Bingle

So, the stock t-case mount gave up on me and I'm looking to replace it with one of the "bomb proof" or heavy duty type mount. Probably.
The problem arises in that ALL sites that sell that type of mount claim that they fit '79-95 gear drive cases (check, got that) and '82-95 4cyl crossmembers (drat, I have an '81).
So I find the stock rubber mount and it fits '81-'83 ????
So what's the deal here guys? Something weird with the '79-81 crossmembers? I get that '79-80 were all 20R + 4 speed trans trucks and I'm under the impression that some or most '81's were 20R 4 speeds.
Mine IS the factory SR5 22R + L50 5speed. (I'm pretty sure it's the L52 now, but am 100% sure that it's still an L trans)
So, is my crossmember the '82 style for the 5 speed? Is there a difference??
Also, anyone with experience with the heavy duty style mounts, are they super noisy or just a bit more vibration at high speed? Is it even worthwhile or should I just get a stock replacement and be done with it? I have already replaced the body and suspension bushings with Poly and have poly motor mounts, so I don't know that it would really make much difference towards "in cab noise". It is by no means quiet or smooth riding as is.
Thanks for the help!

muddpigg

iTrader: (1)

if your running single stock case, I'd assume a stock mount would be fine. I'm dual with 4.70 in rear case; bomb proof mount stopped a good bit of the drive train slop in dual low and obstacles. Before that I ran 2 stock mounts and modified engine mounts. Just my thoughts.

Bingle

Yeah, I'm running a single stock setup on the T-case and I don't wheel it often, but when I do I tend to flog it pretty hard. I was figuring that the cost of the OEM vs HD mounts were pretty close to the same and if I'm replacing it might as well go HD, right?

You make a good point though and my currently torn mount may very well have been the original mount, so the OEM must not be "weak", just not up to the task of duals/4.7's etc. I'll probably just get an OEM replacement. Also, I'm not 100% sure yet that it's torn, I was snow wheeling and a couple times ended up with the shifter leavers pushed up against the side of the trans tunnel. Had to grab R to torque the trans back to where it belonged so I could get at 1st again.

I do feel that the main question still stands though. My impression has always been that the 79-83 trucks were all interchangeable/the same other than minor things like square/round headlights and changes in the gusseting on the SFA's. Thought that putting a 22R + L series 5 speed into a 79-80 20R + 4 speed was a bolt on affair. The crossmember difference just seems weird to me and has my curiosity up. I MUST KNOW THE ANSWER!!
I'll try poking around on marlin and pirate some more and see if I can't find the answer. I'll post up if I find more info.

muddpigg

iTrader: (1)

don't have much info on years before 2nd gen truck/1st gen 4rnr.

Prolly a good idea to check motor mounts to especially drivers side if you got the much drive train shift. Don't get me wrong t-case mounts are important but motor mounts are too. If tranny and t-case are bolted to motor.

if you plan to go duals one day might be cheaper to pony up for HD t-case mount now.

Bingle

Good points. I already have poly motor mounts that have "lock tabs" built in. Keeps the upper and lower from separating even if the poly did tear. I can see some very minor scratch/ding in the metal/dirt/grime around the tab from this last wheeling trip but the poly seems just fine. Will totally double check it when I dig into the trans mount though.
Duals are not in my future. They are cool and I have thought about them in the past, but I really don't see myself ever using them, and certainly not enough to justify the cost.
HD mount seems like good "extra insurance" choice, but the claims of requiring an 82+ crossmember worries me. I don't want to spend $300 on a crossmember upgrade I don't really need just to run a beefier mount

muddpigg

iTrader: (1)

I agree 100% bout upgrading it not needed. Something seems of though with that much shift. These types of mysteries are the fun one

dropzone

iTrader: (6)

When I replaced my t/c mounts when I upgraded to duals in my 81 a friend recommended I take a look at the motor mounts, they too were shot.

something to keep in mind that if you go to the 'bomb proof' t/c mount and motor mounts you will notice some more vibration being transmitted to the frame. I ran two 4xinnovations t/c mounts and the T-G engine mounts
and definitely noticed more vibration.

I noticed no difference in t/c mounts in 1st gens. I had t/c's from 79-87 at different times

Bingle

So, I just ended up ordering up the stock style t-case mount and will definitely be giving my motor mounts a close inspection while I'm at it.
As stated before, the motor mounts are "upgraded". They're poly with "safety tabs" (older NWOR product IIRC) and I did definitely notice more vibration transmitted after I did them (IIRC I did those at the same time I did the poly body bushings, but that was 10 ish years ago).
At this point the curiosity is over why Marlin, LowRange, and others (everyone I've seen selling them) claim those HD t-case mounts won't work on an '81 or earlier crossmember??? What changed between 81 and 82 trucks? Makes no sense to me but there's likely a good reason, especially if Marlin claims there's a difference, IMHO.