Anyone here running a Tremec 4050? And other manual with overdrive conversions

[plumber mike]

I’ve been playing around with my 1990 GMC Jimmy. I’ve always enjoyed the simplicity and frugality of the square body style, but always the same issue with everyone I’ve owned. No overdrive. So I start research on a swap. NV4500 would be great, but they’ve become quite pricey and this truck won’t be getting beat to the point of needing 1 ton axles and a bulletproof drivetrain. So I thought a NV3500 would be ideal.....and then I noticed the Tremec. I haven’t heard much about it.....so I come to the folks that I know are in the know.

Let’s hear some overdrive row your own stories.....preferably with pics.

 

[plumber mike]

Gear splitters, Ranger boxes, Gear Vendors unit, or any other solutions are also more than welcome to share here.
Thanks

 

[zoomad75]

I picked up a 4500 for my square. Horse traded for it with a 4l80e I had a few hundred in. I've got a fellow square body buddy in Denver that finds them regularly in pick and pull yards for $200 or less. I think at any given time he has two on hand. I'm picking up one from him tomorrow for buddy in Phoenix.

If you think a 4500 is pricy take a look at the price of the tremec. The 4500, even buying a rebuilt one is less than half the price of the tremec.

My buddy Larry (blue 78 k10 with a 8.1 and camper) has bought two, one new old stock and the other rebuilt through some shop in Texas for under $1500 each time.

Part of the expense is adapting the 4500 to the square body. Most common route is an advanced adapter bell housing and external slave bracket. I'm going to run the stock gm bell housing for an internal slave clutch setup. Those were used on the 96 and later trucks. It takes some some adapters for the clutch hydraulic line to hook up but it provides a system with more oem parts for serviceability.

I'd start watching your local pick and pull yards for 3/4 ton and 1 ton trucks from 92-99 and pull one.

 

[toastyjosh]

The NV3500 is fine, it does not have the super low first gear that the 4500 has but still a good trans.
Really is whatever 3500,or 4500 you can find for the cheapest.

 

[zoomad75]

The NV3500 is fine, it does not have the super low first gear that the 4500 has but still a good trans.
Really is whatever 3500,or 4500 you can find for the cheapest.

Keep this in mind about the 4500 when swapping with a factory 465 Muncie. They are the same length from the front of the trans to the t-case mounting flange. When used with a round pattern 241 t-case that the op's '90 Jimmy would have originally, it's practically a bolt in affair that won't require any change in mounting or driveshaft length.

I don't know the specs of the 3500 for overall length.

 

[aardvarcus]

I have done a couple NV4500 swaps, it is also the same length as a 4L60. I love the NV4500, swapped in a 1991 K2500LD and 1994 K2500 Suburban. Keep in mind there are different spline counts for the output of the transmissions/inputs to the transfer case, so if you have a 27 spline now your transfer case might not work. Not that hard to source a 32 spline TC though.

 

[zoomad75]

I have done a couple NV4500 swaps, it is also the same length as a 4L60. I love the NV4500, swapped in a 1991 K2500LD and 1994 K2500 Suburban. Keep in mind there are different spline counts for the output of the transmissions/inputs to the transfer case, so if you have a 27 spline now your transfer case might not work. Not that hard to source a 32 spline TC though.

Yep the 4500 is a 32 spline output. 241's could be had with 27 or 32 spline input, same for the 208's and obviously the 205 could be had either way with 27 or 32 spline input. For the 205 you will need to find the later (and rarer) round pattern case that will bolt right up to the 4500. An earlier 205 case with the figure 8 mounting flange can be made to work with an Advance adapter's output housing for the 4500 and does require cutting off something like 4 inches of the 4500's output shaft for the adapter to work. Having gone through that once on my buddy's truck I'd search for the correct round pattern case instead.

If you don't find the correct 32 spline input they are available to buy separately to swap into the case you have. It's not hard to do either.

 

[plumber mike]

Thanks everyone for the participation and information. I’m going Monday to look at a NV4500 from a 92 Chevy. External slave included. They want $900. Seems a little high from the wrecking yard...but I live in the sticks. Im willing to pay more to save any fab work, adapters, new driveshafts etc.
Any more words of wisdom on this is appreciated. I didn’t think the Chevy ones had the 5th gear loose nut issues the dodges had. Is that correct?

 

[zoomad75]

Chevy did have the same 5th gear nut issue.

The external slave system is workable as is, but since the slave is on the passenger side in a '92 truck it puts it real close to the squarebody front driveshaft at full compression. I've seen some use the stock '92 bell housing without any issue, but I guess it really depends on how you wheel the truck. With that version of trans the simplest route is forking over the dough for the AA bell housing. You can use stock squarebody clutch slave (driver side mount) and it will be out of the way of the front driveshaft.

Another option is to have the hydraulic clutch bell housing for an SM465 trans in a squarebody and having it redrilled to match the mounting points for the NV4500. Success really depends on the accuracy of the bolt locations and making sure the trans input shaft centerline is on the same centerline of the engine crankshaft. This is where the AA bell housing starts looking good if you don't have the ability for the precision required to do that right.

 

[plumber mike]

Chevy did have the same 5th gear nut issue.

The external slave system is workable as is, but since the slave is on the passenger side in a '92 truck it puts it real close to the squarebody front driveshaft at full compression. I've seen some use the stock '92 bell housing without any issue, but I guess it really depends on how you wheel the truck. With that version of trans the simplest route is forking over the dough for the AA bell housing. You can use stock squarebody clutch slave (driver side mount) and it will be out of the way of the front driveshaft.

Another option is to have the hydraulic clutch bell housing for an SM465 trans in a squarebody and having it redrilled to match the mounting points for the NV4500. Success really depends on the accuracy of the bolt locations and making sure the trans input shaft centerline is on the same centerline of the engine crankshaft. This is where the AA bell housing starts looking good if you don't have the ability for the precision required to do that right.

Thanks for taking the time to respond. I’m...at best...a backyard parts swapper. The truck has somewhere between a 4” and 6” lift right now. Plus someone installed some spacers to drop the Tcase cross member. I say it won’t be wheeled hard, but I know I don’t know. It might.

I’ll have the original 465 hydro bell and the NV4500 bell. The one should give me a template/measurements to drill the other. Sounds like I won’t be out anything but time if I screw up and need to pony for the AA bell.

I’m reading up on Larry’s thread in hopes of keeping redundant questions to a minimum. Any other builds you guys know about with decent technical info would be much appreciated.

I’ll hope to get the pic uploads figured out before I dive in. They used to work years ago, but now everyone I try is too big.

Thanks again.

 

[plumber mike]

@zoomad75
Do you have a thread for your K5.3 that was mentioned in Larry’s thread?

 

[zoomad75]

Thanks for taking the time to respond. I’m...at best...a backyard parts swapper. The truck has somewhere between a 4” and 6” lift right now. Plus someone installed some spacers to drop the Tcase cross member. I say it won’t be wheeled hard, but I know I don’t know. It might.

I’ll have the original 465 hydro bell and the NV4500 bell. The one should give me a template/measurements to drill the other. Sounds like I won’t be out anything but time if I screw up and need to pony for the AA bell.

I’m reading up on Larry’s thread in hopes of keeping redundant questions to a minimum. Any other builds you guys know about with decent technical info would be much appreciated.

I’ll hope to get the pic uploads figured out before I dive in. They used to work years ago, but now everyone I try is too big.

Thanks again.

Sounds like somebody before you probably used the spacers for the bolts to the t-case cross member and used them to space it down. Pretty common thing to do, but the wrong way to do it. If they are the round spacers I'm thinking of, they are actually supposed to go between the bolt head and the inside of the frame to give the bolt enough length for solid clamping force. If they are under the frame now, there is a fair bit of leverage on the bolts now to make them easy to break. Use some flat stock or similar material to make the spacer out of and take the round ones out and put them back on top of the inside of the frame.

You have the right idea on the use of the old bellhousing with the new one as a template. Just make sure to be precise.

As far as builds with the 4500, Larry's documented it on his 78 and on his Suburban quite well. The 78 does show both ways he did it on that and the Suburban takes the easier route since it already had the round pattern t-case with the 241.

@zoomad75
Do you have a thread for your K5.3 that was mentioned in Larry’s thread?

I've got my main build thread over on CK5.com. It's up to 91 pages, but I've also used it to keep track of a lot of the smaller weekend stuff we've done and the camper build as well. Here's the link to it.
My Build

I'm in the parts procurement phase for mine right now. The 8.1 is sitting over at Larry's place and the 4500 (with internal slave setup) is tucked into my garage at this point. I've managed to find the right Hydro clutch and Hydroboost brake pedal assembly this summer too. The plan was to swap this winter but life has had a way to throw a wrench into those plans. The truck runs fine as is despite the lack of power with the camper. It will make it another season without anything more than maintenance at this point.

We've got a fellow Squarebody nut in Denver that picked up a 77 K5 and FWC camper combo that has swapped in an L29 454 and nv4500 with the same bell housing you picked up. I've wheeled with him over the Rimrocker trail to Moab and two great trails in Moab and at least with his 6" lift didn't have any issues with the front driveshaft and passenger side slave location. He's got a good build over on CK5 as well.
Ron's 77 build.

 

[plumber mike]

Thanks. I seem to remember my old 465 burb’s crossmember bolted up the way you describe. I remember it that way because I thought it a terrible snag point that would bend the bolt. The poly engine mount inners should be here next week so I’ll plan to address it then. Might even have a tranny for Christmas. Tentatively planning to use the 465 bell if the drilling goes well. Plan B is the 92’s 4500 bell and hopefully get the assumably longer line from that truck. I was crawling around under it today and it looks like I should have plenty of clearance to the front driveshaft.

I’ll head over to CK5 and check out yours....if I can remember my password. It’s been a while.

Thanks for all the information.

 

[plumber mike]

Are you guys hosting photos on another site? I was hoping to document my shenanigans for others, as many of you have done for me....but I’m worse at computer stuff than I am at wrenching.
Saved the fam some trouble and bought my own Christmas gift.
Picked up that NV4500. Pulled from a 92 K3500. Got the trans, bell, shield, shifter, rubber boot and slave. I suppose I’ll get a new clutch, fresh gear oil and start yanking the 465. I’ll take pics along the way, and hope one of my kids will figure a way to get them up here.
I also got a nice dent free rust free GMC truck tailgate for the jimmy. Minor details, but glad it’ll stay all GMC.

 

[plumber mike]

Why this one loads, I have no idea