O/T Chev 4X4 transmission question

old · Jan 23, 2010

Ok checking the oil level in my Chev 4X4 tranny rear end and front end. So on the transmission does the transfer case how its own oil or are the transmission and transfer case the same oil??? I did find the front axle a tad low and reason I;m checking is the last time I had it in 4 wheel drive I noticed a bit of a noise that should not be there.
Thanks

BANDITFARMER · Jan 23, 2010

What year is the truck and what transmission and transfer case is in it?

axlehandle · Jan 23, 2010

they take there own oil make shure you put the right oil in it

old · Jan 23, 2010

1980 4 speed. Cast iron case on both but not sure tranny number or transfer case numbers. It is in what is call a heavy half with a 350 up front

Russ from MN · Jan 23, 2010

I had an 87 and there was a hole big enough to stick your finger in and check the chain tension and the oil at the same time. I have heard the chain slip under load on a Chevy and that is a distinctive sound, but they always make a little extra noise in 4-wheel.

Old Ford Mechanic · Jan 23, 2010

That truck should have a New Process chain driven transfer case.It has a plug in it requiring a 1' wrench to remove if i remember correctly.The check plug is on the rear of the transfer and on the drivers side.It is located at about the mid point of the housing.Add Dextron in it until it is full to the bottom of the plug hole.

old · Jan 23, 2010

Takes a 5/8 wrench to pull the fill plug and as per the Book it takes 80W-90 oil but I use 85W-140 in my stuff. Automatic tranny oil is made for automatic trannys not heavy duty truck transmission like this one which is the extra heavy duty set up not the run of the mill set ups for a Chev. This tranny is still an old school one and is a bear to shift unless you hit it just right or double clutch or do as I do most of the time and forget I have a clutch pedal. From what I was told when I got this truck it is the gear type transfer case not the chain drive one also

D Slater · Jan 23, 2010

They were still putting a new processes 205 gear drive transfer case in some trucks in 1980 and a 203 full time transfer case. They use different types of oil. If the transfer case shifter has low lock and high lock its a 203. If the transmission has a grany low its probably a # 465.

old · Jan 23, 2010

Has low lock then N then 2 wheel drive then high lock. Tranny has granny and the knob says
L-3
1-4.
This truck also has 307 gears in the rear end so it does do well on gas for what it is at around 16-17mpg

chevytaHOE5674 · Jan 23, 2010

Sounds like a 465 tranny with a 205 Tcase behind it. Common run of the mill setup for many many years of chevy trucks.

bradk · Jan 23, 2010

Old,Sounds like ya have the 205 w/gear drive t-case and it requires gear lube.

One tough mutha of a t-case!

old · Jan 23, 2010

Ya that is why when I found this old truck I jumped on it. Been a real work horse for me and has hauled some things that I probably should not have hauled. Been scaled out at over 14,000lbs a couple times

D Slater · Jan 23, 2010

Sounds like you have the 205 and the same oil can be used in the transmission and transfer case. Was thinking the 205 shifter had 4 wheel drive on it, but can't remember for sure. The 203 transfer case had two shift positions on each side of neutral.

JDemaris · Jan 23, 2010

There wasn't any transmission put into 1980 Chevy pickups that shifted hard enough to need double-clutching. That applies to older HD sliding gear transmissions. Not collar-shifted transmissions like you've got. I assume you've got the Muncie SM-465. Only sliding gear with no synchros is the granny low.

Transfercase, if cast-iron is likely the 205. It does not have near as low a low-range as the chain drive 208 or 241. Cast iron 205 only has a 1.9 to 1 low range. Aluminum 208 has 2.6 to 1 in low, and the 241 (replaced 208 in 1987)has 2.7 to 1 in low.

As to gear oil, the 90W versus thinner Dextron has nothing to do with being heavy duty, or not. If that were true, there would be an alful lot of hugh HD Allison industrial transmissions blowing up.

Leland2 · Jan 23, 2010

around here a lot of guys put 10w30 motor oil in them bacause it flowed into the bearings and chain better

Billy NY · Jan 24, 2010

Rich, I have the same set up, though my 1980 was an auto, when that went, I found a complete 4 speed set up from another truck with about 30,000 miles, that had rusted out. The fluids were still clean in both the trans and the transfer case. I forgot what NP t-case it was, 4wd lo, neutral, 4wd hi, 2wd, I think, thought they are clearly tagged, this one has factory spicer lock out hubs, not the full time hubs and the transfer case that just had the illustration of the wheels on the knob, you know the gas guzzler one, I always liked the part time better.

When I installed the 4spd and transfer case, I drained out the old lube and put in 85W-140 cling, it's been in there since '94, the truck has sat, but I did use it to plow snow for many years. One thing is for sure, that drive train, gear driven transfer case, is one tough set up, before I had a tractor here again, I used to head up into the fields, line up small trees with the plow frame and carefully push em over, then drive over em, one way, no going back obviously. I put in the heaviest clutch napa had for it, this one shifts nice, not trouble at all.

old · Jan 24, 2010

Bet if you look at the 4 wheel drive shifter you will find that all the way forward is 4 low, then back one is N then back one more is 2 wheel and then back all the way is 4 high. I have had to use the 4 high on and off here a lot lately because of it thawing on top and being frozen down about 10 inchs so it is one muddy mess here right now

Old Ford Mechanic · Jan 24, 2010

Pardon me sir, As alway's you are correct.

old · Jan 24, 2010

Can not tell you if it was factory but I can tell you it loves to grind when shifting if you do not take your time and do it just right. I can also say this tranny/transfer case set up is very heavy but I know that because I did a clutch in it last summer and boy that was no fun. Either way I got the front axle, transmission and transfer case now full of 85W-140 oil

JDemaris · Jan 24, 2010

I assume you've got the SM465. Super granny low with no synchros. They always shifted kind of hard, as compared to others. No clashing, just takes some added effort. If your's clashes without double-clutching, you've got worn-out synchro rings. I used to think all HD truck transmissions were like that until I got my 92 Dodge diesel with the HD Gertag 5 speed. It shifts as smooth as glass.

As to gear oil in the 205 transfercases, I suspect it has more to do with it's design to hold thin oil and not leak. My 92 Dodge has the same 205 transfer case and it calls for 30W oil when driven below 32 degrees F and 50W when above.
My 69 Power Wagon and my 79 Blazer also have the 205s, but they call for heavier oil. So, same internal parts, but thinner oil called for in the newer ones.

old · Jan 25, 2010

You know I never did get my question answered. So is the transmission and the transfer case one in the same sump I.E. if I fill only the transmission will that also fill the transfer case or the other way around???

JDemaris · Jan 25, 2010

No, they are separate.

old · Jan 25, 2010

Not to be getting on you or any body else but some times I think it is funny how if you ask a simple question here that you end up with all sorts of info that you didn't want or need. As in my question about the tranny/transfer case oil. I see it all the time on the forums but hey at least I did get my answer even if it took a few days LOL

JDemaris · Jan 25, 2010

Hey, you get what you pay for. On these forums, seems the bulk of responses are to other responses, and not the original question. I'm as guilty of that as anybody.

As to the trans case and transfer case - they run with different fill levels, so I suppose that is why they are both sealed and separate. And in some situations, they both use different oils also.

old · Jan 25, 2010

Ya I think on this one the seal between the 2 maybe bad since it seems like the transfer case is over full and the tranny was low. Oh well it is an old farm truck not pretty but when I need something hauled it does the job and does not complain LOL

O/T Chev 4X4 transmission question

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