5lm60 to THt400 swap questions

[highperf4x4]

I have a 1990 GMC K1500,5lm60 5speed and an NP241 transfer case.

I'm going to do a swap to a TH400. From what I've searched out on here so far, the 32 spline count for my t-case should be correct for the TH400? I need one with a 2 3/8" output shaft?

Now for my stupid questions. Since I've read that some of the 3/4 ton trucks came with TH400s will they be a direct fit for my t-case and adapter plate? Did the 3/4 tons have the same NP241 transfer case as mine? Will I be able to make my existing crossmember work? If not, will the cross member from the 3/4 ton work or maybe the crossmember from any 1/2ton auto?

I have a line on a TH400 from a 90 model 3/4 ton if it will work.

If this is all hogwash does anyone have an idea of what truck has the TH400 I need?

 

[TylerZ281500]

all 4wd 400s are the same, tcase will bolt up and the cooler lines should pop right now

 

[highperf4x4]

I thought there were different lengths on the tailshafts of the 4x4 TH400s?

I'll have to add cooler lines. I already have a radiator from another truck with a tranny cooler in it. I also have the flexplate that came with my 383 rotating assembly and a stall converter and shift kit on standby. I guess I'll have to use a universal cable actuated floor shifter as well if anyone has a suggestion on a good one.

Still looking for ideas on what crossmember might possibly be a bolt in situation as well.

Thanks for the info.

 

[FastOrange]

I thought there were different lengths on the tailshafts of the 4x4 TH400s?

I'll have to add cooler lines. I already have a radiator from another truck with a tranny cooler in it. I also have the flexplate that came with my 383 rotating assembly and a stall converter and shift kit on standby. I guess I'll have to use a universal cable actuated floor shifter as well if anyone has a suggestion on a good one.

Still looking for ideas on what crossmember might possibly be a bolt in situation as well.

Thanks for the info.

I use a B&M Unimatic with my TH350 swap, works okay.

I would just see if you can re-use the stock crossmember, might have to drill some holes on the frame, no biggie.

 

[highperf4x4]

I'll probably do that. I'm not afraid to do some drilling lol

I'm having trouble locating a th400 tranny right now. The local performance guys want 850 to build the tranny for what I need if I bring the tranny to them and do the install myself. By the time I buy a used tranny and pay them to build it will be as much as just ordering one from Hughes or Monster.

 

[TylerZ281500]

we had a 96 tahoe that some people 400 swapped, crossmember was in the same spot they used the stock shifter just a different location, stock cooler lines threaded right in, as well as the tc bolting to the stock flywheel and so forth.

i dont think there was any difference but i could be wrong i know that 2wd vs 4wd was very different.

ive personally never liked monster, everyone here seems to like them but ive exploded and had way too many issues with their stuff. for 700/4l60es and 80e i go with pro built, otherwise my 400 stuff i usually take to a friend who built old BOP 400s for racing and im not sure what stuff he uses.

 

[highperf4x4]

My truck is a manual now so I don't have a column shifter or cooler lines yet. Not sure what the crossmember for the 5speed will do but I'll see if I can make it work.

I don't actually know much about Monster Transmissions. I'll do some research.

 

[TylerZ281500]

when we swapped a 5 speed to a 700r4 it ended up in the same location, and the 400 swap from a 4l60e was the same location as well. the base of the line b&m floor shift adjustable works great we have one in the mud truck and our friends ex 5 speed blazer. oil cooler is simple to do as well

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[polar]

I know the 4l60e and 700r4 are pretty much the same length


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[highperf4x4]

Well, I pulled the trigger. Here's my new $200 TH400. lol

Now I just have to get it rebuilt.

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