Engine/Transmission (1994 - 1998) ATF Question

[AlFischer]

Just finished doing a rebuild on son's 96 47RE. Suncoast TC and new Suncoast VB, input shaft and a complete kit. Went quit well for a couple of a amateurs. (the driveway drop without a proper transmission jack was not good) Also replumbed the entire trans cooling system. Threw away Dodges crappy quick disconnect lines (all leaking) and used Aeroquip 322 hose with push on fittings. Also B&M cooler under the bed.



Plan to change the fluid after 1000 miles, check bands, change filter and install the Suncoast Controler. I DON'T want to start a ATF war but need guidance on best fluid to use.



Well, the 'book' says ATF+3 but seems that is becoming unavailable. (found 2 cases after a days search)



The transmission does shift quite hard (the original of course was getting slippy like a Dodge and heating) We had Amsoil ATF in it before the rebuild. I think it is way too hard. Want firm not a sudden jerk.



If we use Amsoil will the shifting be smoother or harder?

Which ATF would smoothest? Am actually considering Tractor Fluid, as I understand it gives good results. Would it be smoother or harder?



The local transmission parts house says the pros put DextronIII in everything. Had cases of it stacked on the floor. Nothing else. He then mumbled something about the 'modifier' but did not elaborate.



So what is the wisdom from you experts? Amsoil? Tractor Fluid? Whale Oil?

 

[AWray]

Al - Does Suncoast provide a warranty with their DIY rebuild kit? If so, use what they recommend. Call them and see why they recommend ATF+3. When I purchased my trans, I asked what fluid they recommended and their response was to use ATF+3 because it is cheaper than ATF+4 and they wanted the fluid changed every 12 months or 15k mi for the warranty. Now that I am past the 3 yr window, I use AMSOIL.

 

[KingS]

amsoil is good other wise atf-3 atf-4 will slip to much for that transmission the firmness of the shift is do to VB if you use fluid to soften the shift all you are doing is slipping the clutch pack and adding to premature were out.

 

[AlFischer]

Suncoast states ATF+3 on the instructions. However, ATF+3 is now an extinct animal. I asked in a email to Suncoast and got no response. No indication from them on changing at any interval, however that is my practice. Probably need to email them again.



I did not say the shift was firm. Firm we want. It is HARD. Son says 'kicks like a mule'. Gave the TV cable some more slack as in their advice when I spoke with their rech "Arnie". Planning to check pressures when I get a pair of gauges. They said pressure would be 'about' 20 lis higher that shop manual specs.



What effect would band asjustment have on shift characteristics? Followed the book for torque and turns to loosen, but not 100% sure of calibration of torque wrench.

 

[wicked6]

Run a blend of Mobil-1 ATF and the ATF +3. I had a transmission years ago that shifted *exactly* the way you describe, (key differences: 100% Type F in a GM transmission) and it cleaned up nicely with a Mobil-1, 5 quart service. . Now, the friction modifiers are WAAAAY different between the Type F and the ATF +3, but the result will be similar. . Shifts still felt very positive, without the gorilla-wielding-a-15-pound-sledge effect. .



If you are an Amsoil man, go that route. . Any synthetic on the market IS compatible with the older ATF +3... . no snake oil there... You shouldn't get penalized for running it, unless Suncoast explicitly states it in the warranty paperwork. .



HTH -



Linc

 

[AlFischer]

I understand that the valve body will have an effect on the shift. I assume that the valve body supplied puts out more pressure than standard. Anyone with a Suncoast VB that has checked actual pressures? There are adjuctments in the shop manual and pressure checks but that is for the stock. All they said is 'about' 20 lbs higher. Have not checked the pressure but next week son is bringing truck down. Trying to get my ducks lined up.



Also, which adjustment would affect the shift firmness?

 

[Cooker]

These trannies do not need ATF +3. Dex will be fine. There are more than a few of us running rebuilt trannies with Dex.