4 speeds and colder temperatures.

[Cornpatch MO]

I have been having problems with the syncro's not working right with a fully warmed up trany.. Rips gears a little when shifting fast. Today the air temps are kinda cool (50-55 degree) Soon as the engine was up to 190 degree ( trany cold) I speed shifted and no rip on the gears - synchros worked fine. I expect the 80-90 gear oil was possibly thicker?
Why would that make a difference , and is there anything I can do to make it shift good when hot? ......................................MO

 

[kiwigtx]

Thicker oil is for warmer climates, while thinner oil is for the cooler climates. Some people actually run transmission fluid believe it or not.
Personally I think 80-90 weight is too much anywhere it sticks like brown stuff to a blanket....so it can't be good for fast shifting.

 

[BeeKool]

I have been having problems with the syncro's not working right with a fully warmed up trany.. Rips gears a little when shifting fast. Today the air temps are kinda cool (50-55 degree) Soon as the engine was up to 190 degree ( trany cold) I speed shifted and no rip on the gears - synchros worked fine. I expect the 80-90 gear oil was possibly thicker?
Why would that make a difference , and is there anything I can do to make it shift good when hot? ......................................MO

I run Hydraulic oil in the gearboxes of my old tractors. Works fine, no grinding

 

[mmissile]

All my 833's had ATF in them.

 

[lewtot184]

i'd look at clutch adjustment.

 

[Ranger16]

Mine has a little gear clash when shifting from 1-2 when cold. I decided to change the trans fluid to what is called for in the FSM (SAE 140). Got gear clash in all gears until up to operating temperature. Drained it and went to Sta-lube 85W90 from Napa (the only GL4 I could find). Now I am back to a little gear clash when cold (1-2). Shifts fine when warmed up. I suspect the synchro is a bit worn. Considering the factory fill was 140, I'm leery to go any lighter

 

[Cranky]

My 74 D100 came with ATF from the factory but I went to 80-90 when I messed up a rear bearing pulling something that was pretty heavy. I'm in SE Texas and even with the mild winters we have, it was much harder to shift with the 80-90 in it but it didn't have any gear clash.

 

[Cornpatch MO]

Thicker oil is for warmer climates, while thinner oil is for the cooler climates. Some people actually run transmission fluid believe it or not.
Personally I think 80-90 weight is too much anywhere it sticks like brown stuff to a blanket....so it can't be good for fast shifting.

I know , I think Ma Mopar recommends motor oil? Brewers Performance recommended the 80-90 gear oil with a certain rating.
So why did mine shift better when the oil was cold ( thicker) ? ...............................MO

 

[Cornpatch MO]

I run Hydraulic oil in the gearboxes of my old tractors. Works fine, no grinding

Interesting, I wonder the theory on that?.......................MO

 

[Cornpatch MO]

i'd look at clutch adjustment.

That has been checked and is a new Centerforce dual friction with enough miles to be broken in.............................MO

 

[Cornpatch MO]

Mine has a little gear clash when shifting from 1-2 when cold. I decided to change the trans fluid to what is called for in the FSM (SAE 140). Got gear clash in all gears until up to operating temperature. Drained it and went to Sta-lube 85W90 from Napa (the only GL4 I could find). Now I am back to a little gear clash when cold (1-2). Shifts fine when warmed up. I suspect the synchro is a bit worn. Considering the factory fill was 140, I'm leery to go any lighter

SAE 140? Do you know what year that was recommended for? I know the early 833 was supposed to be like ATF. Brewers recommend the 85W 90 GL4. that is what I have now. Our symptoms are different and I expect it is because of synchros. .................................MO

 

[Cornpatch MO]

My 74 D100 came with ATF from the factory but I went to 80-90 when I messed up a rear bearing pulling something that was pretty heavy. I'm in SE Texas and even with the mild winters we have, it was much harder to shift with the 80-90 in it but it didn't have any gear clash.

Hmmm, maybe I should do a little experimentation with oil weights before I tear down the tranny. When we inspected it, everything looked fine , but I hear that the "dogs" and synchros can be just slightly worn and still cause probelms..................................MO

 

[Cranky]

Hmmm, maybe I should do a little experimentation with oil weights before I tear down the tranny. When we inspected it, everything looked fine , but I hear that the "dogs" and synchros can be just slightly worn and still cause probelms..................................MO

I'd sure give it a try. Mine (light duty 3 speed) surprised me how hard it was to shift during the cold days (below 40) and it wasn't even going to think about shifting quickly from dead cold. It took a bit of driving before it got easier. IIRC, it had around 60k miles on it when I drained the ATF and dropped in the heavier oil and again, iirc, the manual said it could use the heavier oil for heavy duty work. The bearing got messed up when I pulled one of those 1 yard concrete trailers and then backed it off the end of the driveway and tried to pull it back up before dumping any of the concrete. Had to give it some rpm and slip the clutch a little to make it do it and on the drive back to the rental place to return the empty trailer, the trans was noisy in all the gears except for high gear. That was my first and last light duty truck for pulling stuff. I think even my yard cart 95 Dakota has more guts than that old D100 and only my 79 D300 probably is a close match to my present 2500 diesel.

 

[Cornpatch MO]

I just talked to Brewers Performance and they told me why they recommend the 80W90 GL4.. It has mostly to do with how the syncros work. The inside surface of them has a fine thread-like appearance. they are designed to grip onto the smooth surface that they slide on to. Since an internal view is not possible with a tranny that is still together, those fine grooves can become worn and flattened, therefore not gripping as they should. . They are not supposed to be "slick" and that is why GL5 is not recommended, as it has friction modifiers in it similar to what limited slip differentials use. The GL4 does not have those additives.
My assumption is that synthetic and other "super slick" oils should not be used for that reason.
Dan mentioned other problems that could cause my gear ripping including the possibility of a pilot bearing not being drilled correctly ...clearance problems. Also he suggested to decrease the clutch free play as long as the throw out bearing has clearance from the clutch fork. = a little more pressure plate to clutch plate clearance . That will be the first thing I will try. ..................................MO

 

[Cranky]

Do you have more than an 1" of free pedal play? Usually less isn't a good idea but more isn't recommended either.....

 

[BeeKool]

Interesting, I wonder the theory on that?.......................MO

The rear ends end up with water in them do to condensation. Water freezes in winter rendering them immobile unless you thaw them with a Knipco.
I happened to be changing the hydraulic filter on a larger powershift tractor. Had both the 400 Farmall and 7020 A/C in shop. Both rearends drained. My mechanic stopped by for a drink and told me to reuse the Hydraulic oil from the 7020 in the 400. Said that's what he does and it would actually work better.
That was 7 or 8 years ago. The rear-end in the 400 seems to collect less condensation.
Don't know how or if thus helps you, but interesting none the less.

I've also heard of old timers doing this for their old trucks, just be sure it's HyTran or quality Hydraulic oil meant for transmissions.

 

[Cornpatch MO]

Do you have more than an 1" of free pedal play? Usually less isn't a good idea but more isn't recommended either..

I need to check again. Probably more, as it is a Centerforce, and I understand they do have more free play than a 3 finger. I have a light spring on my linkage to bring the pedal all the way up to the up-stop. ................................MO

My answer to Cranky is in his quote??????...........MO

 

[Ranger16]

I know , I think Ma Mopar recommends motor oil? Brewers Performance recommended the 80-90 gear oil with a certain rating.
So why did mine shift better when the oil was cold ( thicker) ? ...............................MO

That is a $64,000 question. Completely opposite of what one would expect.

 

[Ranger16]

SAE 140? Do you know what year that was recommended for? I know the early 833 was supposed to be like ATF. Brewers recommend the 85W 90 GL4. that is what I have now. Our symptoms are different and I expect it is because of synchros. .................................MO

It is in the 1969 service manual, PG 21-29.

"Fill transmission with Multi-Purpose Gear Oil SAE 140.
If shift effort becomes extremely high during cold weather, Multi-Purpose Gear Oil SAE 80 or 90 should be used.
Automatic Transmission Fluid AQ-ATF Suffix “A” (Dexron) may also be used in extremely cold climates."

 

[5.7 hemi]

How many people actually drive their 4 speed cars in the winter? To me the point is mute.