1998 tahoe mystery trans

[Natedawwg]

1998 tahoe 2 door. The rpo code says m30 and by my reaserch that is the early 4l60e and whats in there has no identifying marks but does look like a late 4l60 e from reading on novac trans swap.
My 96 has the m30 tag on the side 4 bolts to the transfer case. The 98 has 6 another reason i belive its a later 4l60e
In the rpo code NP8 says active 2 speed push button 4 wheel. My 1996 is push button but no auto 4 wheel option on the selector on the dash.

So my question would be would my 1996 4l60e and transfer case go into the 98' the trans in the 98 currently is wonky slips. Sometimes shifts nice then after driving dosent wanna grab the clutches
It also wont manual shift into 1 or 2 at all . And i dont have to hit the brakes to shift out of park i belive that is neutral safty switch on the side. Also have no selector. In the pictures im not sure the year or style of t case ive tested it . It does work but service 4 wheel is on the dash. There is also a aluminum box the 96 is correct its above and just left of the brake pedal the 98 is the one hanging and it says 99 tahoe im not sure what that is.

My concern commming from ive heard and experianced horror stories from these trans becase 95 is 1 year 96 97 is another

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[Natedawwg]

These were also found in center counsol. Not sure what they are to or for. The aluminum box is the trans control moduel i belive

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[tayto]

trans control is not a separate module, it's done by the PCM. is your 98 a 1 piece case or is the bell housing removable?

 

[Natedawwg]

Removable. But the rpo code in the glove box says m30 compairing the 2 trucks the 96 is correct/original trans the current 98 is the removable bell housing. So im wondering if i could put my 96 m30 4l60e and transfer case and that silver box or would the computer freak out.

 

[Natedawwg]

Found a recipt. Its a transfercase control module. Its got the np8 rpo code also for the 2 speed auto 4 wheel but im thinking since both rpo codes in the 98 and 96 are m30 wouldnt the 96 trans and transfercase work? Just would lose auto 4 wheel

 

[tayto]

the tailshaft bolt pattern is different from the (one piece) 96 unit vs the 98. so you need to swap a complete 96 4l60e w/ transfer case

 

[Natedawwg]

Would i also use the computer and the transfercase control out of the 96? Ive heard horror stories on these 1 year or 2 year specific. So does the rpo code even matter? The 96 says m30 stamped on the housing. The 98 is the later trans im thinking the previous owner put the wrong trans in it. I cant manual shift it into 1 or 2 at all. Just P R N D 3. 1 and 2 its like its not there as in when the colem shift kinda clicks into place. Cant for 1 or 2 the orange indicator is. Not lit up either

 

[L31MaxExpress]

Would i also use the computer and the transfercase control out of the 96? Ive heard horror stories on these 1 year or 2 year specific. So does the rpo code even matter? The 96 says m30 stamped on the housing. The 98 is the later trans im thinking the previous owner put the wrong trans in it. I cant manual shift it into 1 or 2 at all. Just P R N D 3. 1 and 2 its like its not there as in when the colem shift kinda clicks into place. Cant for 1 or 2 the orange indicator is. Not lit up either

GM had my 99 Tahoe blocked out of 1st gear from the factory. I had to pull the column shift lever bracket off the column and grind on it to get manual low out of it. My aunt had a 98 Yukon that was the same way. My other aunt had a 2000 Escalade that was also that way. My brothers 99 Suburban did not have the added metal on the shift lever bracket nor did my 97 Express. Something with drive by urban noise regulations in effect at the time they were made. The lighter GVW trucks and SUVs with 3.08s and 3.42s could stay in manual 1st gear at the specified speed so thus were too loud. Some of the F-cars with 2.73 gears also had a chunk of plastic made into the shifter to prevent manual 1st gear. I have ground on several of the F-car shifters to get 1st gear as well. I could see a blocked out 1st gear shifter bracket not allowing 2nd gear either if the cable or shifter bracket was worn or broken or the cable was not adjusted correctly.

The 98s I have seen came from the factory with the later "LS" looking 4L60Es with the 2 piece bolt on bellhousing and revised tailshaft bolt pattern. My 99 Tahoe had the same unit. The 98-02 vans also used a different transmission crossmember than 96-97 for the mount that was further to the rear. I know because I need to find one for my 6L90E swap and looked at the year ranges recently that GM used them in on the vans. 96-97 are one style of transmission, 98+ is a different. PCM programming also changed in 98. 95 is also year specific on the 4L60Es, the first of the PWM lockup units but also different than the 96-97s.

 

[tayto]

96-2006 are electrically the same. It should work but for the hassle I would just get the 98 trans rebuilt.

 

[Natedawwg]

Thaks lots. Ill pull the column apart to see if it has the extra metal in there sinxe the 96s already took apart i can compare. Is the shift indicator not lighting up i wpuld suspect that its not adjuated correctly. So does the m30 rpo code just mean 4l60E?. When shifting the colem it seem like its in the right spot for 1st but it wont let it.


I will do some more investigating thanks for the insight.