Thread: OT- How to know what-fits-what on vehicles

I am looking to put manual trans into my Suburban, instead of fixing the kaput automatic. I am not worried about adding clutch pedal mount and linkage and cutting hole in floor. I have received various advice about what years' flywheels, bellhousings, transmissions will or will not mate up with the engine and transfer case.
Is there an authoritative source for such information?

(The veh in question is 1989 Chev Suburban 2500, 4x4, 350 eng,TH400 auto trans.)

Thanks!

The best thing to do is get a donor vehicle. As you get into the job you will be amazed at the number of odds and ends you need beside the big items. Any junkyard will know what years interchange

Hollander Interchange, at your library, perhaps the Reference Section.

Hollander Interchange: The Best Tool for the Right Part

Both of the above posts are "spot on"

Not a big fan of GM, but the TH400 is the simplest, cheapest transmission to overhaul. Far cheaper/simpler than switching to stickshift.

Far cheaper/simpler than switching to stickshift.

Cause not all engine blocks accomodate clutch linkages.

Well, the '67 SS Nova I attempted to put back together required a V8 block with threads not found on other blocks....

It's been awhile, so perhaps I am mistaken.

The TH400 trans choice can be road ready in days. How many weeks do you have scheduled for the other choice?

I have swapped two automatics to manual... in a modern car there is a lot more going on than just swapping parts. One car was one that came with a manual, the other was a total custom job.

Originally Posted by kustomizingkid

I have swapped two automatics to manual... in a modern car there is a lot more going on than just swapping parts. One car was one that came with a manual, the other was a total custom job.

But, of course, being a machinist can speed up the process, or make the difference between success and "get to it...someday".

An 89 GM pickup is not especially challenging to switch to stickshift, but the TH400 could be dropped, overhauled and re-installed in a matter of a few hours by an average mechanic.

I switched a 97 K2500 to stickshift from a 4L80E and it was pretty straightforward. It was using in the midst of installing a 5.9 Cummins and Dodge NV4500 using Dodge hydraulics. I purchased the stickshift pedals, steering column, dash and wiring harness from a wrecker and installed them.

Originally Posted by S_W_Bausch

Cause not all engine blocks accomodate clutch linkages.

Well, the '67 SS Nova I attempted to put back together required a V8 block with threads not found on other blocks....

It's been awhile, so perhaps I am mistaken.

The boss should have been there, just drill and tap. The one that is a pain is in '68 on Corvettes not all blocks have the clutch bell crank pivot boss, about 8" ahead of the bell housing surface and just above
the oil filter seal surface.

Thanks for all the very helpful replies. My logic, if it deserves the name, is that removing and replacing the TH400 will be a good fraction of the work of the swap, repairing the box will cost most of the price of the conversion parts, and will leave me still with gas-guzzling auto which I hate. I may have a donor truck lined up for $500.

Garwood, the 5.9 Cummins conversion is what I really want, but the neighbor with the Dodge in the weeds won't sell it to me.

That is the first time I heard of a Turbo 400 dying, they are pretty much bullet proof.

Find a Suburban message board, there will probably be twenty posts with details and pictures of exactly what is needed. Guarantee your not the first one doing this.

I'd recommend checking out the full size chevy forum there's other guys on there that have done what you want to do.

Not much difference between the suburban and 1/2 or 3/4 ton truck chassis as far as drivetrain goes. Fortunately you have a GM product with one of the longest lasting unchanged transmission mounting pattern out there. Manual 4x4 GM trucks with the NV4500 are out there but somewhat rare, I'm told you can open up the flange hole on a SM465 bellhousing (the very common GM 4-speed with granny low) and fit a Mopar NV4500 in thee but have no way to verify that, if you do you still have to get a GM transfer case mounting flange because IIRC the dodge T-case puts the front propshaft on the wrong side of the motor. If you are concerned about mileage you want to make sure you either get the NV4500 or the newer ZF trans as the SM465 does not have an overdrive gear and I'd imagine regearing would be hellaciously expensive. Another option would be to fit an overdrive module to the back of your transfer case (I'm told Gear Vendors makes good stuff but again, no actual experience with them)

Once you eliminate the internet lunatics who claim they're getting 25mpg running a 454 with 4.88 gears, most anyone who's owned one will tell you the late 80's/early 90's Chevy trucks with a 350 are gas hogs regardless of transmission. I've owned a 92 shortbed 4x4 since new. 4.3 v-6, 5 spd manual, and 3.43 gears. It got a consistent 19-20 on the highway unloaded originally, and gets more like 16-17 under the same conditions now with 250K miles on it. A guy who worked for us for years had a near identical truck, but with a 350, and he always said he never got more than 13-14. We've still got a 2wd 89 longbed 1500 at the shop with a 350 and auto, probably not a 400 trans as it has a lockup converter. Unloaded, that one always got about 13 too. Since a 4.3 v-6 is essentially nothing but a 350 with a couple cylinders chopped off, I've never really been able to come up with any logical reason why there's so much difference in the gas mileage of otherwise identical trucks. Personally, I'd bet you'll end up not gaining more than 1-1.5 mpg at best, and that's a bunch of work for that sort of return.

Is this the R/V suburban? If so I have a similar truck, the R30 (1 ton pickup). It has the 3L80/TH400 setup, and has endured an impressive amount of heavy towing without complaint.

I was kinda bummed about the lack of a 4th gear, had considered getting a 4L80E at one point with a Baummann Engineering driver box to simulate what the ECM doesn't have to give.

However I just stuck with what was proven, I don't drive it enough to justify the expense. Guessing it would have taken me 10 years of regular driving to recoup the investment. Were it me I'd rebuild or trade for a warrantied reman trans and go on with life....unless you like and enjoy tinkering around with vehicles (which is fine too)

Originally Posted by matt_isserstedt

Is this the R/V suburban? If so I have a similar truck, the R30 (1 ton pickup). It has the 3L80/TH400 setup, and has endured an impressive amount of heavy towing without complaint.

I was kinda bummed about the lack of a 4th gear, had considered getting a 4L80E at one point with a Baummann Engineering driver box to simulate what the ECM doesn't have to give.

However I just stuck with what was proven, I don't drive it enough to justify the expense. Guessing it would have taken me 10 years of regular driving to recoup the investment. Were it me I'd rebuild or trade for a warrantied reman trans and go on with life....unless you like and enjoy tinkering around with vehicles (which is fine too)

have you ever used the Baumann trans control? I put a 4l80e in my '90 Chev dually big block. I used a TCI control and have never been too happy with it.

I have switched over 3 vehicles to manuals. I like the control and simplicity and performance I have gotton out of each, but to each his own. The first was a '61 Chevy Bel-Aire (my first car, bought in 1997-daily driver) where I switched the 2spd to a 3 speed with overdrive. Had to switch the column (three on the tree, no hole in the floor for me) which required the driveshaft change (75 to have one cut) and some constructive linkage design, and some wiring for the OD. Well worth it, but pretty messy because I did not have the correct linkages. The second was a 86 honda accord-very easy. Took 2 6hr days and 3 trips to the junkyard, required one half-shaft changed, all cable linkage for clutch and all holes were existing-very nice when done. The last one was my 86 Ford F-250 with a tired C-6. I installed a T-19 in it (no OD) and this was the easiest yet-an afternoon. Tranny mounts were the same, driveshafts were the same, swap the floor pan (bolt in) and took no more time than to swap an identical transmission.
I would find a parts truck of the same vintage, either at a junkyard and do a swap with stock parts-this way there is no cobbling. A NV4500 would be ideal if you can find one, not sure what other options there were but the lighter 5 speed used in the 1/2 ton trucks woudl work, but not sure about how strong of a tranny it is. I woudl look very closely at tranny lengths. It is a chevy, so parts are pleantifull and cheap, so be picky. The manufacturers made both vehicles in the same cabs, frames, etc, so find out before you do anything what the differences are. Go to the boneyard with a camera and a tapemeasure and some paper-know it inside and out and have everything ready. Get the driveshafts out of the doner, or expect to have them cut. You do not want to have this thing sitting in your garage for months, just get it done.
Joe

Originally Posted by moonlight machine

have you ever used the Baumann trans control? I put a 4l80e in my '90 Chev dually big block. I used a TCI control and have never been too happy with it.

Never actually started buying hardware, seemed like it was cheaper than a TCI by a bit and there was an actual guy behind it in case you needed support.