M35A2 Transmission Fluid Change

[V8srfun]

Damn that sucks... Is that their 50 wt synthetic? Seems strange that the heavier oil would make it shift easier.. either way quite unfortunate.

It shifts with less effort now but fourth will grind really easy if the rpm’s are not just so. I got it from summit it is their transmission specific straight weight. To be honest I think it is synthetic but I don’t remember. I can look at the bottles and find out.

 

[NebraskaFan]

It shifts with less effort now but fourth will grind really easy if the rpm’s are not just so. I got it from summit it is their transmission specific straight weight. To be honest I think it is synthetic but I don’t remember. I can look at the bottles and find out.

I know what you're talking about, it's synthetic. I've looked at it, and have heavily contemplated trying it. It looks like good fluid but for the price I have a hard time commiting to it, for fear that my trans ends up not liking it.

 

[V8srfun]

I know what you're talking about, it's synthetic. I've looked at it, and have heavily contemplated trying it. It looks like good fluid but for the price I have a hard time commiting to it, for fear that my trans ends up not liking it.

That seems to be the thing with these trucks what one likes the other may not. I should have done the more logical approach and started with the cheapest option first but it is to late for that now.

 

[NebraskaFan]

That seems to be the thing with these trucks what one likes the other may not. I should have done the more logical approach and started with the cheapest option first but it is to late for that now.

It really is strange how much they can vary.. I suppose that's part of why these oil threads always blow up haha. I can't blame you for trying the good stuff off that bat, it would be nice to have all the characteristics of the synthetic oil (low pour point is what tempts me).

AFAIK my trans had 80w/90 in it when I bought it, and it always shifted great, no leaks (at least nothing serious), so now I'm kicking myself for trying the 40 wt. Lol so that makes two of us with regrets.

 

[SCSG-G4]

Where is HE?

South west corner of the Tuscon airport (runway is north-south) if you look on Google Earth. I think it's "Teds Trucks" and pictures have been posted of it several times here on the site.

 

[V8srfun]

I just want to be clear my transmission was damaged before I put the new fluid in. I just found it as I was looking in the trans with the top cover off. I believe that the fluid that was in the trans previously (I suspect it was corn head grease) was installed to hide the problem.

 

[NebraskaFan]

I just want to be clear my transmission was damaged before I put the new fluid in. I just found it as I was looking in the trans with the top cover off. I believe that the fluid that was in the trans previously (I suspect it was corn head grease) was installed to hide the problem.

This gives me trust issues.. lol

That is just really sh*** of someone to do.

 

[cattlerepairman]

Olden day horse traders turned car salesmen used to pour sawdust and wood chips into worn transmissions to stop the chatter and make them feel "tight" again. I'd really have trust issues with THAT.

Sent from my SM-G950W using Tapatalk

 

[davidb56]

Olden day horse traders turned car salesmen used to pour sawdust and wood chips into worn transmissions to stop the chatter and make them feel "tight" again. I'd really have trust issues with THAT.

Sent from my SM-G950W using Tapatalk

I 'll post a pic later of second gear and the main shaft that doesn't get enough lubrication. (my theory) The second gear has the modification notches cut into it also, so that didn't help. Im leaning to running a lighter oil since I dont drive on the highway, and the temps around here are mild in the summer and cold in the winter. My truck gets equal time in both seasons.

 

[7bdiver]

Thanks for that chart Frank. Nice to see where sae 40 sits.

I bought 40 wt oil (travellers, from tractor supply) for 76 bucks home. Just put it in tonight. I filled both the t-case and tranny up to the fill plug.

Glad I changed em either way. What came out looked like hersheys syrup. No chunks, and hardly any fines on the magnet. Also, this truck is fairly new to me, but it has been shifting just fine. Best to give fourth an extra second, but that sounds common.

I will take the truck to work and back one day this week. 20 miles one way. I'll let you guys know if any gets puked out and how she likes it.

Outside temp will be 40+/-

Truck is 1985 M35a2

 

[7bdiver]

Thanks for that chart Frank. Nice to see where sae 40 sits.

I bought 40 wt oil (travellers, from tractor supply) for 76 bucks home. Just put it in tonight. I filled both the t-case and tranny up to the fill plug.

Glad I changed em either way. What came out looked like hersheys syrup. No chunks, and hardly any fines on the magnet. Also, this truck is fairly new to me, but it has been shifting just fine. Best to give fourth an extra second, but that sounds common.

I will take the truck to work and back one day this week. 20 miles one way. I'll let you guys know if any gets puked out and how she likes it.

Outside temp will be 40+/-

Truck is 1985 M35a2

Took the truck to work and back, then to the gym and back. All of about 50 miles. I think the shifter movement was a little more crisp, if that makes sense, but had no problems going through the gears at all. Did great. I feel like the sound of the gears was a tiny bit quieter. Its never been more than a slight whir anyway. I didnt get around to shifting the transfer case though.

So yeah, no drips at all, which is what surprised me. Otherwise, nothing incredible, just an oil change. The 40wt looks like its going to be just fine in my truck.

I had no idea what I drained out, but I know whats in it now.

 

[cattlerepairman]

@7bdiver I filled my tranny with 40w to spec, as per TM.
All was fine until I ran it on the highway at speed for two hours. It was puking oil, rust-proofing half of the truck. I did not think tranny fluid; I thought major engine oil leak at first. But engine was dry. Well...dry-ish..you know what I mean.

Clearly spit oil out of the bell housing.

Clutch (brand new) started slipping on the way home. 10 cans of brake cleaner later, that at least seemed resolved.

Pro tip: If you spray brake cleaner into the bell housing from below while laying underneath the truck with the engine running (because you want to hit ALL of the clutch) and are NOT wearing safety glasses, a hat and a raincoat, you did not think ahead.
Anyhoo, the oil level in the tranny seemed to settle where it likes it and has not even dripped since.
These trucks do have personalities.

 

[7bdiver]

@7bdiver I filled my tranny with 40w to spec, as per TM.
All was fine until I ran it on the highway at speed for two hours. It was puking oil, rust-proofing half of the truck. I did not think tranny fluid; I thought major engine oil leak at first. But engine was dry. Well...dry-ish..you know what I mean.

Clearly spit oil out of the bell housing.

Clutch (brand new) started slipping on the way home. 10 cans of brake cleaner later, that at least seemed resolved.

Pro tip: If you spray brake cleaner into the bell housing from below while laying underneath the truck with the engine running (because you want to hit ALL of the clutch) and are NOT wearing safety glasses, a hat and a raincoat, you did not think ahead.
Anyhoo, the oil level in the tranny seemed to settle where it likes it and has not even dripped since.
These trucks do have personalities.

Thanks for the fair warning. I do a 60 mile trip on the freeway once in a while. I'll keep an eye on it.

 

[ldmack3]

@7bdiver I filled my tranny with 40w to spec, as per TM.
All was fine until I ran it on the highway at speed for two hours. It was puking oil, rust-proofing half of the truck. I did not think tranny fluid; I thought major engine oil leak at first. But engine was dry. Well...dry-ish..you know what I mean.

Clearly spit oil out of the bell housing.

Clutch (brand new) started slipping on the way home. 10 cans of brake cleaner later, that at least seemed resolved.

Pro tip: If you spray brake cleaner into the bell housing from below while laying underneath the truck with the engine running (because you want to hit ALL of the clutch) and are NOT wearing safety glasses, a hat and a raincoat, you did not think ahead.
Anyhoo, the oil level in the tranny seemed to settle where it likes it and has not even dripped since.
These trucks do have personalities.

I'm sorry but I'm missing your point. Did you over service it or did it just "self-adjust" until it was happy?
I need to change mine and am researching what seems best.

 

[7bdiver]

One thing I forgot to mention is that I live up on a mountain and went up and down steep hills repeatedly after changing my oil. I filled it all the way to the fill hole.

Wouldn't it have leaked the same as if the oil expanded with heat?

 

[cattlerepairman]

I'm sorry but I'm missing your point. Did you over service it or did it just "self-adjust" until it was happy?
I need to change mine and am researching what seems best.

I serviced it to TM specs and it "self-adjusted" after that.