5 Speed 4x4 Swap From a 92 250 To 91.5 350

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5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Dodge Dually Nut » Sat Sep 24, 2016 6:53 pm

Hello All

I'm attempting to put a 5 speed 4x4 and t-case trans out of a 92 250 in a 91.5 350 with the 8 in frame.Both trucks are Cummins diesels. The 91.5 had a 3 speed auto and was 2 wheel drive. The 91.5 350 will become 4 wheel drive but not right now. I'm just trying to do the trans swap first. I've got the auto out and I'm pulling the 5 speed now. I've hit two bumps in my plan. I've figure out that the tunnels are not the same. My 350 is narrower than the doner 4x4 250. Since I'm not going to complete the front end swap right away it looks to me that if I skip installing the lever for the t case shifting the new trans ought to go into the narrower tunnel.

Am I Right????

The other problem is the trans mount cross member is way different between the 2 trucks. Is it different because of the auto to 5 speed or is it 91.5 to 92 design change or is it because of the t-case. It looks like none of the holes in the frame are going to line up with the new cross member. And the really bad design with the trapped bolts on the top frame rail that are held in by the cab.

Help!

I'm contemplating pulling the cab to get the new holes drilled. Is there an easier way?

Also I know where there is a 2 wheel drive 5 speed for sale. Will it work with my old cross member from the 727 auto trans? I have to drive this truck to Florida from Michigan this coming Friday. I'm pulling a 8000 lb trailer which is why I decided to go with a manual trans. If It can be a bolt in I'll use it for my trip and pull it when I do the front end swap.

Look forward to some advise
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Philip » Mon Sep 26, 2016 5:48 am

To drill the upper frame holes use a long drill bit and do it threw the bottom rail holes. Fastenal sells long 7/16" drill bits.

The 2WD trans should work with your auto cross member.
93 W350 Club/cab w/duals, buckets & console, B&W flatbed, G56, 6 spd, 3:07 rears, gages, HX40/16, 4" exhaust, 6X.018 sticks, rear air ride suspension
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Dodge Dually Nut » Mon Sep 26, 2016 6:40 am

What about drive shaft lengths. Will it end up longer or shorter than my 727 auto? I was trying to install current 4x4 5 speed trans last night with the bell housing on. It accrued to me to try taking the bell housing off and put it on first then put trans in 2nd. Will the throw out bearing stay in the right position for trans insertion? I couldn't get up high enough for the input shaft to go in. This should give me a possibility of getting it in. Comments?
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby CumminsPower59 » Mon Sep 26, 2016 11:02 am

Dodge Dually Nut wrote:Hello All

I'm attempting to put a 5 speed 4x4 and t-case trans out of a 92 250 in a 91.5 350 with the 8 in frame.Both trucks are Cummins diesels. The 91.5 had a 3 speed auto and was 2 wheel drive. The 91.5 350 will become 4 wheel drive but not right now. I'm just trying to do the trans swap first. I've got the auto out and I'm pulling the 5 speed now. I've hit two bumps in my plan. I've figure out that the tunnels are not the same. My 350 is narrower than the doner 4x4 250. Since I'm not going to complete the front end swap right away it looks to me that if I skip installing the lever for the t case shifting the new trans ought to go into the narrower tunnel.


You will need to cut out the small hump floor section and graft in the larger section from the donor if it is in good shape.

Dodge Dually Nut wrote:The other problem is the trans mount cross member is way different between the 2 trucks. Is it different because of the auto to 5 speed or is it 91.5 to 92 design change or is it because of the t-case. It looks like none of the holes in the frame are going to line up with the new cross member. And the really bad design with the trapped bolts on the top frame rail that are held in by the cab.

Help!

I'm contemplating pulling the cab to get the new holes drilled. Is there an easier way?


Don't worry about the different cross members, use the one from the donor (5speed). As for location, one way to do this is leave the clutch out of the transmission and mount it to the engine. You can leave the cross member attached to the transmission or remove it during mock up...either way you can get the correct placement for the new holes. Mark the holes, pull the trans back out and drill away. The other way is leave it in and drill the holes. If it were me, I'd mock things up, remove everything and have the room to work without the transmission in place.

Dodge Dually Nut wrote:What about drive shaft lengths. Will it end up longer or shorter than my 727 auto? I was trying to install current 4x4 5 speed trans last night with the bell housing on. It accrued to me to try taking the bell housing off and put it on first then put trans in 2nd. Will the throw out bearing stay in the right position for trans insertion? I couldn't get up high enough for the input shaft to go in. This should give me a possibility of getting it in. Comments?


Put the clutch assembly on the flywheel, align the input shaft splines, then put the whole trans on with the bell housing attached. It'll take some wiggling to find the sweet spot. One thing you can do is put the transmission in gear so you can rotate the output shaft, thus rotating the input shaft so it finds that "sweet spot" and slides in place. As for the drive shafts, are the trucks the same wheel base? If so, you should be able to re-use the donors drive shafts no problem. If they are different, then they'll obviously have to be shortened/lengthened.
Ike

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04 VW Jetta Wagon TDI 5speed
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby thrashingcows » Mon Sep 26, 2016 6:29 pm

If you look in my build thread you can see how I put in a removable tranny tunnel in my crewcab, as well as drilling my 2wd crewcab frame for 4wd. But as mentioned you will need to use the larger 4wd trans tunnel to get the 5spd/np205 in place.

I agree with the other suggestions of once the trans tunnel is changed then toss on a new set of trans cross member bushings and then install the cross member and use it's placement to mark for the holes to drill. I used a short 90* air drill with a shorty drill bit to get the upper bolt holes drilled in my frame.
1984/93 Dodge Crewcab, W350, 1 Ton SRW, long box, 330K Km's, M&H spacer, 366 spring, fuel pin to deep side, 14cm housing, Piston LP, PS IC, Isspro Boost, Pyro and tach, NV4500, 29 spline NP205, 3.54's.


Check out the build....http://www.dieseltruckresource.com/dev/ ... 05923.html
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Dodge Dually Nut » Tue Sep 27, 2016 5:33 am

Thanks for the info.

I did get the 5 speed trans to go in last night with the narrow tunnel. I bent the body seem that is a few inches from the fire wall up as much as I could. Could of done a better job of it if I had thought of it before I put flywheel and clutch on. There was no way I was going to mess with those bad boys again. I felt like I was risking serious bodily harm when I was putting them in. I'm on my back doing this job. I don't have a lift and I'm no spring chicken. Turned 61 this year. I've never used a floor jack for a flywheel and pressure plate before! So the key to getting it in with the narrow tunnel is doing the bell housing first. It makes it real easy to get at the top mounting bolts. I still was getting to to scraping issues with the shifter bump on top I had to elongate the new nicely cut hole in the tunnel to allow the trans to go up enough before the input shaft was engaged. Any way its IN! I've got the cross member mocked up and with the top of the transmission behind the shifter hitting the tunnel it looks like I'm up just barely high enough. I've got new trans mount rubber bushings coming. Pick them up tonight. If it won't go up enough it looks like all I'll need to do is cut down the top and bend it up some. I'm trying to avoid doing the entire tunnel right now because I'm leaving on Friday and the truck is shredded!!! I'll post again tomorrow morning on what happened with the tunnel.
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Dodge Dually Nut » Tue Sep 27, 2016 5:55 am

What do you guys do about the trapped bolts on the top frame rail for the trans mount support. I could cut them out and have the new ones go the other way and be shorter so they don't push on the cab. If that's what you do what length bolt works out? Or was thinking about removing the 4 cab bolts to the frame and jacking it up about a inch or so to get the old bolts out and slip them in to the new holes. Comments?
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby CumminsPower59 » Wed Sep 28, 2016 12:53 pm

Dodge Dually Nut wrote: Or was thinking about removing the 4 cab bolts to the frame and jacking it up about a inch or so to get the old bolts out and slip them in to the new holes.


That's what I would do.
Ike

91 W350 SRW, 3.07's, NV4500, 370's, THD LPPP, Super HX40, 2nd gen IC swap, BHAF, Isspro's, 2" lift, 285's on 3rd gen 17"'s.
04 VW Jetta Wagon TDI 5speed
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Dodge Dually Nut » Wed Sep 28, 2016 2:07 pm

Great! I'll try that tonight. I got two of the bottom holes drilled last night but I had the drill bit stall and the drill motor torqued out of my hands and bent my thumb back. I'm in rough shape today. But I'm leaving in 3 days. Hello advill!!
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Farmboy » Fri Oct 07, 2016 11:09 am

So did you make your departure date?
1990 W350 4X4 NOW INTERCOOLED 5-speed. Boost/Pyro. Few light tweaks to the pump. Now a dually with an aluminum flatbed!!
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby Dodge Dually Nut » Fri Oct 14, 2016 1:24 pm

No I didn't. I got on the road on Monday evening. I made it to Tennessee for a meeting for work and then had to sit there for two days waiting for the Hurricane to get by Jacksonville Florida. Made it back on Tues evening. Truck did pretty well considering what I did to it. Diesel dragged a 7500 lb trailer thru the mountains in Tennessee.It didn't miss a beat.
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Re: 5 Speed 4x4 Swap From a 92 250 To 91.5 350

Postby 1STGENFARMBOY » Mon Oct 17, 2016 2:12 pm

See that is what I like about these old cummins trucks, you can mismatch and throw things together over a weekend and drag a trailer across country the next day without any problems.


Dar
93 W250 STD CAB, AUTO 3.55, GAUGES, 80HP DDP STICKS, DENNY T ,16CM HOUSING, 60MM GILLETT, VE MAXED,BHAF, BHFF, 366 SPRING,P/S INTERCOOLER, TIMS COOLER TUBS, TIMMING 1/8 BUMP,4in TURBO BACK TO DUEL 5IN STACKS,33 12.50 BFG, HOLLEY BLACK, CONVERTER COOMING.
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