATF in the OD unit on his car. I don't know if the Corvette Forum has archived those threads, but they may still be available.

Anyway, the overall consensus at that time was that a synthetic ATF was not a good choice for the OD unit as that fluid available at that time did cause problems. But back then, it was still very easy to find the regular DexII/III ATF. Back in the mid-80's when the Doug Nash OD unit was originally built for the early C4's, there probably wasn't a lot of synthetic ATF available. DexII/III was the fluid used in all GM automatic trans and the OD unit could be easily serviced by any Chevy dealer.

Phatphil

Sean...after you have changed your fluids could you please report back with what you used and amounts used, also what else is needed to make this all come together so I can preplan my tranny and OD fluid change? I have been thinking about doing this on my '88 4+3 and with this added info and my FSM, I will attack the change. After you make the change go ahead and drive it before reply and let me know of any seat of the pants feel/change in driving conditions. I am not having any problems as of now just some PM. Thanks for any tips and hints you may feel free to include and pass on.
Phatphil

sb66

yes - I just changed the filter - I will have pictures comparing the filters and the corvette central package as well. I used the right stuff sealant - I will double check the brand - I think it was pennzoil non synthetic atf fluid and lucas gear oil non synthetic - I bought 3 quarts of each to be safe and a fluid pump from Harbor freight $7 and it seemed to work well for both. I just took it around the block earlier to get everything settled and check for leaks. I hope to get it back up on the jacks tomorrow or friday? I should have a more exact number then. after that I will take it out for a longer drive.

Sean

Phatphil

Sean...thx for the reply, hope all goes well with the fluid/filter change and subsequent drive.

sb66

ok so I topped everything off today - I did not remove the cooler lines and blow them out this time - I will most likely try that next time as it was recommended (I was not feeling luck enough to unhook too much at the moment) - The gear fluid took almost a full 2 qts and the atf a full 2 qts. I filled these up to the point of flowing out of the fill opening and waited for them to stop dripping. I wiped everything down stuck my finger in to check the level at the opening of the filler hole. tightened everything up I think 30 ft/lbs and then a smidge more. the fluids I used were pennzoil mineral atf dex/merc (dexron lll) and lucas sae 80w90 gear oil I used right stuff gasket seal (very sticky)

removing the pan go slow and work your way around I used a putty knife after loosening all of the bolts most of the way out. I also used a small paint brush and some lacquer thinner to soften the gasket remains and scraped it off

be patient that part was not difficult but had some hard to reach places I let it dry for quite a while before putting it back together.
tighten the pan bolts lightly and work your way around like wheel studs to 6-8ft/lbs

I cleaned a few things up before re-filling using a harbor freight fluid pump

hopefully this helps (and hopefully I did it right)

Sean

sb66

old next to new




corvette central package




new and clean

c4cruiser

For future reference, the OD unit uses the same filter that was used in Ford FMX automatic transmissions that was installed in early 70's Cougars, some Torinos and Mustangs and a few F-150 pickups.

You can get the OD filter by using these part numbers:
CarQuest (now Advance Auto Parts) 85926
AC Delco TF184
Fram FT1024
NAPA ATP14717
Ford D0AZ-7A098-A

Figure on a price of $7 to $10 except for the Ford filter.

None of these filters come with the rubber grommet, but as long as it's in good shape, you can transfer it from an old filter to the new one.

sb66

thanks - yeas I had ordered the corvette central before I found the reference for those - the bottom image is a wix filter that is a cross reference for those also - but those that you referenced are great - no shipping fee - nothing against corvette central - they had a cheaper mail order package of 18 or 19 - add shipping and you are at $28 - those that you mentioned can be had without that - great reerence

FOURSPEEDVETTE

Did you make sure to add a tube of "GM limited slip differential additive" to the rear differential? Without it, you will soon start noticing a "clicking" noise comiing from the rear end when you go slowly around a corner. This additive is a must!

sb66

I just changed fluid in manual and atf - nothing in the rear end - should that have been changed as well?

FOURSPEEDVETTE

It's a good idea to change that fluid also. Many people never think about changing it. Your car is at least 28 years old now and it may have never been changed.

C4+3=/=C7

Putting in a differential drain plug was very worthwhile for me. I used the kit from Corvette Clinic, but you can also DIY.