Author Topic: TH350 Mount/Crossmember Problems  (Read 12955 times)

Offline blazing816

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TH350 Mount/Crossmember Problems
« on: September 26, 2013, 12:32:51 pm »
Okay so long story short I notice that my trans is mounted incorrectly. The top is touching the floor already (I mean I can barely put my hand between floor and top of trans it seems) and there is no rubber trans mount bushing between the cross-member and the trans. The RPO codes state that the truck came with a 700R4 originally (now a TH350 I believe). However, what else is different is that it is a 1986 and it has a Dana 44 front (should have a corporate 10 in front for that year I thought). So I have attached some pictures of the cross-member and the trans where it mounts. If someone has insight or can show me the correct cross-member, or something that I need. Also the RPO codes and VIN state it was a 4x4 cab, so it is not a low hump high hump issue. It is only attached by two bolts and anytime the engine rocks it throws side to side torque on those bolts....don't think its going to last. PLEASE HELP......THANKS



« Last Edit: September 26, 2013, 12:50:39 pm by blazing816 »
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1988 Chevy R20 Scottsdale Crew Cab (350/TH400/4.56)

Offline blazing816

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Re: TH350 Mount/Crossmember Problems
« Reply #1 on: September 26, 2013, 12:34:56 pm »
Also here is a pic of the interior....just incase it is a hump thing (ill try and get a better one after work). But all the bolt holes and everything is there for the transfer case shifter.

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1988 Chevy R20 Scottsdale Crew Cab (350/TH400/4.56)

Offline pholliday1

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Re: TH350 Mount/Crossmember Problems
« Reply #2 on: September 26, 2013, 03:25:03 pm »
Sorry I don't have a pic for you. My guess............ is that this cross member and front axle came same donor (truck 70's) you have a double droop cross member you either need the straight or single droop.. Def. looks odd though.
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Offline blazing816

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Re: TH350 Mount/Crossmember Problems
« Reply #3 on: September 26, 2013, 03:31:33 pm »
Yeah its different, because the cross member bolts to bottom of frame rail and it looks to be even to the sides in the middle. So I do not think a straight a crossed one would work either (basically even with double drop where mounts to frame and trans look to be level with each other.)

However I did find these....looks like mount under frame rail and are a little lower where trans mounts. One looks more of a drop then the other. Can any one confirm which I need????

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=271277226886
http://www.ebay.com/itm/261288484173?item=261288484173&viewitem=&vxp=mtr
« Last Edit: September 26, 2013, 03:42:27 pm by blazing816 »
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1988 Chevy R20 Scottsdale Crew Cab (350/TH400/4.56)

Offline blazing816

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Tansmission Crossmember Solved
« Reply #4 on: October 25, 2013, 08:00:18 am »
Okay so I was having issues finding out what the POs did to my truck as the transmission was up hitting the floor pan (with a 4x4 high hump) and was bolted directly to the crossmember with no rubber mount.

Here is the pic of what it looked like:


So I wanted to post my finding, just in case anyone else is/was having problems, because it took me awhile to figure out what I needed. So here is the story, I have a 1986 Chevy K10 305 with a TH350 trans. I knew the trans was mounted wrong so I figured it had the wrong crossmember, but when I started doing research I found that the 86 k10 4x4 only used one crossmember really and it was the one I had  :o . So back to the drawing board, I looked at my RPO codes and the truck originally came with 700r4, okay PO change trans, I was on to something. Further inspect I realized I had a Dana 44 in the front (86 should have a 10 bolt), okay PO changes axles. Then I remembered when me and buddy put the reman motor in, we could tell the old motor was an older motor too from the late 70s - early 80s.

So long story short I assumed that the TH350 was from late 70s early 80s, so I picked up a 82 trans crossmember, and got the two piece trans mounts for it (had to order them and tell them I needed it for an 83 because the 86 is a one piece completely different mount). Well they did not come with the bolts, because they assume you are reusing yours, I could do that because someone hillbilly mounted mine. So more research and I found it uses same bolts as motor mounts. Started putting it together and found that there is no holes in the 86 frame for the 82 member  :o . So I had to drill new ones and of course my "big boy" drill did not fit between frame and garage floor, so I had to jack the truck up one side at a time. Anyways got it together, fits right (dropped about 2-2.5" or so), can plug in the 4x4 light plug now, truck as WAY less vibration (rubber mounts help) and is not so loud now that the trans is not touching the cab. And I am sure the driveshafts are better off now that they're at the right angle. Anyways it was tough for me to figure out, so I thought I would share my short version of my story.

Here's was pics of it completely bolted up:






« Last Edit: October 26, 2013, 01:24:21 pm by bd »
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1988 Chevy R20 Scottsdale Crew Cab (350/TH400/4.56)

Offline rich weyand

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Re: TH350 Mount/Crossmember Problems
« Reply #5 on: October 25, 2013, 07:38:27 pm »
Nice work to puzzle that out!

And you have an oil-wet pan on the TH350.  That's good.  If it ever stops leaking, you'll have to pull it and see what's wrong with it.  ;-)
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift

Offline blazing816

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Re: TH350 Mount/Crossmember Problems
« Reply #6 on: October 29, 2013, 02:30:22 pm »
And you have an oil-wet pan on the TH350.  That's good.  If it ever stops leaking, you'll have to pull it and see what's wrong with it.  ;-)

Yeah I had the pan dropped cleaned, new filter, gasket and new dipstick when I bought the truck thinking it was trans. But all that is actually oil, I put a reman motor in and it has seeped a little ever since I put it in, but never have to put oil in it between oil changes, so I just don't care....lol.
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1988 Chevy R20 Scottsdale Crew Cab (350/TH400/4.56)

Offline rich weyand

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Re: TH350 Mount/Crossmember Problems
« Reply #7 on: October 29, 2013, 04:39:28 pm »
It's the truck version of the glass half empty, glass half full argument.

The pessimist sees an oil leak.  The optimist says, "Won't rust."
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift