A-727 Slapstik, 2-3 slipping when hot

[jforest1]

Alright, guys, there are a lot of factors here so bear with me as this is my first anything to do with transmission.

I'm in D on my 3-speed slapstik A-727.  Engine cold, everything works fine.  After about 30 minutes of driving 60-80 mph, and temperature reading middle of hot and cold, it seems as if i'm between gears/temporarily dropping in neutral between 2-3 shift when applying gas.

That is:
In "D"
Driving at 50mph or so.
Apply gas
Transmission seems to try to shift, but doesn't; instead, my RPMs spike as if I were in neutral applying the gas
Eventually it either shifts to 3 or I get scared and let off the gas and transmission drops it back in 2.

My gut is saying this may have to do with heat issues.  I don't have enough mechanical experience to trust my gut but as it may pertain, here's another possibly related issue:
Had a Vintage Air Gen IV R-134a AC system installed, which put a condensor in front of the radiator (less air flow).  I've got the stock 4-blade fan.  I'm unsure if my thermometer is working correctly as I've never seen it go about halfway between cold and hot, but the engine has been pretty damn hot before.  Again, hot enough to cause overflow hose on radiator to get some use as coolant is boiling over, even when full.  I've got the stock cast iron radiator.

So let's say my thermometer is busted and engine bay is running hotter, would this have any chance of affecting the transmission?  I know transmission coolant lines run through bottom of radiator.  If these lines are hot and fluid expands, how will it affect transmission's operation?  Or is my gut wrong and it's likely something else?

JF

[PlumCraZRT]

You are probably not wrong in being concerned over the operation of your transmission.  You may also be right about the temp guage reading incorrectly.

They say the number one killer of transmissions is excessive heat, so cooling down the transmission should just about always be a priority.  I've read that it's VERY difficult to over-cool them (particularly nowadays since these cars are rarely driven at freezing temperatures).

I would guess that the problem goes beyond the transmission being warm.  I'm not a transmission expert, but I would think that the bands are out of adjustment.  I would get a large transmission cooler and bypass the radiator (and make sure you don't mount the cooler directly to the radiator/condenser.  Then I would take the transmission in and have it looked at.  The techs should be able to check that all the line pressures are good or not.

[tman]

trans is slipping, check fluid level.  Hope Trans guy will see this. 

[tman]

Oh yeah, when checking the fluid, take a sniff.  If it smells burnt, that is not a good sign.

[jforest1]

Tranmission cooler?

https://www.yearone.com/Catalog/Show?bid=24&sid=155&ssid=1407&pgid=0

?

JF

[tactransman]

It sounds like your throttle pressure linkage is not set right, or you are losing your direct (third gear) clutch pack. Yes, check your fluid level (idling in neutral)

[jforest1]

Oh yeah, when checking the fluid, take a sniff.  If it smells burnt, that is not a good sign.

Alright, checked this morning and it smells slightly burnt, but unfortunately didn't have enough time this morning to check fluid level.  Will do so when I get home.

JF

[Super Blue 72]

Terry, would a tranny cooler help this situation or is it just a bandaid if the third gear clutch pack is starting to slip?

Is there an additive that can be added to help or is rebuild the only option? 

Thanks!

[jforest1]

So on the heat issue...what are the different things one can do to cool down the engine area? 

1.  I'll preface it with saying that I'd rather not replace the radiator, on account of it being the original and *seems* to be in good shape.  Now, if that is what is causing the heat issue, then I will and not look back, but I need to understand the implications there.  For example, I'm currently using the "green" coolant that no longer works for aluminum radiators.  So I imagine I'd need to flush the system, and never go back to green.  If so, is there anything I'd need to replace to allow for the new coolant?

2.  electric fans on the radiator.  usually these are front-mounted, correct?  If so, I'm not sure I can do this because the A/C condenser is on the front passenger side of the radiator.  i've seen dual setups...i assume there are single electric fan setups that would go on the driver side of the radiator?

3.  belt fan upgrade to from 4 blade to 6 blade belt fan.  this one seems pricey:
https://www.yearone.com/Catalog/Show?bid=24&sid=125&ssid=530&pgid=7377
this one seems cooler (does more blades = cooler engine?):
https://www.yearone.com/Catalog/Show?bid=24&sid=125&ssid=1474&pgid=7377

4.  fan shroud - i've currently got a shroud that is jimmied onto the radiator.   not sure on the size but i did see a couple of different sizes in the Y1 catalogue.  does size matter here and why?  is it only tied to the fan size or are their other factors?
https://www.yearone.com/Catalog/Show?bid=24&sid=125&ssid=254&pgid=6915

5.  transmission cooler system:
https://www.yearone.com/Catalog/Show?bid=24&sid=155&ssid=1407&pgid=0
That looks like an engine oil cooler system, rather than transmission cooler system.  Or are they one and the same?  If I'm not mounting this against the radiator, where do I mount it?

6.  any other things I can do?  bag of ready ice on the engine every day? 

JF

[jforest1]

And maybe I'm just looking for an excuse but Y1 has a father's day sale right now so if there's anything I can go ahead and grab that will be good for the car's run temperature anyway...please make some recommendations for this newbie.

JF

[72cudamaan]

1: Green antifreeze works just fine . The newer stuff is for people that don't/won't change there antifreeze
on a 2-3 year cycle.
2:Yes, a proper fitting fan shroud is a must. And you probably should have upgraded to a 6 or 7 blade
fan when you did the a/c upgrade.
3: Electric fans are usually NOT  necessary. They may help but a rigid fan blade usually cools better than an electric.
4: You need to address all transmission issues now, before you do major damage. Don't drive it until you
get it looked at or repaired. Adjustments to the bands and throttle pressure (along with a flush) might
be all you need if more damage isn't done.

[tactransman]

Your engine temp problem is not causing your trans problem. It sounds like you have a direct clutch problem and when the trans gets up to normal operating temp it is slipping worse from a pressure loss probably ( bad drum lip seals or worn sealing rings or both). Does this thing delay in reverse engagement when warmed up?

[jforest1]

Okay, got some time to gather a few more symptoms.  Got a power steering fluid leak, needed coolant, and when I let it warm up so the engine would cycle the coolant, went from green to yellow.  While it was warm I checked the transmission fluid levels in neutral and all was well.  It didn't have any issues reversing then, but then again I don't have trouble dropping into 3rd gear until I've been driving 60-80 for 20 minutes or so...

JF

p.s.  i have a 6 blade fan.  i could've sworn i had 4 though!  and my memory must be fading because the ac condensor covers the entire radiator. 

[jforest1]

Alright.  After I fix the power steering box leak, to the transmission shop it goes.

JF

[jforest1]

In the shop.  Here are my notes from talking with them on external inspection (they haven't dropped it out of the car):

1.  broken transmission mount, missing bolt on transmission mount (at rest, out of alignment toward driver side by 1.5") -- will fix,
2.  clutch/bushing material in the pan (not a lot) could come from band or clutch -- will investigate,
3.  different valve body as opposed to original (cheetah valve body and deeper pan to accommodate-firmer hit of the clutches) -- not a problem, just a note,
4.  cover bolts are not correct size - will fix

theories for original problem:
(cuda-challenger forum theories):
1. Bands out of adjustment
2. Throttle pressure linkage not set correctly
3. Losing direct (third gear) clutch pack and it's starting to slip at operating temperature due to pressure loss (bad drum lip seals/worn sealing rings/both)
(oakwood transmission in flowery branch theories):
4.  perhaps noted material getting in valve body?
5.  checkball wear allowing fluid to pass through plate in valve body (upper to lower)?


Thoughts/comments?

JF